Merge "Separate scheduler host management"

24 files changed, 1613 insertions, 1266 deletions

diff --git a/nova/api/openstack/compute/contrib/zones.py b/nova/api/openstack/compute/contrib/zones.py
index 28e6f0772..b68f3f4f5 100644
--- a/nova/api/openstack/compute/contrib/zones.py
+++ b/nova/api/openstack/compute/contrib/zones.py
@@ -133,16 +133,12 @@ class Controller(object):
     def info(self, req):
         """Return name and capabilities for this zone."""
         context = req.environ['nova.context']
-        items = nova.scheduler.api.get_zone_capabilities(context)
-
-        zone = dict(name=FLAGS.zone_name)
-        caps = FLAGS.zone_capabilities
-        for cap in caps:
-            key, value = cap.split('=')
-            zone[key] = value
-        for item, (min_value, max_value) in items.iteritems():
-            zone[item] = "%s,%s" % (min_value, max_value)
-        return dict(zone=zone)
+        zone_capabs = nova.scheduler.api.get_zone_capabilities(context)
+        # NOTE(comstud): This should probably return, instead:
+        # {'zone': {'name': FLAGS.zone_name,
+        #           'capabilities': zone_capabs}}
+        zone_capabs['name'] = FLAGS.zone_name
+        return dict(zone=zone_capabs)
 
     @wsgi.serializers(xml=ZoneTemplate)
     def show(self, req, id):
diff --git a/nova/scheduler/api.py b/nova/scheduler/api.py
index e913e5191..b05148651 100644
--- a/nova/scheduler/api.py
+++ b/nova/scheduler/api.py
@@ -87,7 +87,20 @@ def zone_update(context, zone_id, data):
 
 def get_zone_capabilities(context):
     """Returns a dict of key, value capabilities for this zone."""
-    return _call_scheduler('get_zone_capabilities', context=context)
+
+    zone_capabs = {}
+
+    # First grab the capabilities of combined services.
+    service_capabs = _call_scheduler('get_service_capabilities', context)
+    for item, (min_value, max_value) in service_capabs.iteritems():
+        zone_capabs[item] = "%s,%s" % (min_value, max_value)
+
+    # Add the capabilities defined by FLAGS
+    caps = FLAGS.zone_capabilities
+    for cap in caps:
+        key, value = cap.split('=')
+        zone_capabs[key] = value
+    return zone_capabs
 
 
 def select(context, specs=None):
diff --git a/nova/scheduler/chance.py b/nova/scheduler/chance.py
index be66eb3c6..079c1cfc3 100644
--- a/nova/scheduler/chance.py
+++ b/nova/scheduler/chance.py
@@ -67,12 +67,11 @@ class ChanceScheduler(driver.Scheduler):
 
     def schedule_run_instance(self, context, request_spec, *_args, **kwargs):
         """Create and run an instance or instances"""
-        elevated = context.elevated()
         num_instances = request_spec.get('num_instances', 1)
         instances = []
         for num in xrange(num_instances):
             host = self._schedule(context, 'compute', request_spec, **kwargs)
-            instance = self.create_instance_db_entry(elevated, request_spec)
+            instance = self.create_instance_db_entry(context, request_spec)
             driver.cast_to_compute_host(context, host,
                     'run_instance', instance_uuid=instance['uuid'], **kwargs)
             instances.append(driver.encode_instance(instance))
@@ -85,4 +84,4 @@ class ChanceScheduler(driver.Scheduler):
     def schedule_prep_resize(self, context, request_spec, *args, **kwargs):
         """Select a target for resize."""
         host = self._schedule(context, 'compute', request_spec, **kwargs)
-        driver.cast_to_host(context, 'compute', host, 'prep_resize', **kwargs)
+        driver.cast_to_compute_host(context, host, 'prep_resize', **kwargs)
diff --git a/nova/scheduler/distributed_scheduler.py b/nova/scheduler/distributed_scheduler.py
index 754945fe5..4e3c7c277 100644
--- a/nova/scheduler/distributed_scheduler.py
+++ b/nova/scheduler/distributed_scheduler.py
@@ -33,16 +33,13 @@ from nova import flags
 from nova import log as logging
 from nova.scheduler import api
 from nova.scheduler import driver
+from nova.scheduler import host_manager
 from nova.scheduler import least_cost
 from nova.scheduler import scheduler_options
 from nova import utils
 
 
 FLAGS = flags.FLAGS
-flags.DEFINE_list('default_host_filters', ['InstanceTypeFilter'],
-        'Which filters to use for filtering hosts when not specified '
-        'in the request.')
-
 LOG = logging.getLogger('nova.scheduler.distributed_scheduler')
 
 
@@ -108,11 +105,11 @@ class DistributedScheduler(driver.Scheduler):
             weighted_host = weighted_hosts.pop(0)
 
             instance = None
-            if weighted_host.host:
-                instance = self._provision_resource_locally(elevated,
+            if weighted_host.zone:
+                instance = self._ask_child_zone_to_create_instance(elevated,
                                         weighted_host, request_spec, kwargs)
             else:
-                instance = self._ask_child_zone_to_create_instance(elevated,
+                instance = self._provision_resource_locally(elevated,
                                         weighted_host, request_spec, kwargs)
 
             if instance:
@@ -145,8 +142,8 @@ class DistributedScheduler(driver.Scheduler):
         host = hosts.pop(0)
 
         # Forward off to the host
-        driver.cast_to_host(context, 'compute', host.host, 'prep_resize',
-                            **kwargs)
+        driver.cast_to_compute_host(context, host.host_state.host,
+                'prep_resize', **kwargs)
 
     def select(self, context, request_spec, *args, **kwargs):
         """Select returns a list of weights and zone/host information
@@ -167,7 +164,7 @@ class DistributedScheduler(driver.Scheduler):
                                     kwargs):
         """Create the requested resource in this Zone."""
         instance = self.create_instance_db_entry(context, request_spec)
-        driver.cast_to_compute_host(context, weighted_host.host,
+        driver.cast_to_compute_host(context, weighted_host.host_state.host,
                 'run_instance', instance_uuid=instance['uuid'], **kwargs)
         inst = driver.encode_instance(instance, local=True)
         # So if another instance is created, create_instance_db_entry will
@@ -189,7 +186,8 @@ class DistributedScheduler(driver.Scheduler):
             blob = wh_dict.get('blob', None)
             zone = wh_dict.get('zone', None)
             return least_cost.WeightedHost(wh_dict['weight'],
-                        host=host, blob=blob, zone=zone)
+                        host_state=host_manager.HostState(host, 'compute'),
+                        blob=blob, zone=zone)
 
         except M2Crypto.EVP.EVPError:
             raise InvalidBlob()
@@ -265,8 +263,8 @@ class DistributedScheduler(driver.Scheduler):
                         cooked_weight = offset + scale * raw_weight
 
                         weighted_hosts.append(least_cost.WeightedHost(
-                           host=None, weight=cooked_weight,
-                           zone=zone_id, blob=item['blob']))
+                               cooked_weight, zone=zone_id,
+                               blob=item['blob']))
                     except KeyError:
                         LOG.exception(_("Bad child zone scaling values "
                                 "for Zone: %(zone_id)s") % locals())
@@ -280,6 +278,17 @@ class DistributedScheduler(driver.Scheduler):
         """Fetch options dictionary. Broken out for testing."""
         return self.options.get_configuration()
 
+    def populate_filter_properties(self, request_spec, filter_properties):
+        """Stuff things into filter_properties.  Can be overriden in a
+        subclass to add more data.
+        """
+        try:
+            if request_spec['avoid_original_host']:
+                original_host = request_spec['instance_properties']['host']
+                filter_properties['ignore_hosts'].append(original_host)
+        except (KeyError, TypeError):
+            pass
+
     def _schedule(self, elevated, topic, request_spec, *args, **kwargs):
         """Returns a list of hosts that meet the required specs,
         ordered by their fitness.
@@ -288,6 +297,7 @@ class DistributedScheduler(driver.Scheduler):
             msg = _("Scheduler only understands Compute nodes (for now)")
             raise NotImplementedError(msg)
 
+        instance_properties = request_spec['instance_properties']
         instance_type = request_spec.get("instance_type", None)
         if not instance_type:
             msg = _("Scheduler only understands InstanceType-based" \
@@ -299,7 +309,13 @@ class DistributedScheduler(driver.Scheduler):
         ram_requirement_mb = instance_type['memory_mb']
         disk_requirement_gb = instance_type['local_gb']
 
-        options = self._get_configuration_options()
+        config_options = self._get_configuration_options()
+
+        filter_properties = {'config_options': config_options,
+                             'instance_type': instance_type,
+                             'ignore_hosts': []}
+
+        self.populate_filter_properties(request_spec, filter_properties)
 
         # Find our local list of acceptable hosts by repeatedly
         # filtering and weighing our options. Each time we choose a
@@ -307,33 +323,37 @@ class DistributedScheduler(driver.Scheduler):
         # selections can adjust accordingly.
 
         # unfiltered_hosts_dict is {host : ZoneManager.HostInfo()}
-        unfiltered_hosts_dict = self.zone_manager.get_all_host_data(elevated)
-        unfiltered_hosts = unfiltered_hosts_dict.items()
+        unfiltered_hosts_dict = self.host_manager.get_all_host_states(
+                elevated, topic)
+        hosts = unfiltered_hosts_dict.itervalues()
 
         num_instances = request_spec.get('num_instances', 1)
         selected_hosts = []
         for num in xrange(num_instances):
             # Filter local hosts based on requirements ...
-            filtered_hosts = self._filter_hosts(topic, request_spec,
-                    unfiltered_hosts, options)
-
-            if not filtered_hosts:
+            hosts = self.host_manager.filter_hosts(hosts,
+                    filter_properties)
+            if not hosts:
                 # Can't get any more locally.
                 break
 
-            LOG.debug(_("Filtered %(filtered_hosts)s") % locals())
+            LOG.debug(_("Filtered %(hosts)s") % locals())
 
             # weighted_host = WeightedHost() ... the best
             # host for the job.
+            # TODO(comstud): filter_properties will also be used for
+            # weighing and I plan fold weighing into the host manager
+            # in a future patch.  I'll address the naming of this
+            # variable at that time.
             weighted_host = least_cost.weighted_sum(cost_functions,
-                                                filtered_hosts, options)
+                    hosts, filter_properties)
             LOG.debug(_("Weighted %(weighted_host)s") % locals())
             selected_hosts.append(weighted_host)
 
             # Now consume the resources so the filter/weights
             # will change for the next instance.
-            weighted_host.hostinfo.consume_resources(disk_requirement_gb,
-                                        ram_requirement_mb)
+            weighted_host.host_state.consume_from_instance(
+                    instance_properties)
 
         # Next, tack on the host weights from the child zones
         if not request_spec.get('local_zone', False):
@@ -346,72 +366,6 @@ class DistributedScheduler(driver.Scheduler):
         selected_hosts.sort(key=operator.attrgetter('weight'))
         return selected_hosts[:num_instances]
 
-    def _get_filter_classes(self):
-        # Imported here to avoid circular imports
-        from nova.scheduler import filters
-
-        def get_itm(nm):
-            return getattr(filters, nm)
-
-        return [get_itm(itm) for itm in dir(filters)
-                if isinstance(get_itm(itm), type)
-                and issubclass(get_itm(itm), filters.AbstractHostFilter)
-                and get_itm(itm) is not filters.AbstractHostFilter]
-
-    def _choose_host_filters(self, filters=None):
-        """Since the caller may specify which filters to use we need
-        to have an authoritative list of what is permissible. This
-        function checks the filter names against a predefined set
-        of acceptable filters.
-        """
-        if not filters:
-            filters = FLAGS.default_host_filters
-        if not isinstance(filters, (list, tuple)):
-            filters = [filters]
-        good_filters = []
-        bad_filters = []
-        filter_classes = self._get_filter_classes()
-        for filter_name in filters:
-            found_class = False
-            for cls in filter_classes:
-                if cls.__name__ == filter_name:
-                    good_filters.append(cls())
-                    found_class = True
-                    break
-            if not found_class:
-                bad_filters.append(filter_name)
-        if bad_filters:
-            msg = ", ".join(bad_filters)
-            raise exception.SchedulerHostFilterNotFound(filter_name=msg)
-        return good_filters
-
-    def _filter_hosts(self, topic, request_spec, hosts, options):
-        """Filter the full host list. hosts = [(host, HostInfo()), ...].
-        This method returns a subset of hosts, in the same format."""
-        selected_filters = self._choose_host_filters()
-
-        # Filter out original host
-        try:
-            if request_spec['avoid_original_host']:
-                original_host = request_spec['instance_properties']['host']
-                hosts = [(h, hi) for h, hi in hosts if h != original_host]
-        except (KeyError, TypeError):
-            pass
-
-        # TODO(sandy): We're only using InstanceType-based specs
-        # currently. Later we'll need to snoop for more detailed
-        # host filter requests.
-        instance_type = request_spec.get("instance_type", None)
-        if instance_type is None:
-            # No way to select; return the specified hosts.
-            return hosts
-
-        for selected_filter in selected_filters:
-            query = selected_filter.instance_type_to_filter(instance_type)
-            hosts = selected_filter.filter_hosts(hosts, query, options)
-
-        return hosts
-
     def get_cost_functions(self, topic=None):
         """Returns a list of tuples containing weights and cost functions to
         use for weighing hosts
diff --git a/nova/scheduler/driver.py b/nova/scheduler/driver.py
index b3b598de9..46d7046da 100644
--- a/nova/scheduler/driver.py
+++ b/nova/scheduler/driver.py
@@ -21,22 +21,30 @@
 Scheduler base class that all Schedulers should inherit from
 """
 
+from nova.api.ec2 import ec2utils
+from nova.compute import api as compute_api
+from nova.compute import power_state
+from nova.compute import vm_states
 from nova import db
 from nova import exception
 from nova import flags
 from nova import log as logging
 from nova import rpc
+from nova.scheduler import host_manager
+from nova.scheduler import zone_manager
 from nova import utils
-from nova.compute import api as compute_api
-from nova.compute import power_state
-from nova.compute import vm_states
-from nova.api.ec2 import ec2utils
 
 
 FLAGS = flags.FLAGS
 LOG = logging.getLogger('nova.scheduler.driver')
 flags.DEFINE_integer('service_down_time', 60,
                      'maximum time since last check-in for up service')
+flags.DEFINE_string('scheduler_host_manager',
+        'nova.scheduler.host_manager.HostManager',
+        'The scheduler host manager class to use')
+flags.DEFINE_string('scheduler_zone_manager',
+        'nova.scheduler.zone_manager.ZoneManager',
+        'The scheduler zone manager class to use')
 flags.DECLARE('instances_path', 'nova.compute.manager')
 
 
@@ -113,20 +121,43 @@ def encode_instance(instance, local=True):
     if local:
         return dict(id=instance['id'], _is_precooked=False)
     else:
-        instance['_is_precooked'] = True
-        return instance
+        inst = dict(instance)
+        inst['_is_precooked'] = True
+        return inst
 
 
 class Scheduler(object):
     """The base class that all Scheduler classes should inherit from."""
 
     def __init__(self):
-        self.zone_manager = None
+        self.zone_manager = utils.import_object(
+                FLAGS.scheduler_zone_manager)
+        self.host_manager = utils.import_object(
+                FLAGS.scheduler_host_manager)
         self.compute_api = compute_api.API()
 
-    def set_zone_manager(self, zone_manager):
-        """Called by the Scheduler Service to supply a ZoneManager."""
-        self.zone_manager = zone_manager
+    def get_host_list(self):
+        """Get a list of hosts from the HostManager."""
+        return self.host_manager.get_host_list()
+
+    def get_zone_list(self):
+        """Get a list of zones from the ZoneManager."""
+        return self.zone_manager.get_zone_list()
+
+    def get_service_capabilities(self):
+        """Get the normalized set of capabilities for the services
+        in this zone.
+        """
+        return self.host_manager.get_service_capabilities()
+
+    def update_service_capabilities(self, service_name, host, capabilities):
+        """Process a capability update from a service node."""
+        self.host_manager.update_service_capabilities(service_name,
+                host, capabilities)
+
+    def poll_child_zones(self, context):
+        """Poll child zones periodically to get status."""
+        return self.zone_manager.update(context)
 
     @staticmethod
     def service_is_up(service):
@@ -140,7 +171,7 @@ class Scheduler(object):
         """Return the list of hosts that have a running service for topic."""
 
         services = db.service_get_all_by_topic(context, topic)
-        return [service.host
+        return [service['host']
                 for service in services
                 if self.service_is_up(service)]
 
@@ -168,6 +199,10 @@ class Scheduler(object):
         """Must override at least this method for scheduler to work."""
         raise NotImplementedError(_("Must implement a fallback schedule"))
 
+    def select(self, context, topic, method, *_args, **_kwargs):
+        """Must override this for zones to work."""
+        raise NotImplementedError(_("Must implement 'select' method"))
+
     def schedule_live_migration(self, context, instance_id, dest,
                                 block_migration=False,
                                 disk_over_commit=False):
@@ -232,7 +267,7 @@ class Scheduler(object):
         # to the instance.
         if len(instance_ref['volumes']) != 0:
             services = db.service_get_all_by_topic(context, 'volume')
-            if len(services) < 1 or  not self.service_is_up(services[0]):
+            if len(services) < 1 or not self.service_is_up(services[0]):
                 raise exception.VolumeServiceUnavailable()
 
         # Checking src host exists and compute node
@@ -302,6 +337,7 @@ class Scheduler(object):
                 reason = _("Block migration can not be used "
                            "with shared storage.")
                 raise exception.InvalidSharedStorage(reason=reason, path=dest)
+        # FIXME(comstud): See LP891756.
         except exception.FileNotFound:
             if not block_migration:
                 src = instance_ref['host']
diff --git a/nova/scheduler/filters/__init__.py b/nova/scheduler/filters/__init__.py
index b86fb795f..f9bf6641b 100644
--- a/nova/scheduler/filters/__init__.py
+++ b/nova/scheduler/filters/__init__.py
@@ -32,5 +32,5 @@ InstanceType filter.
 
 from abstract_filter import AbstractHostFilter
 from all_hosts_filter import AllHostsFilter
-from instance_type_filter import InstanceTypeFilter
+from compute_filter import ComputeFilter
 from json_filter import JsonFilter
diff --git a/nova/scheduler/filters/abstract_filter.py b/nova/scheduler/filters/abstract_filter.py
index 2ce235094..235eaa74b 100644
--- a/nova/scheduler/filters/abstract_filter.py
+++ b/nova/scheduler/filters/abstract_filter.py
@@ -16,13 +16,9 @@
 
 class AbstractHostFilter(object):
     """Base class for host filters."""
-    def instance_type_to_filter(self, instance_type):
-        """Convert instance_type into a filter for most common use-case."""
-        raise NotImplementedError()
 
-    def filter_hosts(self, host_list, query, options):
-        """Return a list of hosts that fulfill the filter."""
-        raise NotImplementedError()
+    def host_passes(self, host_state, filter_properties):
+        return True
 
     def _full_name(self):
         """module.classname of the filter."""
diff --git a/nova/scheduler/filters/all_hosts_filter.py b/nova/scheduler/filters/all_hosts_filter.py
index 9e3bc5a39..1099e425d 100644
--- a/nova/scheduler/filters/all_hosts_filter.py
+++ b/nova/scheduler/filters/all_hosts_filter.py
@@ -1,4 +1,4 @@
-# Copyright (c) 2011 Openstack, LLC.
+# Copyright (c) 2011-2012 Openstack, LLC.
 # All Rights Reserved.
 #
 #    Licensed under the Apache License, Version 2.0 (the "License"); you may
@@ -18,13 +18,7 @@ import abstract_filter
 
 
 class AllHostsFilter(abstract_filter.AbstractHostFilter):
-    """NOP host filter. Returns all hosts in ZoneManager."""
-    def instance_type_to_filter(self, instance_type):
-        """Return anything to prevent base-class from raising
-        exception.
-        """
-        return instance_type
+    """NOP host filter. Returns all hosts."""
 
-    def filter_hosts(self, host_list, query, options):
-        """Return the entire list of supplied hosts."""
-        return list(host_list)
+    def host_passes(self, host_state, filter_properties):
+        return True
diff --git a/nova/scheduler/filters/instance_type_filter.py b/nova/scheduler/filters/compute_filter.py
index 1b490dd5a..a31fffc6a 100644
--- a/nova/scheduler/filters/instance_type_filter.py
+++ b/nova/scheduler/filters/compute_filter.py
@@ -13,19 +13,15 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import logging
-
+from nova import log as logging
 from nova.scheduler.filters import abstract_filter
 
 
-LOG = logging.getLogger('nova.scheduler.filter.instance_type_filter')
+LOG = logging.getLogger('nova.scheduler.filter.compute_filter')
 
 
-class InstanceTypeFilter(abstract_filter.AbstractHostFilter):
+class ComputeFilter(abstract_filter.AbstractHostFilter):
     """HostFilter hard-coded to work with InstanceType records."""
-    def instance_type_to_filter(self, instance_type):
-        """Use instance_type to filter hosts."""
-        return instance_type
 
     def _satisfies_extra_specs(self, capabilities, instance_type):
         """Check that the capabilities provided by the compute service
@@ -36,35 +32,28 @@ class InstanceTypeFilter(abstract_filter.AbstractHostFilter):
         # NOTE(lorinh): For now, we are just checking exact matching on the
         # values. Later on, we want to handle numerical
         # values so we can represent things like number of GPU cards
-        try:
-            for key, value in instance_type['extra_specs'].iteritems():
-                if capabilities[key] != value:
-                    return False
-        except KeyError, e:
-            return False
+        for key, value in instance_type['extra_specs'].iteritems():
+            if capabilities.get(key, None) != value:
+                return False
         return True
 
-    def _basic_ram_filter(self, host_name, host_info, instance_type):
+    def _basic_ram_filter(self, host_state, instance_type):
         """Only return hosts with sufficient available RAM."""
         requested_ram = instance_type['memory_mb']
-        free_ram_mb = host_info.free_ram_mb
+        free_ram_mb = host_state.free_ram_mb
         return free_ram_mb >= requested_ram
 
-    def filter_hosts(self, host_list, query, options):
+    def host_passes(self, host_state, filter_properties):
         """Return a list of hosts that can create instance_type."""
-        instance_type = query
-        selected_hosts = []
-        for hostname, host_info in host_list:
-            if not self._basic_ram_filter(hostname, host_info,
-                                          instance_type):
-                continue
-            capabilities = host_info.compute
-            if capabilities:
-                if not capabilities.get("enabled", True):
-                    continue
-                if not self._satisfies_extra_specs(capabilities,
-                                                   instance_type):
-                    continue
+        instance_type = filter_properties.get('instance_type')
+        if host_state.topic != 'compute' or not instance_type:
+            return True
+        capabilities = host_state.capabilities or {}
 
-            selected_hosts.append((hostname, host_info))
-        return selected_hosts
+        if not self._basic_ram_filter(host_state, instance_type):
+            return False
+        if not capabilities.get("enabled", True):
+            return False
+        if not self._satisfies_extra_specs(capabilities, instance_type):
+            return False
+        return True
diff --git a/nova/scheduler/filters/json_filter.py b/nova/scheduler/filters/json_filter.py
index a64a5f5ed..53752df8c 100644
--- a/nova/scheduler/filters/json_filter.py
+++ b/nova/scheduler/filters/json_filter.py
@@ -86,18 +86,11 @@ class JsonFilter(abstract_filter.AbstractHostFilter):
         'and': _and,
     }
 
-    def instance_type_to_filter(self, instance_type):
-        """Convert instance_type into JSON filter object."""
-        required_ram = instance_type['memory_mb']
-        required_disk = instance_type['local_gb']
-        query = ['and',
-                ['>=', '$compute.host_memory_free', required_ram],
-                ['>=', '$compute.disk_available', required_disk]]
-        return json.dumps(query)
-
-    def _parse_string(self, string, host, hostinfo):
+    def _parse_string(self, string, host_state):
         """Strings prefixed with $ are capability lookups in the
-        form '$service.capability[.subcap*]'.
+        form '$variable' where 'variable' is an attribute in the
+        HostState class.  If $variable is a dictionary, you may
+        use: $variable.dictkey
         """
         if not string:
             return None
@@ -105,18 +98,16 @@ class JsonFilter(abstract_filter.AbstractHostFilter):
             return string
 
         path = string[1:].split(".")
-        services = dict(compute=hostinfo.compute, network=hostinfo.network,
-                        volume=hostinfo.volume)
-        service = services.get(path[0], None)
-        if not service:
+        obj = getattr(host_state, path[0], None)
+        if obj is None:
             return None
         for item in path[1:]:
-            service = service.get(item, None)
-            if not service:
+            obj = obj.get(item, None)
+            if obj is None:
                 return None
-        return service
+        return obj
 
-    def _process_filter(self, query, host, hostinfo):
+    def _process_filter(self, query, host_state):
         """Recursively parse the query structure."""
         if not query:
             return True
@@ -125,30 +116,31 @@ class JsonFilter(abstract_filter.AbstractHostFilter):
         cooked_args = []
         for arg in query[1:]:
             if isinstance(arg, list):
-                arg = self._process_filter(arg, host, hostinfo)
+                arg = self._process_filter(arg, host_state)
             elif isinstance(arg, basestring):
-                arg = self._parse_string(arg, host, hostinfo)
+                arg = self._parse_string(arg, host_state)
             if arg is not None:
                 cooked_args.append(arg)
         result = method(self, cooked_args)
         return result
 
-    def filter_hosts(self, host_list, query, options):
+    def host_passes(self, host_state, filter_properties):
         """Return a list of hosts that can fulfill the requirements
         specified in the query.
         """
-        expanded = json.loads(query)
-        filtered_hosts = []
-        for host, hostinfo in host_list:
-            if not hostinfo:
-                continue
-            if hostinfo.compute and not hostinfo.compute.get("enabled", True):
-                # Host is disabled
-                continue
-            result = self._process_filter(expanded, host, hostinfo)
-            if isinstance(result, list):
-                # If any succeeded, include the host
-                result = any(result)
-            if result:
-                filtered_hosts.append((host, hostinfo))
-        return filtered_hosts
+        capabilities = host_state.capabilities or {}
+        if not capabilities.get("enabled", True):
+            return False
+
+        query = filter_properties.get('query', None)
+        if not query:
+            return True
+
+        result = self._process_filter(json.loads(query), host_state)
+        if isinstance(result, list):
+            # If any succeeded, include the host
+            result = any(result)
+        if result:
+            # Filter it out.
+            return True
+        return False
diff --git a/nova/scheduler/host_manager.py b/nova/scheduler/host_manager.py
new file mode 100644
index 000000000..04eff39b5
--- /dev/null
+++ b/nova/scheduler/host_manager.py
@@ -0,0 +1,310 @@
+# Copyright (c) 2011 Openstack, LLC.
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+"""
+Manage hosts in the current zone.
+"""
+
+import datetime
+import types
+import UserDict
+
+from nova import db
+from nova import exception
+from nova import flags
+from nova import log as logging
+from nova import utils
+
+FLAGS = flags.FLAGS
+flags.DEFINE_integer('reserved_host_disk_mb', 0,
+        'Amount of disk in MB to reserve for host/dom0')
+flags.DEFINE_integer('reserved_host_memory_mb', 512,
+        'Amount of memory in MB to reserve for host/dom0')
+flags.DEFINE_list('default_host_filters', ['ComputeFilter'],
+        'Which filters to use for filtering hosts when not specified '
+        'in the request.')
+
+LOG = logging.getLogger('nova.scheduler.host_manager')
+
+
+class ReadOnlyDict(UserDict.IterableUserDict):
+    """A read-only dict."""
+    def __init__(self, source=None):
+        self.data = {}
+        self.update(source)
+
+    def __setitem__(self, key, item):
+        raise TypeError
+
+    def __delitem__(self, key):
+        raise TypeError
+
+    def clear(self):
+        raise TypeError
+
+    def pop(self, key, *args):
+        raise TypeError
+
+    def popitem(self):
+        raise TypeError
+
+    def update(self, source=None):
+        if source is None:
+            return
+        elif isinstance(source, UserDict.UserDict):
+            self.data = source.data
+        elif isinstance(source, type({})):
+            self.data = source
+        else:
+            raise TypeError
+
+
+class HostState(object):
+    """Mutable and immutable information tracked for a host.
+    This is an attempt to remove the ad-hoc data structures
+    previously used and lock down access.
+    """
+
+    def __init__(self, host, topic, capabilities=None):
+        self.host = host
+        self.topic = topic
+
+        # Read-only capability dicts
+
+        if capabilities is None:
+            capabilities = {}
+        self.capabilities = ReadOnlyDict(capabilities.get(topic, None))
+        # Mutable available resources.
+        # These will change as resources are virtually "consumed".
+        self.free_ram_mb = 0
+        self.free_disk_mb = 0
+
+    def update_from_compute_node(self, compute):
+        """Update information about a host from its compute_node info."""
+        all_disk_mb = compute['local_gb'] * 1024
+        all_ram_mb = compute['memory_mb']
+        if FLAGS.reserved_host_disk_mb > 0:
+            all_disk_mb -= FLAGS.reserved_host_disk_mb
+        if FLAGS.reserved_host_memory_mb > 0:
+            all_ram_mb -= FLAGS.reserved_host_memory_mb
+        self.free_ram_mb = all_ram_mb
+        self.free_disk_mb = all_disk_mb
+
+    def consume_from_instance(self, instance):
+        """Update information about a host from instance info."""
+        disk_mb = instance['local_gb'] * 1024
+        ram_mb = instance['memory_mb']
+        self.free_ram_mb -= ram_mb
+        self.free_disk_mb -= disk_mb
+
+    def passes_filters(self, filter_fns, filter_properties):
+        """Return whether or not this host passes filters."""
+
+        if self.host in filter_properties.get('ignore_hosts', []):
+            return False
+        for filter_fn in filter_fns:
+            if not filter_fn(self, filter_properties):
+                return False
+        return True
+
+    def __repr__(self):
+        return "host '%s': free_ram_mb:%s free_disk_mb:%s" % \
+                    (self.host, self.free_ram_mb, self.free_disk_mb)
+
+
+class HostManager(object):
+    """Base HostManager class."""
+
+    # Can be overriden in a subclass
+    host_state_cls = HostState
+
+    def __init__(self):
+        self.service_states = {}  # { <host> : { <service> : { cap k : v }}}
+        self.filter_classes = self._get_filter_classes()
+
+    def _get_filter_classes(self):
+        """Get the list of possible filter classes"""
+        # Imported here to avoid circular imports
+        from nova.scheduler import filters
+
+        def get_itm(nm):
+            return getattr(filters, nm)
+
+        return [get_itm(itm) for itm in dir(filters)
+                if (type(get_itm(itm)) is types.TypeType)
+                and issubclass(get_itm(itm), filters.AbstractHostFilter)
+                and get_itm(itm) is not filters.AbstractHostFilter]
+
+    def _choose_host_filters(self, filters):
+        """Since the caller may specify which filters to use we need
+        to have an authoritative list of what is permissible. This
+        function checks the filter names against a predefined set
+        of acceptable filters.
+        """
+        if filters is None:
+            filters = FLAGS.default_host_filters
+        if not isinstance(filters, (list, tuple)):
+            filters = [filters]
+        good_filters = []
+        bad_filters = []
+        for filter_name in filters:
+            found_class = False
+            for cls in self.filter_classes:
+                if cls.__name__ == filter_name:
+                    found_class = True
+                    filter_instance = cls()
+                    # Get the filter function
+                    filter_func = getattr(filter_instance,
+                            'host_passes', None)
+                    if filter_func:
+                        good_filters.append(filter_func)
+                    break
+            if not found_class:
+                bad_filters.append(filter_name)
+        if bad_filters:
+            msg = ", ".join(bad_filters)
+            raise exception.SchedulerHostFilterNotFound(filter_name=msg)
+        return good_filters
+
+    def filter_hosts(self, hosts, filter_properties, filters=None):
+        """Filter hosts and return only ones passing all filters"""
+        filtered_hosts = []
+        filter_fns = self._choose_host_filters(filters)
+        for host in hosts:
+            if host.passes_filters(filter_fns, filter_properties):
+                filtered_hosts.append(host)
+        return filtered_hosts
+
+    def get_host_list(self):
+        """Returns a list of dicts for each host that the Zone Manager
+        knows about. Each dict contains the host_name and the service
+        for that host.
+        """
+        all_hosts = self.service_states.keys()
+        ret = []
+        for host in self.service_states:
+            for svc in self.service_states[host]:
+                ret.append({"service": svc, "host_name": host})
+        return ret
+
+    def get_service_capabilities(self):
+        """Roll up all the individual host info to generic 'service'
+           capabilities. Each capability is aggregated into
+           <cap>_min and <cap>_max values."""
+        hosts_dict = self.service_states
+
+        # TODO(sandy) - be smarter about fabricating this structure.
+        # But it's likely to change once we understand what the Best-Match
+        # code will need better.
+        combined = {}  # { <service>_<cap> : (min, max), ... }
+        stale_host_services = {}  # { host1 : [svc1, svc2], host2 :[svc1]}
+        for host, host_dict in hosts_dict.iteritems():
+            for service_name, service_dict in host_dict.iteritems():
+                if not service_dict.get("enabled", True):
+                    # Service is disabled; do no include it
+                    continue
+
+                # Check if the service capabilities became stale
+                if self.host_service_caps_stale(host, service_name):
+                    if host not in stale_host_services:
+                        stale_host_services[host] = []  # Adding host key once
+                    stale_host_services[host].append(service_name)
+                    continue
+                for cap, value in service_dict.iteritems():
+                    if cap == "timestamp":  # Timestamp is not needed
+                        continue
+                    key = "%s_%s" % (service_name, cap)
+                    min_value, max_value = combined.get(key, (value, value))
+                    min_value = min(min_value, value)
+                    max_value = max(max_value, value)
+                    combined[key] = (min_value, max_value)
+
+        # Delete the expired host services
+        self.delete_expired_host_services(stale_host_services)
+        return combined
+
+    def update_service_capabilities(self, service_name, host, capabilities):
+        """Update the per-service capabilities based on this notification."""
+        logging.debug(_("Received %(service_name)s service update from "
+                "%(host)s.") % locals())
+        service_caps = self.service_states.get(host, {})
+        # Copy the capabilities, so we don't modify the original dict
+        capab_copy = dict(capabilities)
+        capab_copy["timestamp"] = utils.utcnow()  # Reported time
+        service_caps[service_name] = capab_copy
+        self.service_states[host] = service_caps
+
+    def host_service_caps_stale(self, host, service):
+        """Check if host service capabilites are not recent enough."""
+        allowed_time_diff = FLAGS.periodic_interval * 3
+        caps = self.service_states[host][service]
+        if (utils.utcnow() - caps["timestamp"]) <= \
+            datetime.timedelta(seconds=allowed_time_diff):
+            return False
+        return True
+
+    def delete_expired_host_services(self, host_services_dict):
+        """Delete all the inactive host services information."""
+        for host, services in host_services_dict.iteritems():
+            service_caps = self.service_states[host]
+            for service in services:
+                del service_caps[service]
+                if len(service_caps) == 0:  # Delete host if no services
+                    del self.service_states[host]
+
+    def get_all_host_states(self, context, topic):
+        """Returns a dict of all the hosts the HostManager
+        knows about. Also, each of the consumable resources in HostState
+        are pre-populated and adjusted based on data in the db.
+
+        For example:
+        {'192.168.1.100': HostState(), ...}
+
+        Note: this can be very slow with a lot of instances.
+        InstanceType table isn't required since a copy is stored
+        with the instance (in case the InstanceType changed since the
+        instance was created)."""
+
+        if topic != 'compute':
+            raise NotImplementedError(_(
+                "host_manager only implemented for 'compute'"))
+
+        host_state_map = {}
+
+        # Make a compute node dict with the bare essential metrics.
+        compute_nodes = db.compute_node_get_all(context)
+        for compute in compute_nodes:
+            service = compute['service']
+            if not service:
+                logging.warn(_("No service for compute ID %s") % compute['id'])
+                continue
+            host = service['host']
+            capabilities = self.service_states.get(host, None)
+            host_state = self.host_state_cls(host, topic,
+                    capabilities=capabilities)
+            host_state.update_from_compute_node(compute)
+            host_state_map[host] = host_state
+
+        # "Consume" resources from the host the instance resides on.
+        instances = db.instance_get_all(context)
+        for instance in instances:
+            host = instance['host']
+            if not host:
+                continue
+            host_state = host_state_map.get(host, None)
+            if not host_state:
+                continue
+            host_state.consume_from_instance(instance)
+        return host_state_map
diff --git a/nova/scheduler/least_cost.py b/nova/scheduler/least_cost.py
index bb9c78e80..c14e93747 100644
--- a/nova/scheduler/least_cost.py
+++ b/nova/scheduler/least_cost.py
@@ -47,38 +47,37 @@ class WeightedHost(object):
     This is an attempt to remove some of the ad-hoc dict structures
     previously used."""
 
-    def __init__(self, weight, host=None, blob=None, zone=None, hostinfo=None):
+    def __init__(self, weight, host_state=None, blob=None, zone=None):
         self.weight = weight
         self.blob = blob
-        self.host = host
         self.zone = zone
 
         # Local members. These are not returned outside of the Zone.
-        self.hostinfo = hostinfo
+        self.host_state = host_state
 
     def to_dict(self):
         x = dict(weight=self.weight)
         if self.blob:
             x['blob'] = self.blob
-        if self.host:
-            x['host'] = self.host
+        if self.host_state:
+            x['host'] = self.host_state.host
         if self.zone:
             x['zone'] = self.zone
         return x
 
 
-def noop_cost_fn(host_info, options=None):
+def noop_cost_fn(host_state, weighing_properties):
     """Return a pre-weight cost of 1 for each host"""
     return 1
 
 
-def compute_fill_first_cost_fn(host_info, options=None):
+def compute_fill_first_cost_fn(host_state, weighing_properties):
     """More free ram = higher weight. So servers will less free
     ram will be preferred."""
-    return host_info.free_ram_mb
+    return host_state.free_ram_mb
 
 
-def weighted_sum(weighted_fns, host_list, options):
+def weighted_sum(weighted_fns, host_states, weighing_properties):
     """Use the weighted-sum method to compute a score for an array of objects.
     Normalize the results of the objective-functions so that the weights are
     meaningful regardless of objective-function's range.
@@ -86,7 +85,8 @@ def weighted_sum(weighted_fns, host_list, options):
     host_list - [(host, HostInfo()), ...]
     weighted_fns - list of weights and functions like:
         [(weight, objective-functions), ...]
-    options is an arbitrary dict of values.
+    weighing_properties is an arbitrary dict of values that can influence
+        weights.
 
     Returns a single WeightedHost object which represents the best
     candidate.
@@ -96,8 +96,8 @@ def weighted_sum(weighted_fns, host_list, options):
     # One row per host. One column per function.
     scores = []
     for weight, fn in weighted_fns:
-        scores.append([fn(host_info, options) for hostname, host_info
-                                                                in host_list])
+        scores.append([fn(host_state, weighing_properties)
+                for host_state in host_states])
 
     # Adjust the weights in the grid by the functions weight adjustment
     # and sum them up to get a final list of weights.
@@ -106,16 +106,16 @@ def weighted_sum(weighted_fns, host_list, options):
         adjusted_scores.append([weight * score for score in row])
 
     # Now, sum down the columns to get the final score. Column per host.
-    final_scores = [0.0] * len(host_list)
+    final_scores = [0.0] * len(host_states)
     for row in adjusted_scores:
         for idx, col in enumerate(row):
             final_scores[idx] += col
 
-    # Super-impose the hostinfo into the scores so
+    # Super-impose the host_state into the scores so
     # we don't lose it when we sort.
-    final_scores = [(final_scores[idx], host_tuple)
-                    for idx, host_tuple in enumerate(host_list)]
+    final_scores = [(final_scores[idx], host_state)
+            for idx, host_state in enumerate(host_states)]
 
     final_scores = sorted(final_scores)
-    weight, (host, hostinfo) = final_scores[0]  # Lowest score is the winner!
-    return WeightedHost(weight, host=host, hostinfo=hostinfo)
+    weight, host_state = final_scores[0]  # Lowest score is the winner!
+    return WeightedHost(weight, host_state=host_state)
diff --git a/nova/scheduler/manager.py b/nova/scheduler/manager.py
index c74988cda..33e77cd05 100644
--- a/nova/scheduler/manager.py
+++ b/nova/scheduler/manager.py
@@ -30,7 +30,6 @@ from nova import flags
 from nova import log as logging
 from nova import manager
 from nova import rpc
-from nova.scheduler import zone_manager
 from nova import utils
 
 LOG = logging.getLogger('nova.scheduler.manager')
@@ -44,11 +43,9 @@ class SchedulerManager(manager.Manager):
     """Chooses a host to run instances on."""
 
     def __init__(self, scheduler_driver=None, *args, **kwargs):
-        self.zone_manager = zone_manager.ZoneManager()
         if not scheduler_driver:
             scheduler_driver = FLAGS.scheduler_driver
         self.driver = utils.import_object(scheduler_driver)
-        self.driver.set_zone_manager(self.zone_manager)
         super(SchedulerManager, self).__init__(*args, **kwargs)
 
     def __getattr__(self, key):
@@ -58,29 +55,29 @@ class SchedulerManager(manager.Manager):
     @manager.periodic_task
     def _poll_child_zones(self, context):
         """Poll child zones periodically to get status."""
-        self.zone_manager.ping(context)
+        self.driver.poll_child_zones(context)
 
-    def get_host_list(self, context=None):
-        """Get a list of hosts from the ZoneManager."""
-        return self.zone_manager.get_host_list()
+    def get_host_list(self, context):
+        """Get a list of hosts from the HostManager."""
+        return self.driver.get_host_list()
 
-    def get_zone_list(self, context=None):
+    def get_zone_list(self, context):
         """Get a list of zones from the ZoneManager."""
-        return self.zone_manager.get_zone_list()
+        return self.driver.get_zone_list()
 
-    def get_zone_capabilities(self, context=None):
+    def get_service_capabilities(self, context):
         """Get the normalized set of capabilities for this zone."""
-        return self.zone_manager.get_zone_capabilities(context)
+        return self.driver.get_service_capabilities()
 
-    def update_service_capabilities(self, context=None, service_name=None,
-                                                host=None, capabilities=None):
+    def update_service_capabilities(self, context, service_name=None,
+            host=None, capabilities=None, **kwargs):
         """Process a capability update from a service node."""
-        if not capabilities:
+        if capabilities is None:
             capabilities = {}
-        self.zone_manager.update_service_capabilities(service_name,
-                            host, capabilities)
+        self.driver.update_service_capabilities(service_name, host,
+                capabilities)
 
-    def select(self, context=None, *args, **kwargs):
+    def select(self, context, *args, **kwargs):
         """Select a list of hosts best matching the provided specs."""
         return self.driver.select(context, *args, **kwargs)
 
diff --git a/nova/scheduler/simple.py b/nova/scheduler/simple.py
index 23a58e5bc..fb800756d 100644
--- a/nova/scheduler/simple.py
+++ b/nova/scheduler/simple.py
@@ -141,20 +141,3 @@ class SimpleScheduler(chance.ChanceScheduler):
                 return None
         msg = _("Is the appropriate service running?")
         raise exception.NoValidHost(reason=msg)
-
-    def schedule_set_network_host(self, context, *_args, **_kwargs):
-        """Picks a host that is up and has the fewest networks."""
-        elevated = context.elevated()
-
-        results = db.service_get_all_network_sorted(elevated)
-        for result in results:
-            (service, instance_count) = result
-            if instance_count >= FLAGS.max_networks:
-                msg = _("Not enough allocatable networks remaining")
-                raise exception.NoValidHost(reason=msg)
-            if self.service_is_up(service):
-                driver.cast_to_network_host(context, service['host'],
-                        'set_network_host', **_kwargs)
-                return None
-        msg = _("Is the appropriate service running?")
-        raise exception.NoValidHost(reason=msg)
diff --git a/nova/scheduler/vsa.py b/nova/scheduler/vsa.py
index e4433694b..dd17b19c6 100644
--- a/nova/scheduler/vsa.py
+++ b/nova/scheduler/vsa.py
@@ -97,7 +97,7 @@ class VsaScheduler(simple.SimpleScheduler):
         return True
 
     def _get_service_states(self):
-        return self.zone_manager.service_states
+        return self.host_manager.service_states
 
     def _filter_hosts(self, topic, request_spec, host_list=None):
 
diff --git a/nova/scheduler/zone_manager.py b/nova/scheduler/zone_manager.py
index 3835b6233..0e86a89c0 100644
--- a/nova/scheduler/zone_manager.py
+++ b/nova/scheduler/zone_manager.py
@@ -14,12 +14,11 @@
 #    under the License.
 
 """
-ZoneManager oversees all communications with child Zones.
+Manage communication with child zones and keep state for them.
 """
 
 import datetime
 import traceback
-import UserDict
 
 from eventlet import greenpool
 from novaclient import v1_1 as novaclient
@@ -34,149 +33,83 @@ flags.DEFINE_integer('zone_db_check_interval', 60,
         'Seconds between getting fresh zone info from db.')
 flags.DEFINE_integer('zone_failures_to_offline', 3,
         'Number of consecutive errors before marking zone offline')
-flags.DEFINE_integer('reserved_host_disk_mb', 0,
-        'Amount of disk in MB to reserve for host/dom0')
-flags.DEFINE_integer('reserved_host_memory_mb', 512,
-        'Amount of memory in MB to reserve for host/dom0')
+
+LOG = logging.getLogger('nova.scheduler.zone_manager')
 
 
 class ZoneState(object):
-    """Holds the state of all connected child zones."""
+    """Holds state for a particular zone."""
     def __init__(self):
         self.is_active = True
-        self.name = None
-        self.capabilities = None
+        self.capabilities = {}
         self.attempt = 0
         self.last_seen = datetime.datetime.min
         self.last_exception = None
         self.last_exception_time = None
+        self.zone_info = {}
 
-    def update_credentials(self, zone):
+    def update_zone_info(self, zone):
         """Update zone credentials from db"""
-        self.zone_id = zone.id
-        self.name = zone.name
-        self.api_url = zone.api_url
-        self.username = zone.username
-        self.password = zone.password
-        self.weight_offset = zone.weight_offset
-        self.weight_scale = zone.weight_scale
+        self.zone_info = dict(zone.iteritems())
 
     def update_metadata(self, zone_metadata):
         """Update zone metadata after successful communications with
            child zone."""
         self.last_seen = utils.utcnow()
         self.attempt = 0
-        self.capabilities = ", ".join(["%s=%s" % (k, v)
-                        for k, v in zone_metadata.iteritems() if k != 'name'])
+        self.capabilities = dict(
+                [(k, v) for k, v in zone_metadata.iteritems() if k != 'name'])
         self.is_active = True
 
-    def to_dict(self):
-        return dict(name=self.name, capabilities=self.capabilities,
-                    is_active=self.is_active, api_url=self.api_url,
-                    id=self.zone_id, weight_scale=self.weight_scale,
-                    weight_offset=self.weight_offset)
+    def get_zone_info(self):
+        db_fields_to_return = ['api_url', 'id', 'weight_scale',
+                'weight_offset']
+        zone_info = dict(is_active=self.is_active,
+                capabilities=self.capabilities)
+        for field in db_fields_to_return:
+            zone_info[field] = self.zone_info[field]
+        return zone_info
 
     def log_error(self, exception):
         """Something went wrong. Check to see if zone should be
            marked as offline."""
         self.last_exception = exception
         self.last_exception_time = utils.utcnow()
-        api_url = self.api_url
-        logging.warning(_("'%(exception)s' error talking to "
+        api_url = self.zone_info['api_url']
+        LOG.warning(_("'%(exception)s' error talking to "
                           "zone %(api_url)s") % locals())
 
         max_errors = FLAGS.zone_failures_to_offline
         self.attempt += 1
         if self.attempt >= max_errors:
             self.is_active = False
-            logging.error(_("No answer from zone %(api_url)s "
+            LOG.error(_("No answer from zone %(api_url)s "
                             "after %(max_errors)d "
                             "attempts. Marking inactive.") % locals())
 
-
-def _call_novaclient(zone):
-    """Call novaclient. Broken out for testing purposes. Note that
-    we have to use the admin credentials for this since there is no
-    available context."""
-    client = novaclient.Client(zone.username, zone.password, None,
-                               zone.api_url, region_name=zone.name)
-    return client.zones.info()._info
-
-
-def _poll_zone(zone):
-    """Eventlet worker to poll a zone."""
-    name = zone.name
-    url = zone.api_url
-    logging.debug(_("Polling zone: %(name)s @ %(url)s") % locals())
-    try:
-        zone.update_metadata(_call_novaclient(zone))
-    except Exception, e:
-        zone.log_error(traceback.format_exc())
-
-
-class ReadOnlyDict(UserDict.IterableUserDict):
-    """A read-only dict."""
-    def __init__(self, source=None):
-        self.update(source)
-
-    def __setitem__(self, key, item):
-        raise TypeError
-
-    def __delitem__(self, key):
-        raise TypeError
-
-    def clear(self):
-        raise TypeError
-
-    def pop(self, key, *args):
-        raise TypeError
-
-    def popitem(self):
-        raise TypeError
-
-    def update(self, source=None):
-        if source is None:
+    def call_novaclient(self):
+        """Call novaclient. Broken out for testing purposes. Note that
+        we have to use the admin credentials for this since there is no
+        available context."""
+        username = self.zone_info['username']
+        password = self.zone_info['password']
+        api_url = self.zone_info['api_url']
+        region_name = self.zone_info['name']
+        client = novaclient.Client(username, password, None, api_url,
+                region_name)
+        return client.zones.info()._info
+
+    def poll(self):
+        """Eventlet worker to poll a self."""
+        if 'api_url' not in self.zone_info:
             return
-        elif isinstance(source, UserDict.UserDict):
-            self.data = source.data
-        elif isinstance(source, dict):
-            self.data = source
-        else:
-            raise TypeError
-
-
-class HostInfo(object):
-    """Mutable and immutable information on hosts tracked
-    by the ZoneManager. This is an attempt to remove the
-    ad-hoc data structures previously used and lock down
-    access."""
-
-    def __init__(self, host, caps=None, free_ram_mb=0, free_disk_gb=0):
-        self.host = host
-
-        # Read-only capability dicts
-        self.compute = None
-        self.volume = None
-        self.network = None
-
-        if caps:
-            self.compute = ReadOnlyDict(caps.get('compute', None))
-            self.volume = ReadOnlyDict(caps.get('volume', None))
-            self.network = ReadOnlyDict(caps.get('network', None))
-
-        # Mutable available resources.
-        # These will change as resources are virtually "consumed".
-        self.free_ram_mb = free_ram_mb
-        self.free_disk_gb = free_disk_gb
-
-    def consume_resources(self, disk_gb, ram_mb):
-        """Consume some of the mutable resources."""
-        self.free_disk_gb -= disk_gb
-        self.free_ram_mb -= ram_mb
-
-    def __repr__(self):
-        return "%s ram:%s disk:%s" % \
-                    (self.host, self.free_ram_mb, self.free_disk_gb)
+        name = self.zone_info['name']
+        api_url = self.zone_info['api_url']
+        LOG.debug(_("Polling zone: %(name)s @ %(api_url)s") % locals())
+        try:
+            self.update_metadata(self.call_novaclient())
+        except Exception, e:
+            self.log_error(traceback.format_exc())
 
 
 class ZoneManager(object):
@@ -184,116 +117,11 @@ class ZoneManager(object):
     def __init__(self):
         self.last_zone_db_check = datetime.datetime.min
         self.zone_states = {}  # { <zone_id> : ZoneState }
-        self.service_states = {}  # { <host> : { <service> : { cap k : v }}}
         self.green_pool = greenpool.GreenPool()
 
     def get_zone_list(self):
         """Return the list of zones we know about."""
-        return [zone.to_dict() for zone in self.zone_states.values()]
-
-    def get_host_list(self):
-        """Returns a list of dicts for each host that the Zone Manager
-        knows about. Each dict contains the host_name and the service
-        for that host.
-        """
-        all_hosts = self.service_states.keys()
-        ret = []
-        for host in self.service_states:
-            for svc in self.service_states[host]:
-                ret.append({"service": svc, "host_name": host})
-        return ret
-
-    def _compute_node_get_all(self, context):
-        """Broken out for testing."""
-        return db.compute_node_get_all(context)
-
-    def _instance_get_all(self, context):
-        """Broken out for testing."""
-        return db.instance_get_all(context)
-
-    def get_all_host_data(self, context):
-        """Returns a dict of all the hosts the ZoneManager
-        knows about. Also, each of the consumable resources in HostInfo
-        are pre-populated and adjusted based on data in the db.
-
-        For example:
-        {'192.168.1.100': HostInfo(), ...}
-
-        Note: this can be very slow with a lot of instances.
-        InstanceType table isn't required since a copy is stored
-        with the instance (in case the InstanceType changed since the
-        instance was created)."""
-
-        # Make a compute node dict with the bare essential metrics.
-        compute_nodes = self._compute_node_get_all(context)
-        host_info_map = {}
-        for compute in compute_nodes:
-            all_disk = compute['local_gb']
-            all_ram = compute['memory_mb']
-            service = compute['service']
-            if not service:
-                logging.warn(_("No service for compute ID %s") % compute['id'])
-                continue
-
-            host = service['host']
-            caps = self.service_states.get(host, None)
-            host_info = HostInfo(host, caps=caps,
-                    free_disk_gb=all_disk, free_ram_mb=all_ram)
-            # Reserve resources for host/dom0
-            host_info.consume_resources(FLAGS.reserved_host_disk_mb * 1024,
-                    FLAGS.reserved_host_memory_mb)
-            host_info_map[host] = host_info
-
-        # "Consume" resources from the host the instance resides on.
-        instances = self._instance_get_all(context)
-        for instance in instances:
-            host = instance['host']
-            if not host:
-                continue
-            host_info = host_info_map.get(host, None)
-            if not host_info:
-                continue
-            disk = instance['local_gb']
-            ram = instance['memory_mb']
-            host_info.consume_resources(disk, ram)
-
-        return host_info_map
-
-    def get_zone_capabilities(self, context):
-        """Roll up all the individual host info to generic 'service'
-           capabilities. Each capability is aggregated into
-           <cap>_min and <cap>_max values."""
-        hosts_dict = self.service_states
-
-        # TODO(sandy) - be smarter about fabricating this structure.
-        # But it's likely to change once we understand what the Best-Match
-        # code will need better.
-        combined = {}  # { <service>_<cap> : (min, max), ... }
-        stale_host_services = {}  # { host1 : [svc1, svc2], host2 :[svc1]}
-        for host, host_dict in hosts_dict.iteritems():
-            for service_name, service_dict in host_dict.iteritems():
-                if not service_dict.get("enabled", True):
-                    # Service is disabled; do no include it
-                    continue
-
-                #Check if the service capabilities became stale
-                if self.host_service_caps_stale(host, service_name):
-                    if host not in stale_host_services:
-                        stale_host_services[host] = []  # Adding host key once
-                    stale_host_services[host].append(service_name)
-                    continue
-                for cap, value in service_dict.iteritems():
-                    if cap == "timestamp":  # Timestamp is not needed
-                        continue
-                    key = "%s_%s" % (service_name, cap)
-                    min_value, max_value = combined.get(key, (value, value))
-                    min_value = min(min_value, value)
-                    max_value = max(max_value, value)
-                    combined[key] = (min_value, max_value)
-
-        # Delete the expired host services
-        self.delete_expired_host_services(stale_host_services)
-        return combined
+        return [zone.get_zone_info() for zone in self.zone_states.values()]
 
     def _refresh_from_db(self, context):
         """Make our zone state map match the db."""
@@ -302,10 +130,11 @@ class ZoneManager(object):
         existing = self.zone_states.keys()
         db_keys = []
         for zone in zones:
-            db_keys.append(zone.id)
-            if zone.id not in existing:
-                self.zone_states[zone.id] = ZoneState()
-            self.zone_states[zone.id].update_credentials(zone)
+            zone_id = zone['id']
+            db_keys.append(zone_id)
+            if zone_id not in existing:
+                self.zone_states[zone_id] = ZoneState()
+            self.zone_states[zone_id].update_zone_info(zone)
 
         # Cleanup zones removed from db ...
         keys = self.zone_states.keys()  # since we're deleting
@@ -313,42 +142,19 @@ class ZoneManager(object):
             if zone_id not in db_keys:
                 del self.zone_states[zone_id]
 
-    def _poll_zones(self, context):
+    def _poll_zones(self):
         """Try to connect to each child zone and get update."""
-        self.green_pool.imap(_poll_zone, self.zone_states.values())
+        def _worker(zone_state):
+            zone_state.poll()
+        self.green_pool.imap(_worker, self.zone_states.values())
 
-    def ping(self, context):
-        """Ping should be called periodically to update zone status."""
+    def update(self, context):
+        """Update status for all zones.  This should be called
+        periodically to refresh the zone states.
+        """
         diff = utils.utcnow() - self.last_zone_db_check
         if diff.seconds >= FLAGS.zone_db_check_interval:
-            logging.debug(_("Updating zone cache from db."))
+            LOG.debug(_("Updating zone cache from db."))
             self.last_zone_db_check = utils.utcnow()
             self._refresh_from_db(context)
-        self._poll_zones(context)
-
-    def update_service_capabilities(self, service_name, host, capabilities):
-        """Update the per-service capabilities based on this notification."""
-        logging.debug(_("Received %(service_name)s service update from "
-                "%(host)s.") % locals())
-        service_caps = self.service_states.get(host, {})
-        capabilities["timestamp"] = utils.utcnow()  # Reported time
-        service_caps[service_name] = capabilities
-        self.service_states[host] = service_caps
-
-    def host_service_caps_stale(self, host, service):
-        """Check if host service capabilites are not recent enough."""
-        allowed_time_diff = FLAGS.periodic_interval * 3
-        caps = self.service_states[host][service]
-        if (utils.utcnow() - caps["timestamp"]) <= \
-            datetime.timedelta(seconds=allowed_time_diff):
-            return False
-        return True
-
-    def delete_expired_host_services(self, host_services_dict):
-        """Delete all the inactive host services information."""
-        for host, services in host_services_dict.iteritems():
-            service_caps = self.service_states[host]
-            for service in services:
-                del service_caps[service]
-                if len(service_caps) == 0:  # Delete host if no services
-                    del self.service_states[host]
+        self._poll_zones()
diff --git a/nova/tests/scheduler/fake_zone_manager.py b/nova/tests/scheduler/fakes.py
index c1991d9b0..5fb60a206 100644
--- a/nova/tests/scheduler/fake_zone_manager.py
+++ b/nova/tests/scheduler/fakes.py
@@ -13,25 +13,52 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 """
-Fakes For Distributed Scheduler tests.
+Fakes For Scheduler tests.
 """
 
+from nova import db
 from nova.scheduler import distributed_scheduler
+from nova.scheduler import host_manager
 from nova.scheduler import zone_manager
 
 
+COMPUTE_NODES = [
+        dict(id=1, local_gb=1024, memory_mb=1024, service=dict(host='host1')),
+        dict(id=2, local_gb=2048, memory_mb=2048, service=dict(host='host2')),
+        dict(id=3, local_gb=4096, memory_mb=4096, service=dict(host='host3')),
+        dict(id=4, local_gb=8192, memory_mb=8192, service=dict(host='host4')),
+        # Broken entry
+        dict(id=5, local_gb=1024, memory_mb=1024, service=None),
+]
+
+INSTANCES = [
+        dict(local_gb=512, memory_mb=512, host='host1'),
+        dict(local_gb=512, memory_mb=512, host='host2'),
+        dict(local_gb=512, memory_mb=512, host='host2'),
+        dict(local_gb=1024, memory_mb=1024, host='host3'),
+        # Broken host
+        dict(local_gb=1024, memory_mb=1024, host=None),
+        # No matching host
+        dict(local_gb=1024, memory_mb=1024, host='host5'),
+]
+
+
 class FakeDistributedScheduler(distributed_scheduler.DistributedScheduler):
-    # No need to stub anything at the moment
-    pass
+    def __init__(self, *args, **kwargs):
+        super(FakeDistributedScheduler, self).__init__(*args, **kwargs)
+        self.zone_manager = zone_manager.ZoneManager()
+        self.host_manager = host_manager.HostManager()
 
 
-class FakeZoneManager(zone_manager.ZoneManager):
+class FakeHostManager(host_manager.HostManager):
     """host1: free_ram_mb=1024-512-512=0, free_disk_gb=1024-512-512=0
        host2: free_ram_mb=2048-512=1536  free_disk_gb=2048-512=1536
        host3: free_ram_mb=4096-1024=3072  free_disk_gb=4096-1024=3072
        host4: free_ram_mb=8192  free_disk_gb=8192"""
 
     def __init__(self):
+        super(FakeHostManager, self).__init__()
+
         self.service_states = {
             'host1': {
                 'compute': {'host_memory_free': 1073741824},
@@ -55,18 +82,17 @@ class FakeZoneManager(zone_manager.ZoneManager):
             ('host4', dict(free_disk_gb=8192, free_ram_mb=8192)),
         ]
 
-    def _compute_node_get_all(self, context):
-        return [
-            dict(local_gb=1024, memory_mb=1024, service=dict(host='host1')),
-            dict(local_gb=2048, memory_mb=2048, service=dict(host='host2')),
-            dict(local_gb=4096, memory_mb=4096, service=dict(host='host3')),
-            dict(local_gb=8192, memory_mb=8192, service=dict(host='host4')),
-        ]
 
-    def _instance_get_all(self, context):
-        return [
-            dict(local_gb=512, memory_mb=512, host='host1'),
-            dict(local_gb=512, memory_mb=512, host='host1'),
-            dict(local_gb=512, memory_mb=512, host='host2'),
-            dict(local_gb=1024, memory_mb=1024, host='host3'),
-        ]
+class FakeHostState(host_manager.HostState):
+    def __init__(self, host, topic, attribute_dict):
+        super(FakeHostState, self).__init__(host, topic)
+        for (key, val) in attribute_dict.iteritems():
+            setattr(self, key, val)
+
+
+def mox_host_manager_db_calls(mox, context):
+    mox.StubOutWithMock(db, 'compute_node_get_all')
+    mox.StubOutWithMock(db, 'instance_get_all')
+
+    db.compute_node_get_all(context).AndReturn(COMPUTE_NODES)
+    db.instance_get_all(context).AndReturn(INSTANCES)
diff --git a/nova/tests/scheduler/test_distributed_scheduler.py b/nova/tests/scheduler/test_distributed_scheduler.py
index 412c981c5..05c5d18e1 100644
--- a/nova/tests/scheduler/test_distributed_scheduler.py
+++ b/nova/tests/scheduler/test_distributed_scheduler.py
@@ -18,29 +18,15 @@ Tests For Distributed Scheduler.
 
 import json
 
-import nova.db
-
+from nova.compute import api as compute_api
 from nova import context
+from nova import db
 from nova import exception
-from nova import test
 from nova.scheduler import distributed_scheduler
 from nova.scheduler import least_cost
-from nova.scheduler import zone_manager
-from nova.tests.scheduler import fake_zone_manager as ds_fakes
-
-
-class FakeEmptyZoneManager(zone_manager.ZoneManager):
-    def __init__(self):
-        self.service_states = {}
-
-    def get_host_list_from_db(self, context):
-        return []
-
-    def _compute_node_get_all(*args, **kwargs):
-        return []
-
-    def _instance_get_all(*args, **kwargs):
-        return []
+from nova.scheduler import host_manager
+from nova import test
+from nova.tests.scheduler import fakes
 
 
 def fake_call_zone_method(context, method, specs, zones):
@@ -80,8 +66,8 @@ def fake_zone_get_all(context):
     ]
 
 
-def fake_filter_hosts(topic, request_info, unfiltered_hosts, options):
-            return unfiltered_hosts
+def fake_filter_hosts(hosts, filter_properties):
+    return list(hosts)
 
 
 class DistributedSchedulerTestCase(test.TestCase):
@@ -92,7 +78,7 @@ class DistributedSchedulerTestCase(test.TestCase):
         properly adjusted based on the scale/offset in the zone
         db entries.
         """
-        sched = ds_fakes.FakeDistributedScheduler()
+        sched = fakes.FakeDistributedScheduler()
         child_results = fake_call_zone_method(None, None, None, None)
         zones = fake_zone_get_all(None)
         weighted_hosts = sched._adjust_child_weights(child_results, zones)
@@ -113,14 +99,14 @@ class DistributedSchedulerTestCase(test.TestCase):
         def _fake_empty_call_zone_method(*args, **kwargs):
             return []
 
-        sched = ds_fakes.FakeDistributedScheduler()
-        sched.zone_manager = FakeEmptyZoneManager()
+        sched = fakes.FakeDistributedScheduler()
         self.stubs.Set(sched, '_call_zone_method',
                        _fake_empty_call_zone_method)
-        self.stubs.Set(nova.db, 'zone_get_all', fake_zone_get_all)
+        self.stubs.Set(db, 'zone_get_all', fake_zone_get_all)
 
         fake_context = context.RequestContext('user', 'project')
-        request_spec = dict(instance_type=dict(memory_mb=1, local_gb=1))
+        request_spec = {'instance_type': {'memory_mb': 1, 'local_gb': 1},
+                        'instance_properties': {'project_id': 1}}
         self.assertRaises(exception.NoValidHost, sched.schedule_run_instance,
                           fake_context, request_spec)
 
@@ -150,7 +136,7 @@ class DistributedSchedulerTestCase(test.TestCase):
             self.child_zone_called = True
             return 2
 
-        sched = ds_fakes.FakeDistributedScheduler()
+        sched = fakes.FakeDistributedScheduler()
         self.stubs.Set(sched, '_schedule', _fake_schedule)
         self.stubs.Set(sched, '_make_weighted_host_from_blob',
                        _fake_make_weighted_host_from_blob)
@@ -185,7 +171,7 @@ class DistributedSchedulerTestCase(test.TestCase):
             self.was_admin = context.is_admin
             return []
 
-        sched = ds_fakes.FakeDistributedScheduler()
+        sched = fakes.FakeDistributedScheduler()
         self.stubs.Set(sched, '_schedule', fake_schedule)
 
         fake_context = context.RequestContext('user', 'project')
@@ -196,15 +182,16 @@ class DistributedSchedulerTestCase(test.TestCase):
 
     def test_schedule_bad_topic(self):
         """Parameter checking."""
-        sched = ds_fakes.FakeDistributedScheduler()
+        sched = fakes.FakeDistributedScheduler()
         self.assertRaises(NotImplementedError, sched._schedule, None, "foo",
                           {})
 
     def test_schedule_no_instance_type(self):
         """Parameter checking."""
-        sched = ds_fakes.FakeDistributedScheduler()
+        sched = fakes.FakeDistributedScheduler()
+        request_spec = {'instance_properties': {}}
         self.assertRaises(NotImplementedError, sched._schedule, None,
-                          "compute", {})
+                          "compute", request_spec=request_spec)
 
     def test_schedule_happy_day(self):
         """Make sure there's nothing glaringly wrong with _schedule()
@@ -218,26 +205,31 @@ class DistributedSchedulerTestCase(test.TestCase):
             return least_cost.WeightedHost(self.next_weight, host=host,
                                            hostinfo=hostinfo)
 
-        sched = ds_fakes.FakeDistributedScheduler()
-        fake_context = context.RequestContext('user', 'project')
-        sched.zone_manager = ds_fakes.FakeZoneManager()
-        self.stubs.Set(sched, '_filter_hosts', fake_filter_hosts)
+        sched = fakes.FakeDistributedScheduler()
+        fake_context = context.RequestContext('user', 'project',
+                is_admin=True)
+
+        self.stubs.Set(sched.host_manager, 'filter_hosts',
+                fake_filter_hosts)
         self.stubs.Set(least_cost, 'weighted_sum', _fake_weighted_sum)
-        self.stubs.Set(nova.db, 'zone_get_all', fake_zone_get_all)
+        self.stubs.Set(db, 'zone_get_all', fake_zone_get_all)
         self.stubs.Set(sched, '_call_zone_method', fake_call_zone_method)
 
-        instance_type = dict(memory_mb=512, local_gb=512)
-        request_spec = dict(num_instances=10, instance_type=instance_type)
+        request_spec = {'num_instances': 10,
+                        'instance_type': {'memory_mb': 512, 'local_gb': 512},
+                        'instance_properties': {'project_id': 1}}
+        self.mox.ReplayAll()
         weighted_hosts = sched._schedule(fake_context, 'compute',
-                                         request_spec)
+                request_spec)
+        self.mox.VerifyAll()
         self.assertEquals(len(weighted_hosts), 10)
         for weighted_host in weighted_hosts:
             # We set this up so remote hosts have even weights ...
             if int(weighted_host.weight) % 2 == 0:
                 self.assertTrue(weighted_host.zone is not None)
-                self.assertTrue(weighted_host.host is None)
+                self.assertTrue(weighted_host.host_state is None)
             else:
-                self.assertTrue(weighted_host.host is not None)
+                self.assertTrue(weighted_host.host_state is not None)
                 self.assertTrue(weighted_host.zone is None)
 
     def test_schedule_local_zone(self):
@@ -248,33 +240,41 @@ class DistributedSchedulerTestCase(test.TestCase):
 
         def _fake_weighted_sum(functions, hosts, options):
             self.next_weight += 2.0
-            host, hostinfo = hosts[0]
-            return least_cost.WeightedHost(self.next_weight, host=host,
-                                           hostinfo=hostinfo)
+            host = hosts[0]
+            return least_cost.WeightedHost(self.next_weight, host_state=host)
 
-        sched = ds_fakes.FakeDistributedScheduler()
-        fake_context = context.RequestContext('user', 'project')
-        sched.zone_manager = ds_fakes.FakeZoneManager()
-        self.stubs.Set(sched, '_filter_hosts', fake_filter_hosts)
+        sched = fakes.FakeDistributedScheduler()
+        fake_context = context.RequestContext('user', 'project',
+                is_admin=True)
+
+        fakes.mox_host_manager_db_calls(self.mox, fake_context)
+
+        self.stubs.Set(sched.host_manager, 'filter_hosts',
+                fake_filter_hosts)
         self.stubs.Set(least_cost, 'weighted_sum', _fake_weighted_sum)
-        self.stubs.Set(nova.db, 'zone_get_all', fake_zone_get_all)
+        self.stubs.Set(db, 'zone_get_all', fake_zone_get_all)
         self.stubs.Set(sched, '_call_zone_method', fake_call_zone_method)
 
-        instance_type = dict(memory_mb=512, local_gb=512)
-        request_spec = dict(num_instances=10, instance_type=instance_type,
-                            local_zone=True)
+        request_spec = {'num_instances': 10,
+                        'instance_type': {'memory_mb': 512, 'local_gb': 512},
+                        'instance_properties': {'project_id': 1,
+                                                'memory_mb': 512,
+                                                'local_gb': 512},
+                        'local_zone': True}
+        self.mox.ReplayAll()
         weighted_hosts = sched._schedule(fake_context, 'compute',
                                          request_spec)
+        self.mox.VerifyAll()
         self.assertEquals(len(weighted_hosts), 10)
         for weighted_host in weighted_hosts:
             # There should be no remote hosts
-            self.assertTrue(weighted_host.host is not None)
+            self.assertTrue(weighted_host.host_state is not None)
             self.assertTrue(weighted_host.zone is None)
 
     def test_decrypt_blob(self):
         """Test that the decrypt method works."""
 
-        fixture = ds_fakes.FakeDistributedScheduler()
+        fixture = fakes.FakeDistributedScheduler()
         test_data = {'weight': 1, 'host': 'x', 'blob': 'y', 'zone': 'z'}
 
         class StubDecryptor(object):
@@ -290,49 +290,42 @@ class DistributedSchedulerTestCase(test.TestCase):
                          blob='y', zone='z'))
 
     def test_get_cost_functions(self):
-        fixture = ds_fakes.FakeDistributedScheduler()
+        self.flags(reserved_host_memory_mb=128)
+        fixture = fakes.FakeDistributedScheduler()
         fns = fixture.get_cost_functions()
         self.assertEquals(len(fns), 1)
         weight, fn = fns[0]
         self.assertEquals(weight, 1.0)
-        hostinfo = zone_manager.HostInfo('host', free_ram_mb=1000)
-        self.assertEquals(1000, fn(hostinfo))
-
-    def test_filter_hosts_avoid(self):
-        """Test to make sure _filter_hosts() filters original hosts if
-        avoid_original_host is True."""
-
-        def _fake_choose_host_filters():
-            return []
-
-        sched = ds_fakes.FakeDistributedScheduler()
-        fake_context = context.RequestContext('user', 'project')
-        self.stubs.Set(sched, '_choose_host_filters',
-                       _fake_choose_host_filters)
-
-        hosts = [('host1', '1info'), ('host2', '2info'), ('host3', '3info')]
-        request_spec = dict(instance_properties=dict(host='host2'),
-                            avoid_original_host=True)
-
-        filtered = sched._filter_hosts('compute', request_spec, hosts, {})
-        self.assertEqual(filtered,
-                         [('host1', '1info'), ('host3', '3info')])
-
-    def test_filter_hosts_no_avoid(self):
-        """Test to make sure _filter_hosts() does not filter original
-        hosts if avoid_original_host is False."""
-
-        def _fake_choose_host_filters():
-            return []
-
-        sched = ds_fakes.FakeDistributedScheduler()
-        fake_context = context.RequestContext('user', 'project')
-        self.stubs.Set(sched, '_choose_host_filters',
-                       _fake_choose_host_filters)
-
-        hosts = [('host1', '1info'), ('host2', '2info'), ('host3', '3info')]
-        request_spec = dict(instance_properties=dict(host='host2'),
-                            avoid_original_host=False)
-
-        filtered = sched._filter_hosts('compute', request_spec, hosts, {})
-        self.assertEqual(filtered, hosts)
+        hostinfo = host_manager.HostState('host', 'compute')
+        hostinfo.update_from_compute_node(dict(memory_mb=1000,
+                local_gb=0))
+        self.assertEquals(1000 - 128, fn(hostinfo, {}))
+
+    def test_populate_filter_properties(self):
+        request_spec = {'instance_properties': {}}
+        fixture = fakes.FakeDistributedScheduler()
+        filter_properties = {'ignore_hosts': []}
+        fixture.populate_filter_properties(request_spec, filter_properties)
+        self.assertEqual(len(filter_properties['ignore_hosts']), 0)
+
+        # No original host results in not ignoring
+        request_spec = {'instance_properties': {},
+                        'avoid_original_host': True}
+        fixture = fakes.FakeDistributedScheduler()
+        fixture.populate_filter_properties(request_spec, filter_properties)
+        self.assertEqual(len(filter_properties['ignore_hosts']), 0)
+
+        # Original host but avoid is False should not ignore it
+        request_spec = {'instance_properties': {'host': 'foo'},
+                        'avoid_original_host': False}
+        fixture = fakes.FakeDistributedScheduler()
+        fixture.populate_filter_properties(request_spec, filter_properties)
+        self.assertEqual(len(filter_properties['ignore_hosts']), 0)
+
+        # Original host but avoid is True should ignore it
+        request_spec = {'instance_properties': {'host': 'foo'},
+                        'avoid_original_host': True}
+        fixture = fakes.FakeDistributedScheduler()
+        fixture.populate_filter_properties(request_spec, filter_properties)
+        self.assertEqual(len(filter_properties['ignore_hosts']), 1)
+        self.assertEqual(filter_properties['ignore_hosts'][0], 'foo')
diff --git a/nova/tests/scheduler/test_host_filter.py b/nova/tests/scheduler/test_host_filter.py
deleted file mode 100644
index 797ec3fe9..000000000
--- a/nova/tests/scheduler/test_host_filter.py
+++ /dev/null
@@ -1,252 +0,0 @@
-# Copyright 2011 OpenStack LLC.
-# All Rights Reserved.
-#
-#    Licensed under the Apache License, Version 2.0 (the "License"); you may
-#    not use this file except in compliance with the License. You may obtain
-#    a copy of the License at
-#
-#         http://www.apache.org/licenses/LICENSE-2.0
-#
-#    Unless required by applicable law or agreed to in writing, software
-#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
-#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
-#    License for the specific language governing permissions and limitations
-#    under the License.
-"""
-Tests For Scheduler Host Filters.
-"""
-
-import json
-
-import nova
-from nova import exception
-from nova import test
-from nova.scheduler import distributed_scheduler as dist
-from nova.tests.scheduler import fake_zone_manager as ds_fakes
-
-
-class HostFilterTestCase(test.TestCase):
-    """Test case for host filters."""
-
-    def _host_caps(self, multiplier):
-        # Returns host capabilities in the following way:
-        # host1 = memory:free 10 (100max)
-        #         disk:available 100 (1000max)
-        # hostN = memory:free 10 + 10N
-        #         disk:available 100 + 100N
-        # in other words: hostN has more resources than host0
-        # which means ... don't go above 10 hosts.
-        return {'host_name-description': 'XenServer %s' % multiplier,
-                'host_hostname': 'xs-%s' % multiplier,
-                'host_memory_total': 100,
-                'host_memory_overhead': 10,
-                'host_memory_free': 10 + multiplier * 10,
-                'host_memory_free-computed': 10 + multiplier * 10,
-                'host_other-config': {},
-                'host_ip_address': '192.168.1.%d' % (100 + multiplier),
-                'host_cpu_info': {},
-                'disk_available': 100 + multiplier * 100,
-                'disk_total': 1000,
-                'disk_used': 0,
-                'host_uuid': 'xxx-%d' % multiplier,
-                'host_name-label': 'xs-%s' % multiplier,
-                'enabled': True}
-
-    def setUp(self):
-        super(HostFilterTestCase, self).setUp()
-        default_host_filters = ['AllHostsFilter']
-        self.flags(default_host_filters=default_host_filters,
-                reserved_host_disk_mb=0, reserved_host_memory_mb=0)
-        self.instance_type = dict(name='tiny',
-                memory_mb=30,
-                vcpus=10,
-                local_gb=300,
-                flavorid=1,
-                swap=500,
-                rxtx_quota=30000,
-                rxtx_cap=200,
-                extra_specs={})
-        self.gpu_instance_type = dict(name='tiny.gpu',
-                memory_mb=30,
-                vcpus=10,
-                local_gb=300,
-                flavorid=2,
-                swap=500,
-                rxtx_quota=30000,
-                rxtx_cap=200,
-                extra_specs={'xpu_arch': 'fermi',
-                             'xpu_info': 'Tesla 2050'})
-
-        self.zone_manager = ds_fakes.FakeZoneManager()
-        states = {}
-        for x in xrange(4):
-            states['host%d' % (x + 1)] = {'compute': self._host_caps(x)}
-        self.zone_manager.service_states = states
-
-        # Add some extra capabilities to some hosts
-        host4 = self.zone_manager.service_states['host4']['compute']
-        host4['xpu_arch'] = 'fermi'
-        host4['xpu_info'] = 'Tesla 2050'
-
-        host2 = self.zone_manager.service_states['host2']['compute']
-        host2['xpu_arch'] = 'radeon'
-
-        host3 = self.zone_manager.service_states['host3']['compute']
-        host3['xpu_arch'] = 'fermi'
-        host3['xpu_info'] = 'Tesla 2150'
-
-    def _get_all_hosts(self):
-        return self.zone_manager.get_all_host_data(None).items()
-
-    def test_choose_filter(self):
-        # Test default filter ...
-        sched = dist.DistributedScheduler()
-        hfs = sched._choose_host_filters()
-        hf = hfs[0]
-        self.assertEquals(hf._full_name().split(".")[-1], 'AllHostsFilter')
-        # Test valid filter ...
-        hfs = sched._choose_host_filters('InstanceTypeFilter')
-        hf = hfs[0]
-        self.assertEquals(hf._full_name().split(".")[-1], 'InstanceTypeFilter')
-        # Test invalid filter ...
-        try:
-            sched._choose_host_filters('does not exist')
-            self.fail("Should not find host filter.")
-        except exception.SchedulerHostFilterNotFound:
-            pass
-
-    def test_all_host_filter(self):
-        sched = dist.DistributedScheduler()
-        hfs = sched._choose_host_filters('AllHostsFilter')
-        hf = hfs[0]
-        all_hosts = self._get_all_hosts()
-        cooked = hf.instance_type_to_filter(self.instance_type)
-        hosts = hf.filter_hosts(all_hosts, cooked, {})
-        self.assertEquals(4, len(hosts))
-        for host, capabilities in hosts:
-            self.assertTrue(host.startswith('host'))
-
-    def test_instance_type_filter(self):
-        hf = nova.scheduler.filters.InstanceTypeFilter()
-        # filter all hosts that can support 30 ram and 300 disk
-        cooked = hf.instance_type_to_filter(self.instance_type)
-        all_hosts = self._get_all_hosts()
-        hosts = hf.filter_hosts(all_hosts, cooked, {})
-        self.assertEquals(3, len(hosts))
-        just_hosts = [host for host, hostinfo in hosts]
-        just_hosts.sort()
-        self.assertEquals('host4', just_hosts[2])
-        self.assertEquals('host3', just_hosts[1])
-        self.assertEquals('host2', just_hosts[0])
-
-    def test_instance_type_filter_reserved_memory(self):
-        self.flags(reserved_host_memory_mb=2048)
-        hf = nova.scheduler.filters.InstanceTypeFilter()
-        # filter all hosts that can support 30 ram and 300 disk after
-        # reserving 2048 ram
-        cooked = hf.instance_type_to_filter(self.instance_type)
-        all_hosts = self._get_all_hosts()
-        hosts = hf.filter_hosts(all_hosts, cooked, {})
-        self.assertEquals(2, len(hosts))
-        just_hosts = [host for host, hostinfo in hosts]
-        just_hosts.sort()
-        self.assertEquals('host4', just_hosts[1])
-        self.assertEquals('host3', just_hosts[0])
-
-    def test_instance_type_filter_extra_specs(self):
-        hf = nova.scheduler.filters.InstanceTypeFilter()
-        # filter all hosts that can support 30 ram and 300 disk
-        cooked = hf.instance_type_to_filter(self.gpu_instance_type)
-        all_hosts = self._get_all_hosts()
-        hosts = hf.filter_hosts(all_hosts, cooked, {})
-        self.assertEquals(1, len(hosts))
-        just_hosts = [host for host, caps in hosts]
-        self.assertEquals('host4', just_hosts[0])
-
-    def test_json_filter(self):
-        hf = nova.scheduler.filters.JsonFilter()
-        # filter all hosts that can support 30 ram and 300 disk
-        cooked = hf.instance_type_to_filter(self.instance_type)
-        all_hosts = self._get_all_hosts()
-        hosts = hf.filter_hosts(all_hosts, cooked, {})
-        self.assertEquals(2, len(hosts))
-        just_hosts = [host for host, caps in hosts]
-        just_hosts.sort()
-        self.assertEquals('host3', just_hosts[0])
-        self.assertEquals('host4', just_hosts[1])
-
-        # Try some custom queries
-
-        raw = ['or',
-                   ['and',
-                       ['<', '$compute.host_memory_free', 30],
-                       ['<', '$compute.disk_available', 300],
-                   ],
-                   ['and',
-                       ['>', '$compute.host_memory_free', 30],
-                       ['>', '$compute.disk_available', 300],
-                   ]
-              ]
-        cooked = json.dumps(raw)
-        hosts = hf.filter_hosts(all_hosts, cooked, {})
-
-        self.assertEquals(3, len(hosts))
-        just_hosts = [host for host, caps in hosts]
-        just_hosts.sort()
-        for index, host in zip([1, 2, 4], just_hosts):
-            self.assertEquals('host%d' % index, host)
-
-        raw = ['not',
-                  ['=', '$compute.host_memory_free', 30],
-              ]
-        cooked = json.dumps(raw)
-        hosts = hf.filter_hosts(all_hosts, cooked, {})
-
-        self.assertEquals(3, len(hosts))
-        just_hosts = [host for host, caps in hosts]
-        just_hosts.sort()
-        for index, host in zip([1, 2, 4], just_hosts):
-            self.assertEquals('host%d' % index, host)
-
-        raw = ['in', '$compute.host_memory_free', 20, 40, 60, 80, 100]
-        cooked = json.dumps(raw)
-        hosts = hf.filter_hosts(all_hosts, cooked, {})
-        self.assertEquals(2, len(hosts))
-        just_hosts = [host for host, caps in hosts]
-        just_hosts.sort()
-        for index, host in zip([2, 4], just_hosts):
-            self.assertEquals('host%d' % index, host)
-
-        # Try some bogus input ...
-        raw = ['unknown command', ]
-        cooked = json.dumps(raw)
-        try:
-            hf.filter_hosts(all_hosts, cooked, {})
-            self.fail("Should give KeyError")
-        except KeyError, e:
-            pass
-
-        self.assertTrue(hf.filter_hosts(all_hosts, json.dumps([]), {}))
-        self.assertTrue(hf.filter_hosts(all_hosts, json.dumps({}), {}))
-        self.assertTrue(hf.filter_hosts(all_hosts, json.dumps(
-                ['not', True, False, True, False],
-            ), {}))
-
-        try:
-            hf.filter_hosts(all_hosts, json.dumps(
-                'not', True, False, True, False,), {})
-            self.fail("Should give KeyError")
-        except KeyError, e:
-            pass
-
-        self.assertFalse(hf.filter_hosts(all_hosts,
-                json.dumps(['=', '$foo', 100]), {}))
-        self.assertFalse(hf.filter_hosts(all_hosts,
-                json.dumps(['=', '$.....', 100]), {}))
-        self.assertFalse(hf.filter_hosts(all_hosts,
-                json.dumps(
-            ['>', ['and', ['or', ['not', ['<', ['>=', ['<=', ['in', ]]]]]]]]),
-                                                                        {}))
-
-        self.assertFalse(hf.filter_hosts(all_hosts,
-                json.dumps(['=', {}, ['>', '$missing....foo']]), {}))
diff --git a/nova/tests/scheduler/test_host_filters.py b/nova/tests/scheduler/test_host_filters.py
new file mode 100644
index 000000000..40f869902
--- /dev/null
+++ b/nova/tests/scheduler/test_host_filters.py
@@ -0,0 +1,333 @@
+# Copyright 2011 OpenStack LLC.
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+"""
+Tests For Scheduler Host Filters.
+"""
+
+import json
+
+from nova.scheduler import filters
+from nova import test
+from nova.tests.scheduler import fakes
+
+
+class HostFiltersTestCase(test.TestCase):
+    """Test case for host filters."""
+
+    def setUp(self):
+        super(HostFiltersTestCase, self).setUp()
+        self.json_query = json.dumps(
+                ['and', ['>=', '$free_ram_mb', 1024],
+                        ['>=', '$free_disk_mb', 200 * 1024]])
+
+    def test_all_host_filter(self):
+        filt_cls = filters.AllHostsFilter()
+        host = fakes.FakeHostState('host1', 'compute', {})
+        self.assertTrue(filt_cls.host_passes(host, {}))
+
+    def test_compute_filter_passes(self):
+        filt_cls = filters.ComputeFilter()
+        filter_properties = {'instance_type': {'memory_mb': 1024}}
+        capabilities = {'enabled': True}
+        host = fakes.FakeHostState('host1', 'compute',
+                {'free_ram_mb': 1024, 'capabilities': capabilities})
+        self.assertTrue(filt_cls.host_passes(host, filter_properties))
+
+    def test_compute_filter_fails_on_memory(self):
+        filt_cls = filters.ComputeFilter()
+        filter_properties = {'instance_type': {'memory_mb': 1024}}
+        capabilities = {'enabled': True}
+        host = fakes.FakeHostState('host1', 'compute',
+                {'free_ram_mb': 1023, 'capabilities': capabilities})
+        self.assertFalse(filt_cls.host_passes(host, filter_properties))
+
+    def test_compute_filter_fails_on_disabled(self):
+        filt_cls = filters.ComputeFilter()
+        filter_properties = {'instance_type': {'memory_mb': 1024}}
+        capabilities = {'enabled': False}
+        host = fakes.FakeHostState('host1', 'compute',
+                {'free_ram_mb': 1024, 'capabilities': capabilities})
+        self.assertFalse(filt_cls.host_passes(host, filter_properties))
+
+    def test_compute_filter_passes_on_volume(self):
+        filt_cls = filters.ComputeFilter()
+        filter_properties = {'instance_type': {'memory_mb': 1024}}
+        capabilities = {'enabled': False}
+        host = fakes.FakeHostState('host1', 'volume',
+                {'free_ram_mb': 1024, 'capabilities': capabilities})
+        self.assertTrue(filt_cls.host_passes(host, filter_properties))
+
+    def test_compute_filter_passes_on_no_instance_type(self):
+        filt_cls = filters.ComputeFilter()
+        filter_properties = {}
+        capabilities = {'enabled': False}
+        host = fakes.FakeHostState('host1', 'compute',
+                {'free_ram_mb': 1024, 'capabilities': capabilities})
+        self.assertTrue(filt_cls.host_passes(host, filter_properties))
+
+    def test_compute_filter_passes_extra_specs(self):
+        filt_cls = filters.ComputeFilter()
+        extra_specs = {'opt1': 1, 'opt2': 2}
+        capabilities = {'enabled': True, 'opt1': 1, 'opt2': 2}
+        filter_properties = {'instance_type': {'memory_mb': 1024,
+                                               'extra_specs': extra_specs}}
+        host = fakes.FakeHostState('host1', 'compute',
+                {'free_ram_mb': 1024, 'capabilities': capabilities})
+        self.assertTrue(filt_cls.host_passes(host, filter_properties))
+
+    def test_compute_filter_fails_extra_specs(self):
+        filt_cls = filters.ComputeFilter()
+        extra_specs = {'opt1': 1, 'opt2': 3}
+        capabilities = {'enabled': True, 'opt1': 1, 'opt2': 2}
+        filter_properties = {'instance_type': {'memory_mb': 1024,
+                                               'extra_specs': extra_specs}}
+        host = fakes.FakeHostState('host1', 'compute',
+                {'free_ram_mb': 1024, 'capabilities': capabilities})
+        self.assertFalse(filt_cls.host_passes(host, filter_properties))
+
+    def test_json_filter_passes(self):
+        filt_cls = filters.JsonFilter()
+        filter_properties = {'instance_type': {'memory_mb': 1024,
+                                               'local_gb': 200},
+                             'query': self.json_query}
+        capabilities = {'enabled': True}
+        host = fakes.FakeHostState('host1', 'compute',
+                {'free_ram_mb': 1024,
+                 'free_disk_mb': 200 * 1024,
+                 'capabilities': capabilities})
+        self.assertTrue(filt_cls.host_passes(host, filter_properties))
+
+    def test_json_filter_passes_with_no_query(self):
+        filt_cls = filters.JsonFilter()
+        filter_properties = {'instance_type': {'memory_mb': 1024,
+                                               'local_gb': 200}}
+        capabilities = {'enabled': True}
+        host = fakes.FakeHostState('host1', 'compute',
+                {'free_ram_mb': 0,
+                 'free_disk_mb': 0,
+                 'capabilities': capabilities})
+        self.assertTrue(filt_cls.host_passes(host, filter_properties))
+
+    def test_json_filter_fails_on_memory(self):
+        filt_cls = filters.JsonFilter()
+        filter_properties = {'instance_type': {'memory_mb': 1024,
+                                               'local_gb': 200},
+                             'query': self.json_query}
+        capabilities = {'enabled': True}
+        host = fakes.FakeHostState('host1', 'compute',
+                {'free_ram_mb': 1023,
+                 'free_disk_mb': 200 * 1024,
+                 'capabilities': capabilities})
+        self.assertFalse(filt_cls.host_passes(host, filter_properties))
+
+    def test_json_filter_fails_on_disk(self):
+        filt_cls = filters.JsonFilter()
+        filter_properties = {'instance_type': {'memory_mb': 1024,
+                                               'local_gb': 200},
+                             'query': self.json_query}
+        capabilities = {'enabled': True}
+        host = fakes.FakeHostState('host1', 'compute',
+                {'free_ram_mb': 1024,
+                 'free_disk_mb': (200 * 1024) - 1,
+                 'capabilities': capabilities})
+        self.assertFalse(filt_cls.host_passes(host, filter_properties))
+
+    def test_json_filter_fails_on_disk(self):
+        filt_cls = filters.JsonFilter()
+        filter_properties = {'instance_type': {'memory_mb': 1024,
+                                               'local_gb': 200},
+                             'query': self.json_query}
+        capabilities = {'enabled': True}
+        host = fakes.FakeHostState('host1', 'compute',
+                {'free_ram_mb': 1024,
+                 'free_disk_mb': (200 * 1024) - 1,
+                 'capabilities': capabilities})
+        self.assertFalse(filt_cls.host_passes(host, filter_properties))
+
+    def test_json_filter_fails_on_disabled(self):
+        filt_cls = filters.JsonFilter()
+        filter_properties = {'instance_type': {'memory_mb': 1024,
+                                               'local_gb': 200},
+                             'query': self.json_query}
+        capabilities = {'enabled': False}
+        host = fakes.FakeHostState('host1', 'compute',
+                {'free_ram_mb': 1024,
+                 'free_disk_mb': 200 * 1024,
+                 'capabilities': capabilities})
+        self.assertFalse(filt_cls.host_passes(host, filter_properties))
+
+    def test_json_filter_happy_day(self):
+        """Test json filter more thoroughly"""
+        filt_cls = filters.JsonFilter()
+        raw = ['and',
+                  ['=', '$capabilities.opt1', 'match'],
+                  ['or',
+                      ['and',
+                          ['<', '$free_ram_mb', 30],
+                          ['<', '$free_disk_mb', 300]],
+                      ['and',
+                          ['>', '$free_ram_mb', 30],
+                          ['>', '$free_disk_mb', 300]]]]
+        filter_properties = {'query': json.dumps(raw)}
+
+        # Passes
+        capabilities = {'enabled': True, 'opt1': 'match'}
+        host = fakes.FakeHostState('host1', 'compute',
+                {'free_ram_mb': 10,
+                 'free_disk_mb': 200,
+                 'capabilities': capabilities})
+        self.assertTrue(filt_cls.host_passes(host, filter_properties))
+
+        # Passes
+        capabilities = {'enabled': True, 'opt1': 'match'}
+        host = fakes.FakeHostState('host1', 'compute',
+                {'free_ram_mb': 40,
+                 'free_disk_mb': 400,
+                 'capabilities': capabilities})
+        self.assertTrue(filt_cls.host_passes(host, filter_properties))
+
+        # Failes due to disabled
+        capabilities = {'enabled': False, 'opt1': 'match'}
+        host = fakes.FakeHostState('host1', 'instance_type',
+                {'free_ram_mb': 40,
+                 'free_disk_mb': 400,
+                 'capabilities': capabilities})
+        self.assertFalse(filt_cls.host_passes(host, filter_properties))
+
+        # Fails due to being exact memory/disk we don't want
+        capabilities = {'enabled': True, 'opt1': 'match'}
+        host = fakes.FakeHostState('host1', 'compute',
+                {'free_ram_mb': 30,
+                 'free_disk_mb': 300,
+                 'capabilities': capabilities})
+        self.assertFalse(filt_cls.host_passes(host, filter_properties))
+
+        # Fails due to memory lower but disk higher
+        capabilities = {'enabled': True, 'opt1': 'match'}
+        host = fakes.FakeHostState('host1', 'compute',
+                {'free_ram_mb': 20,
+                 'free_disk_mb': 400,
+                 'capabilities': capabilities})
+        self.assertFalse(filt_cls.host_passes(host, filter_properties))
+
+        # Fails due to capabilities 'opt1' not equal
+        capabilities = {'enabled': True, 'opt1': 'no-match'}
+        host = fakes.FakeHostState('host1', 'compute',
+                {'free_ram_mb': 20,
+                 'free_disk_mb': 400,
+                 'capabilities': capabilities})
+        self.assertFalse(filt_cls.host_passes(host, filter_properties))
+
+    def test_json_filter_basic_operators(self):
+        filt_cls = filters.JsonFilter()
+        host = fakes.FakeHostState('host1', 'compute',
+                {'capabilities': {'enabled': True}})
+        # (operator, arguments, expected_result)
+        ops_to_test = [
+                    ['=', [1, 1], True],
+                    ['=', [1, 2], False],
+                    ['<', [1, 2], True],
+                    ['<', [1, 1], False],
+                    ['<', [2, 1], False],
+                    ['>', [2, 1], True],
+                    ['>', [2, 2], False],
+                    ['>', [2, 3], False],
+                    ['<=', [1, 2], True],
+                    ['<=', [1, 1], True],
+                    ['<=', [2, 1], False],
+                    ['>=', [2, 1], True],
+                    ['>=', [2, 2], True],
+                    ['>=', [2, 3], False],
+                    ['in', [1, 1], True],
+                    ['in', [1, 1, 2, 3], True],
+                    ['in', [4, 1, 2, 3], False],
+                    ['not', [True], False],
+                    ['not', [False], True],
+                    ['or', [True, False], True],
+                    ['or', [False, False], False],
+                    ['and', [True, True], True],
+                    ['and', [False, False], False],
+                    ['and', [True, False], False],
+                    # Nested ((True or False) and (2 > 1)) == Passes
+                    ['and', [['or', True, False], ['>', 2, 1]], True]]
+
+        for (op, args, expected) in ops_to_test:
+            raw = [op] + args
+            filter_properties = {'query': json.dumps(raw)}
+            self.assertEqual(expected,
+                    filt_cls.host_passes(host, filter_properties))
+
+        # This results in [False, True, False, True] and if any are True
+        # then it passes...
+        raw = ['not', True, False, True, False]
+        filter_properties = {'query': json.dumps(raw)}
+        self.assertTrue(filt_cls.host_passes(host, filter_properties))
+
+        # This results in [False, False, False] and if any are True
+        # then it passes...which this doesn't
+        raw = ['not', True, True, True]
+        filter_properties = {'query': json.dumps(raw)}
+        self.assertFalse(filt_cls.host_passes(host, filter_properties))
+
+    def test_json_filter_unknown_operator_raises(self):
+        filt_cls = filters.JsonFilter()
+        raw = ['!=', 1, 2]
+        filter_properties = {'query': json.dumps(raw)}
+        capabilities = {'enabled': True, 'opt1': 'no-match'}
+        host = fakes.FakeHostState('host1', 'compute',
+                {'capabilities': {'enabled': True}})
+        self.assertRaises(KeyError,
+                filt_cls.host_passes, host, filter_properties)
+
+    def test_json_filter_empty_filters_pass(self):
+        filt_cls = filters.JsonFilter()
+        capabilities = {'enabled': True, 'opt1': 'no-match'}
+        host = fakes.FakeHostState('host1', 'compute',
+                {'capabilities': {'enabled': True}})
+
+        raw = []
+        filter_properties = {'query': json.dumps(raw)}
+        self.assertTrue(filt_cls.host_passes(host, filter_properties))
+        raw = {}
+        filter_properties = {'query': json.dumps(raw)}
+        self.assertTrue(filt_cls.host_passes(host, filter_properties))
+
+    def test_json_filter_invalid_num_arguments_fails(self):
+        filt_cls = filters.JsonFilter()
+        capabilities = {'enabled': True, 'opt1': 'no-match'}
+        host = fakes.FakeHostState('host1', 'compute',
+                {'capabilities': {'enabled': True}})
+
+        raw = ['>', ['and', ['or', ['not', ['<', ['>=', ['<=', ['in', ]]]]]]]]
+        filter_properties = {'query': json.dumps(raw)}
+        self.assertFalse(filt_cls.host_passes(host, filter_properties))
+
+        raw = ['>', 1]
+        filter_properties = {'query': json.dumps(raw)}
+        self.assertFalse(filt_cls.host_passes(host, filter_properties))
+
+    def test_json_filter_unknown_variable_ignored(self):
+        filt_cls = filters.JsonFilter()
+        capabilities = {'enabled': True, 'opt1': 'no-match'}
+        host = fakes.FakeHostState('host1', 'compute',
+                {'capabilities': {'enabled': True}})
+
+        raw = ['=', '$........', 1, 1]
+        filter_properties = {'query': json.dumps(raw)}
+        self.assertTrue(filt_cls.host_passes(host, filter_properties))
+
+        raw = ['=', '$foo', 2, 2]
+        filter_properties = {'query': json.dumps(raw)}
+        self.assertTrue(filt_cls.host_passes(host, filter_properties))
diff --git a/nova/tests/scheduler/test_host_manager.py b/nova/tests/scheduler/test_host_manager.py
new file mode 100644
index 000000000..ed0fb3d63
--- /dev/null
+++ b/nova/tests/scheduler/test_host_manager.py
@@ -0,0 +1,360 @@
+# Copyright (c) 2011 Openstack, LLC
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+"""
+Tests For HostManager
+"""
+
+import datetime
+
+import mox
+
+from nova import db
+from nova import exception
+from nova import log as logging
+from nova.scheduler import host_manager
+from nova import test
+from nova.tests.scheduler import fakes
+from nova import utils
+
+
+class ComputeFilterClass1(object):
+    def host_passes(self, *args, **kwargs):
+        pass
+
+
+class ComputeFilterClass2(object):
+    def host_passes(self, *args, **kwargs):
+        pass
+
+
+class HostManagerTestCase(test.TestCase):
+    """Test case for HostManager class"""
+
+    def setUp(self):
+        super(HostManagerTestCase, self).setUp()
+        self.host_manager = host_manager.HostManager()
+
+    def test_choose_host_filters_not_found(self):
+        self.flags(default_host_filters='ComputeFilterClass3')
+        self.host_manager.filter_classes = [ComputeFilterClass1,
+                ComputeFilterClass2]
+        self.assertRaises(exception.SchedulerHostFilterNotFound,
+                self.host_manager._choose_host_filters, None)
+
+    def test_choose_host_filters(self):
+        self.flags(default_host_filters=['ComputeFilterClass2'])
+        self.host_manager.filter_classes = [ComputeFilterClass1,
+                ComputeFilterClass2]
+
+        # Test 'compute' returns 1 correct function
+        filter_fns = self.host_manager._choose_host_filters(None)
+        self.assertEqual(len(filter_fns), 1)
+        self.assertEqual(filter_fns[0].__func__,
+                ComputeFilterClass2.host_passes.__func__)
+
+    def test_filter_hosts(self):
+        topic = 'fake_topic'
+
+        filters = ['fake-filter1', 'fake-filter2']
+        fake_host1 = host_manager.HostState('host1', topic)
+        fake_host2 = host_manager.HostState('host2', topic)
+        hosts = [fake_host1, fake_host2]
+        filter_properties = 'fake_properties'
+
+        self.mox.StubOutWithMock(self.host_manager,
+                '_choose_host_filters')
+        self.mox.StubOutWithMock(fake_host1, 'passes_filters')
+        self.mox.StubOutWithMock(fake_host2, 'passes_filters')
+
+        self.host_manager._choose_host_filters(None).AndReturn(filters)
+        fake_host1.passes_filters(filters, filter_properties).AndReturn(
+                False)
+        fake_host2.passes_filters(filters, filter_properties).AndReturn(
+                True)
+
+        self.mox.ReplayAll()
+        filtered_hosts = self.host_manager.filter_hosts(hosts,
+                filter_properties, filters=None)
+        self.mox.VerifyAll()
+        self.assertEqual(len(filtered_hosts), 1)
+        self.assertEqual(filtered_hosts[0], fake_host2)
+
+    def test_update_service_capabilities(self):
+        service_states = self.host_manager.service_states
+        self.assertDictMatch(service_states, {})
+        self.mox.StubOutWithMock(utils, 'utcnow')
+        utils.utcnow().AndReturn(31337)
+        utils.utcnow().AndReturn(31338)
+        utils.utcnow().AndReturn(31339)
+
+        host1_compute_capabs = dict(free_memory=1234, host_memory=5678,
+                timestamp=1)
+        host1_volume_capabs = dict(free_disk=4321, timestamp=1)
+        host2_compute_capabs = dict(free_memory=8756, timestamp=1)
+
+        self.mox.ReplayAll()
+        self.host_manager.update_service_capabilities('compute', 'host1',
+                host1_compute_capabs)
+        self.host_manager.update_service_capabilities('volume', 'host1',
+                host1_volume_capabs)
+        self.host_manager.update_service_capabilities('compute', 'host2',
+                host2_compute_capabs)
+        self.mox.VerifyAll()
+
+        # Make sure dictionary isn't re-assigned
+        self.assertEqual(self.host_manager.service_states, service_states)
+        # Make sure original dictionary wasn't copied
+        self.assertEqual(host1_compute_capabs['timestamp'], 1)
+
+        host1_compute_capabs['timestamp'] = 31337
+        host1_volume_capabs['timestamp'] = 31338
+        host2_compute_capabs['timestamp'] = 31339
+
+        expected = {'host1': {'compute': host1_compute_capabs,
+                              'volume': host1_volume_capabs},
+                    'host2': {'compute': host2_compute_capabs}}
+        self.assertDictMatch(service_states, expected)
+
+    def test_host_service_caps_stale(self):
+        self.flags(periodic_interval=5)
+
+        host1_compute_capabs = dict(free_memory=1234, host_memory=5678,
+                timestamp=datetime.datetime.fromtimestamp(3000))
+        host1_volume_capabs = dict(free_disk=4321,
+                timestamp=datetime.datetime.fromtimestamp(3005))
+        host2_compute_capabs = dict(free_memory=8756,
+                timestamp=datetime.datetime.fromtimestamp(3010))
+
+        service_states = {'host1': {'compute': host1_compute_capabs,
+                                    'volume': host1_volume_capabs},
+                          'host2': {'compute': host2_compute_capabs}}
+
+        self.host_manager.service_states = service_states
+
+        self.mox.StubOutWithMock(utils, 'utcnow')
+        utils.utcnow().AndReturn(datetime.datetime.fromtimestamp(3020))
+        utils.utcnow().AndReturn(datetime.datetime.fromtimestamp(3020))
+        utils.utcnow().AndReturn(datetime.datetime.fromtimestamp(3020))
+
+        self.mox.ReplayAll()
+        res1 = self.host_manager.host_service_caps_stale('host1', 'compute')
+        res2 = self.host_manager.host_service_caps_stale('host1', 'volume')
+        res3 = self.host_manager.host_service_caps_stale('host2', 'compute')
+        self.mox.VerifyAll()
+
+        self.assertEqual(res1, True)
+        self.assertEqual(res2, False)
+        self.assertEqual(res3, False)
+
+    def test_delete_expired_host_services(self):
+        host1_compute_capabs = dict(free_memory=1234, host_memory=5678,
+                timestamp=datetime.datetime.fromtimestamp(3000))
+        host1_volume_capabs = dict(free_disk=4321,
+                timestamp=datetime.datetime.fromtimestamp(3005))
+        host2_compute_capabs = dict(free_memory=8756,
+                timestamp=datetime.datetime.fromtimestamp(3010))
+
+        service_states = {'host1': {'compute': host1_compute_capabs,
+                                    'volume': host1_volume_capabs},
+                          'host2': {'compute': host2_compute_capabs}}
+        self.host_manager.service_states = service_states
+
+        to_delete = {'host1': {'volume': host1_volume_capabs},
+                     'host2': {'compute': host2_compute_capabs}}
+
+        self.host_manager.delete_expired_host_services(to_delete)
+        # Make sure dictionary isn't re-assigned
+        self.assertEqual(self.host_manager.service_states, service_states)
+
+        expected = {'host1': {'compute': host1_compute_capabs}}
+        self.assertEqual(service_states, expected)
+
+    def test_get_service_capabilities(self):
+        host1_compute_capabs = dict(free_memory=1000, host_memory=5678,
+                timestamp=datetime.datetime.fromtimestamp(3000))
+        host1_volume_capabs = dict(free_disk=4321,
+                timestamp=datetime.datetime.fromtimestamp(3005))
+        host2_compute_capabs = dict(free_memory=8756,
+                timestamp=datetime.datetime.fromtimestamp(3010))
+        host2_volume_capabs = dict(free_disk=8756,
+                enabled=False,
+                timestamp=datetime.datetime.fromtimestamp(3010))
+        host3_compute_capabs = dict(free_memory=1234, host_memory=4000,
+                timestamp=datetime.datetime.fromtimestamp(3010))
+        host3_volume_capabs = dict(free_disk=2000,
+                timestamp=datetime.datetime.fromtimestamp(3010))
+
+        service_states = {'host1': {'compute': host1_compute_capabs,
+                                    'volume': host1_volume_capabs},
+                          'host2': {'compute': host2_compute_capabs,
+                                    'volume': host2_volume_capabs},
+                          'host3': {'compute': host3_compute_capabs,
+                                    'volume': host3_volume_capabs}}
+        self.host_manager.service_states = service_states
+
+        info = {'called': 0}
+
+        # This tests with 1 volume disabled (host2), and 1 volume node
+        # as stale (host1)
+        def _fake_host_service_caps_stale(host, service):
+            info['called'] += 1
+            if host == 'host1':
+                if service == 'compute':
+                    return False
+                elif service == 'volume':
+                    return True
+            elif host == 'host2':
+                # Shouldn't get here for 'volume' because the service
+                # is disabled
+                self.assertEqual(service, 'compute')
+                return False
+            self.assertEqual(host, 'host3')
+            return False
+
+        self.stubs.Set(self.host_manager, 'host_service_caps_stale',
+                _fake_host_service_caps_stale)
+
+        self.mox.StubOutWithMock(self.host_manager,
+                'delete_expired_host_services')
+        self.host_manager.delete_expired_host_services({'host1': ['volume']})
+
+        self.mox.ReplayAll()
+        result = self.host_manager.get_service_capabilities()
+        self.mox.VerifyAll()
+
+        self.assertEqual(info['called'], 5)
+
+        # only 1 volume node active == 'host3', so min/max is 2000
+        expected = {'volume_free_disk': (2000, 2000),
+                    'compute_host_memory': (4000, 5678),
+                    'compute_free_memory': (1000, 8756)}
+
+        self.assertDictMatch(result, expected)
+
+    def test_get_all_host_states(self):
+        self.flags(reserved_host_memory_mb=512,
+                reserved_host_disk_mb=1024)
+
+        context = 'fake_context'
+        topic = 'compute'
+
+        self.mox.StubOutWithMock(db, 'compute_node_get_all')
+        self.mox.StubOutWithMock(logging, 'warn')
+        self.mox.StubOutWithMock(db, 'instance_get_all')
+
+        db.compute_node_get_all(context).AndReturn(fakes.COMPUTE_NODES)
+        # Invalid service
+        logging.warn("No service for compute ID 5")
+        db.instance_get_all(context).AndReturn(fakes.INSTANCES)
+
+        self.mox.ReplayAll()
+        host_states = self.host_manager.get_all_host_states(context, topic)
+        self.mox.VerifyAll()
+
+        self.assertEqual(len(host_states), 4)
+        self.assertEqual(host_states['host1'].free_ram_mb, 0)
+        # 511GB
+        self.assertEqual(host_states['host1'].free_disk_mb, 523264)
+        self.assertEqual(host_states['host2'].free_ram_mb, 512)
+        # 1023GB
+        self.assertEqual(host_states['host2'].free_disk_mb, 1047552)
+        self.assertEqual(host_states['host3'].free_ram_mb, 2560)
+        # 3071GB
+        self.assertEqual(host_states['host3'].free_disk_mb, 3144704)
+        self.assertEqual(host_states['host4'].free_ram_mb, 7680)
+        # 8191GB
+        self.assertEqual(host_states['host4'].free_disk_mb, 8387584)
+
+
+class HostStateTestCase(test.TestCase):
+    """Test case for HostState class"""
+
+    def setUp(self):
+        super(HostStateTestCase, self).setUp()
+
+    # update_from_compute_node() and consume_from_instance() are tested
+    # in HostManagerTestCase.test_get_all_host_states()
+
+    def test_host_state_passes_filters_passes(self):
+        fake_host = host_manager.HostState('host1', 'compute')
+        filter_properties = {}
+
+        cls1 = ComputeFilterClass1()
+        cls2 = ComputeFilterClass2()
+        self.mox.StubOutWithMock(cls1, 'host_passes')
+        self.mox.StubOutWithMock(cls2, 'host_passes')
+        filter_fns = [cls1.host_passes, cls2.host_passes]
+
+        cls1.host_passes(fake_host, filter_properties).AndReturn(True)
+        cls2.host_passes(fake_host, filter_properties).AndReturn(True)
+
+        self.mox.ReplayAll()
+        result = fake_host.passes_filters(filter_fns, filter_properties)
+        self.mox.VerifyAll()
+        self.assertTrue(result)
+
+    def test_host_state_passes_filters_passes_with_ignore(self):
+        fake_host = host_manager.HostState('host1', 'compute')
+        filter_properties = {'ignore_hosts': ['host2']}
+
+        cls1 = ComputeFilterClass1()
+        cls2 = ComputeFilterClass2()
+        self.mox.StubOutWithMock(cls1, 'host_passes')
+        self.mox.StubOutWithMock(cls2, 'host_passes')
+        filter_fns = [cls1.host_passes, cls2.host_passes]
+
+        cls1.host_passes(fake_host, filter_properties).AndReturn(True)
+        cls2.host_passes(fake_host, filter_properties).AndReturn(True)
+
+        self.mox.ReplayAll()
+        result = fake_host.passes_filters(filter_fns, filter_properties)
+        self.mox.VerifyAll()
+        self.assertTrue(result)
+
+    def test_host_state_passes_filters_fails(self):
+        fake_host = host_manager.HostState('host1', 'compute')
+        filter_properties = {}
+
+        cls1 = ComputeFilterClass1()
+        cls2 = ComputeFilterClass2()
+        self.mox.StubOutWithMock(cls1, 'host_passes')
+        self.mox.StubOutWithMock(cls2, 'host_passes')
+        filter_fns = [cls1.host_passes, cls2.host_passes]
+
+        cls1.host_passes(fake_host, filter_properties).AndReturn(False)
+        # cls2.host_passes() not called because of short circuit
+
+        self.mox.ReplayAll()
+        result = fake_host.passes_filters(filter_fns, filter_properties)
+        self.mox.VerifyAll()
+        self.assertFalse(result)
+
+    def test_host_state_passes_filters_fails_from_ignore(self):
+        fake_host = host_manager.HostState('host1', 'compute')
+        filter_properties = {'ignore_hosts': ['host1']}
+
+        cls1 = ComputeFilterClass1()
+        cls2 = ComputeFilterClass2()
+        self.mox.StubOutWithMock(cls1, 'host_passes')
+        self.mox.StubOutWithMock(cls2, 'host_passes')
+        filter_fns = [cls1.host_passes, cls2.host_passes]
+
+        # cls[12].host_passes() not called because of short circuit
+        # with matching host to ignore
+
+        self.mox.ReplayAll()
+        result = fake_host.passes_filters(filter_fns, filter_properties)
+        self.mox.VerifyAll()
+        self.assertFalse(result)
diff --git a/nova/tests/scheduler/test_least_cost.py b/nova/tests/scheduler/test_least_cost.py
index 65a4268d3..6b72b026d 100644
--- a/nova/tests/scheduler/test_least_cost.py
+++ b/nova/tests/scheduler/test_least_cost.py
@@ -15,9 +15,10 @@
 """
 Tests For Least Cost functions.
 """
+from nova import context
 from nova.scheduler import least_cost
 from nova import test
-from nova.tests.scheduler import fake_zone_manager
+from nova.tests.scheduler import fakes
 
 
 def offset(hostinfo, options):
@@ -32,38 +33,47 @@ class LeastCostTestCase(test.TestCase):
     def setUp(self):
         super(LeastCostTestCase, self).setUp()
         self.flags(reserved_host_disk_mb=0, reserved_host_memory_mb=0)
-
-        self.zone_manager = fake_zone_manager.FakeZoneManager()
+        self.host_manager = fakes.FakeHostManager()
 
     def tearDown(self):
         super(LeastCostTestCase, self).tearDown()
 
+    def _get_all_hosts(self):
+        ctxt = context.get_admin_context()
+        fakes.mox_host_manager_db_calls(self.mox, ctxt)
+        self.mox.ReplayAll()
+        host_states = self.host_manager.get_all_host_states(ctxt,
+                'compute').values()
+        self.mox.VerifyAll()
+        self.mox.ResetAll()
+        return host_states
+
     def test_weighted_sum_happy_day(self):
         fn_tuples = [(1.0, offset), (1.0, scale)]
-        hostinfo_list = self.zone_manager.get_all_host_data(None).items()
+        hostinfo_list = self._get_all_hosts()
 
-        # host1: free_ram_mb=0
-        # host2: free_ram_mb=1536
+        # host1: free_ram_mb=512
+        # host2: free_ram_mb=1024
         # host3: free_ram_mb=3072
         # host4: free_ram_mb=8192
 
         # [offset, scale]=
-        # [10000, 11536, 13072, 18192]
-        # [0,  768, 1536, 4096]
+        # [10512, 11024, 13072, 18192]
+        # [1024,  2048, 6144, 16384]
 
         # adjusted [ 1.0 * x + 1.0 * y] =
-        # [10000, 12304, 14608, 22288]
+        # [11536, 13072, 19216, 34576]
 
         # so, host1 should win:
         options = {}
         weighted_host = least_cost.weighted_sum(fn_tuples, hostinfo_list,
-                                                                    options)
-        self.assertEqual(weighted_host.weight, 10000)
-        self.assertEqual(weighted_host.host, 'host1')
+                options)
+        self.assertEqual(weighted_host.weight, 11536)
+        self.assertEqual(weighted_host.host_state.host, 'host1')
 
     def test_weighted_sum_single_function(self):
         fn_tuples = [(1.0, offset), ]
-        hostinfo_list = self.zone_manager.get_all_host_data(None).items()
+        hostinfo_list = self._get_all_hosts()
 
         # host1: free_ram_mb=0
         # host2: free_ram_mb=1536
@@ -71,11 +81,11 @@ class LeastCostTestCase(test.TestCase):
         # host4: free_ram_mb=8192
 
         # [offset, ]=
-        # [10000, 11536, 13072, 18192]
+        # [10512, 11024, 13072, 18192]
 
         # so, host1 should win:
         options = {}
         weighted_host = least_cost.weighted_sum(fn_tuples, hostinfo_list,
                                                                     options)
-        self.assertEqual(weighted_host.weight, 10000)
-        self.assertEqual(weighted_host.host, 'host1')
+        self.assertEqual(weighted_host.weight, 10512)
+        self.assertEqual(weighted_host.host_state.host, 'host1')
diff --git a/nova/tests/scheduler/test_zone_manager.py b/nova/tests/scheduler/test_zone_manager.py
new file mode 100644
index 000000000..364384c1c
--- /dev/null
+++ b/nova/tests/scheduler/test_zone_manager.py
@@ -0,0 +1,189 @@
+# Copyright 2010 United States Government as represented by the
+# All Rights Reserved.
+# Copyright 2011 OpenStack LLC
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+"""
+Tests For ZoneManager
+"""
+
+import mox
+
+from nova import db
+from nova import flags
+from nova.scheduler import zone_manager
+from nova import test
+
+FLAGS = flags.FLAGS
+
+
+def _create_zone(zone_id=1, name=None, api_url=None, username=None):
+    if api_url is None:
+        api_url = "http://foo.com"
+    if username is None:
+        username = "user1"
+    if name is None:
+        name = "child1"
+    return dict(id=zone_id, name=name, api_url=api_url,
+            username=username, password="pass1", weight_offset=0.0,
+            weight_scale=1.0)
+
+
+def exploding_novaclient(zone):
+    """Used when we want to simulate a novaclient call failing."""
+    raise Exception("kaboom")
+
+
+class ZoneManagerTestCase(test.TestCase):
+    """Test case for zone manager"""
+
+    zone_manager_cls = zone_manager.ZoneManager
+    zone_state_cls = zone_manager.ZoneState
+
+    def setUp(self):
+        super(ZoneManagerTestCase, self).setUp()
+        self.zone_manager = self.zone_manager_cls()
+
+    def _create_zone_state(self, zone_id=1, name=None, api_url=None,
+            username=None):
+        zone = self.zone_state_cls()
+        zone.zone_info = _create_zone(zone_id, name, api_url, username)
+        return zone
+
+    def test_update(self):
+        zm = self.zone_manager
+        self.mox.StubOutWithMock(zm, '_refresh_from_db')
+        self.mox.StubOutWithMock(zm, '_poll_zones')
+        zm._refresh_from_db(mox.IgnoreArg())
+        zm._poll_zones()
+
+        self.mox.ReplayAll()
+        zm.update(None)
+        self.mox.VerifyAll()
+
+    def test_refresh_from_db_new(self):
+        zone = _create_zone(zone_id=1, username='user1')
+        self.mox.StubOutWithMock(db, 'zone_get_all')
+        db.zone_get_all(mox.IgnoreArg()).AndReturn([zone])
+
+        zm = self.zone_manager
+        self.assertEquals(len(zm.zone_states), 0)
+
+        self.mox.ReplayAll()
+        zm._refresh_from_db(None)
+        self.mox.VerifyAll()
+
+        self.assertEquals(len(zm.zone_states), 1)
+        self.assertIn(1, zm.zone_states)
+        self.assertEquals(zm.zone_states[1].zone_info['username'], 'user1')
+
+    def test_refresh_from_db_replace_existing(self):
+        zone_state = self._create_zone_state(zone_id=1, username='user1')
+        zm = self.zone_manager
+        zm.zone_states[1] = zone_state
+
+        zone = _create_zone(zone_id=1, username='user2')
+        self.mox.StubOutWithMock(db, 'zone_get_all')
+        db.zone_get_all(mox.IgnoreArg()).AndReturn([zone])
+        self.assertEquals(len(zm.zone_states), 1)
+
+        self.mox.ReplayAll()
+        zm._refresh_from_db(None)
+        self.mox.VerifyAll()
+
+        self.assertEquals(len(zm.zone_states), 1)
+        self.assertEquals(zm.zone_states[1].zone_info['username'], 'user2')
+
+    def test_refresh_from_db_missing(self):
+        zone_state = self._create_zone_state(zone_id=1, username='user1')
+        zm = self.zone_manager
+        zm.zone_states[1] = zone_state
+
+        self.mox.StubOutWithMock(db, 'zone_get_all')
+        db.zone_get_all(mox.IgnoreArg()).AndReturn([])
+
+        self.assertEquals(len(zm.zone_states), 1)
+
+        self.mox.ReplayAll()
+        zm._refresh_from_db(None)
+        self.mox.VerifyAll()
+
+        self.assertEquals(len(zm.zone_states), 0)
+
+    def test_refresh_from_db_add(self):
+        zone_state = self._create_zone_state(zone_id=1, username='user1')
+        zm = self.zone_manager
+        zm.zone_states[1] = zone_state
+
+        zone1 = _create_zone(zone_id=1, username='user1')
+        zone2 = _create_zone(zone_id=2, username='user2')
+        self.mox.StubOutWithMock(db, 'zone_get_all')
+        db.zone_get_all(mox.IgnoreArg()).AndReturn([zone1, zone2])
+
+        self.mox.ReplayAll()
+        zm._refresh_from_db(None)
+        self.mox.VerifyAll()
+
+        self.assertEquals(len(zm.zone_states), 2)
+        self.assertIn(1, zm.zone_states)
+        self.assertIn(2, zm.zone_states)
+        self.assertEquals(zm.zone_states[1].zone_info['username'], 'user1')
+        self.assertEquals(zm.zone_states[2].zone_info['username'], 'user2')
+
+    def test_refresh_from_db_add_and_delete(self):
+        zone_state = self._create_zone_state(zone_id=1, username='user1')
+        zm = self.zone_manager
+        zm.zone_states[1] = zone_state
+
+        zone2 = _create_zone(zone_id=2, username='user2')
+        self.mox.StubOutWithMock(db, 'zone_get_all')
+        db.zone_get_all(mox.IgnoreArg()).AndReturn([zone2])
+
+        self.mox.ReplayAll()
+        zm._refresh_from_db(None)
+        self.mox.VerifyAll()
+
+        self.assertEquals(len(zm.zone_states), 1)
+        self.assertIn(2, zm.zone_states)
+        self.assertEquals(zm.zone_states[2].zone_info['username'], 'user2')
+
+    def test_poll_zone(self):
+        zone_state = self._create_zone_state(zone_id=1, name='child1')
+        zone_state.attempt = 1
+
+        self.mox.StubOutWithMock(zone_state, 'call_novaclient')
+        zone_state.call_novaclient().AndReturn(
+                dict(name=zone_state.zone_info['name'],
+                        hairdresser='dietz'))
+        self.assertDictMatch(zone_state.capabilities, {})
+
+        self.mox.ReplayAll()
+        zone_state.poll()
+        self.mox.VerifyAll()
+        self.assertEquals(zone_state.attempt, 0)
+        self.assertDictMatch(zone_state.capabilities,
+                dict(hairdresser='dietz'))
+        self.assertTrue(zone_state.is_active)
+
+    def test_poll_zones_with_failure(self):
+        zone_state = self._create_zone_state(zone_id=1)
+        zone_state.attempt = FLAGS.zone_failures_to_offline - 1
+
+        self.mox.StubOutWithMock(zone_state, 'call_novaclient')
+        zone_state.call_novaclient().AndRaise(Exception('foo'))
+
+        self.mox.ReplayAll()
+        zone_state.poll()
+        self.mox.VerifyAll()
+        self.assertEquals(zone_state.attempt, 3)
+        self.assertFalse(zone_state.is_active)
diff --git a/nova/tests/test_zones.py b/nova/tests/test_zones.py
deleted file mode 100644
index 703ff0bf9..000000000
--- a/nova/tests/test_zones.py
+++ /dev/null
@@ -1,377 +0,0 @@
-# Copyright 2010 United States Government as represented by the
-# All Rights Reserved.
-#
-#    Licensed under the Apache License, Version 2.0 (the "License"); you may
-#    not use this file except in compliance with the License. You may obtain
-#    a copy of the License at
-#
-#         http://www.apache.org/licenses/LICENSE-2.0
-#
-#    Unless required by applicable law or agreed to in writing, software
-#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
-#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
-#    License for the specific language governing permissions and limitations
-#    under the License.
-"""
-Tests For ZoneManager
-"""
-
-import datetime
-import mox
-
-from nova import db
-from nova import flags
-from nova import test
-from nova import utils
-from nova.scheduler import zone_manager
-
-FLAGS = flags.FLAGS
-
-
-class FakeZone:
-    """Represents a fake zone from the db"""
-    def __init__(self, *args, **kwargs):
-        for k, v in kwargs.iteritems():
-            setattr(self, k, v)
-
-
-def exploding_novaclient(zone):
-    """Used when we want to simulate a novaclient call failing."""
-    raise Exception("kaboom")
-
-
-class ZoneManagerTestCase(test.TestCase):
-    """Test case for zone manager"""
-    def test_ping(self):
-        zm = zone_manager.ZoneManager()
-        self.mox.StubOutWithMock(zm, '_refresh_from_db')
-        self.mox.StubOutWithMock(zm, '_poll_zones')
-        zm._refresh_from_db(mox.IgnoreArg())
-        zm._poll_zones(mox.IgnoreArg())
-
-        self.mox.ReplayAll()
-        zm.ping(None)
-        self.mox.VerifyAll()
-
-    def test_refresh_from_db_new(self):
-        zm = zone_manager.ZoneManager()
-
-        self.mox.StubOutWithMock(db, 'zone_get_all')
-        db.zone_get_all(mox.IgnoreArg()).AndReturn([
-               FakeZone(id=1, api_url='http://foo.com', username='user1',
-                    password='pass1', name='child', weight_offset=0.0,
-                    weight_scale=1.0),
-            ])
-
-        self.assertEquals(len(zm.zone_states), 0)
-
-        self.mox.ReplayAll()
-        zm._refresh_from_db(None)
-        self.mox.VerifyAll()
-
-        self.assertEquals(len(zm.zone_states), 1)
-        self.assertEquals(zm.zone_states[1].username, 'user1')
-
-    def test_service_capabilities(self):
-        zm = zone_manager.ZoneManager()
-        caps = zm.get_zone_capabilities(None)
-        self.assertEquals(caps, {})
-
-        zm.update_service_capabilities("svc1", "host1", dict(a=1, b=2))
-        caps = zm.get_zone_capabilities(None)
-        self.assertEquals(caps, dict(svc1_a=(1, 1), svc1_b=(2, 2)))
-
-        zm.update_service_capabilities("svc1", "host1", dict(a=2, b=3))
-        caps = zm.get_zone_capabilities(None)
-        self.assertEquals(caps, dict(svc1_a=(2, 2), svc1_b=(3, 3)))
-
-        zm.update_service_capabilities("svc1", "host2", dict(a=20, b=30))
-        caps = zm.get_zone_capabilities(None)
-        self.assertEquals(caps, dict(svc1_a=(2, 20), svc1_b=(3, 30)))
-
-        zm.update_service_capabilities("svc10", "host1", dict(a=99, b=99))
-        caps = zm.get_zone_capabilities(None)
-        self.assertEquals(caps, dict(svc1_a=(2, 20), svc1_b=(3, 30),
-                                     svc10_a=(99, 99), svc10_b=(99, 99)))
-
-        zm.update_service_capabilities("svc1", "host3", dict(c=5))
-        caps = zm.get_zone_capabilities(None)
-        self.assertEquals(caps, dict(svc1_a=(2, 20), svc1_b=(3, 30),
-                                     svc1_c=(5, 5), svc10_a=(99, 99),
-                                     svc10_b=(99, 99)))
-
-    def test_refresh_from_db_replace_existing(self):
-        zm = zone_manager.ZoneManager()
-        zone_state = zone_manager.ZoneState()
-        zone_state.update_credentials(FakeZone(id=1, api_url='http://foo.com',
-                        username='user1', password='pass1', name='child',
-                        weight_offset=0.0, weight_scale=1.0))
-        zm.zone_states[1] = zone_state
-
-        self.mox.StubOutWithMock(db, 'zone_get_all')
-        db.zone_get_all(mox.IgnoreArg()).AndReturn([
-               FakeZone(id=1, api_url='http://foo.com', username='user2',
-                    password='pass2', name='child',
-                    weight_offset=0.0, weight_scale=1.0),
-            ])
-
-        self.assertEquals(len(zm.zone_states), 1)
-
-        self.mox.ReplayAll()
-        zm._refresh_from_db(None)
-        self.mox.VerifyAll()
-
-        self.assertEquals(len(zm.zone_states), 1)
-        self.assertEquals(zm.zone_states[1].username, 'user2')
-
-    def test_refresh_from_db_missing(self):
-        zm = zone_manager.ZoneManager()
-        zone_state = zone_manager.ZoneState()
-        zone_state.update_credentials(FakeZone(id=1, api_url='http://foo.com',
-                        username='user1', password='pass1', name='child',
-                        weight_offset=0.0, weight_scale=1.0))
-        zm.zone_states[1] = zone_state
-
-        self.mox.StubOutWithMock(db, 'zone_get_all')
-        db.zone_get_all(mox.IgnoreArg()).AndReturn([])
-
-        self.assertEquals(len(zm.zone_states), 1)
-
-        self.mox.ReplayAll()
-        zm._refresh_from_db(None)
-        self.mox.VerifyAll()
-
-        self.assertEquals(len(zm.zone_states), 0)
-
-    def test_refresh_from_db_add_and_delete(self):
-        zm = zone_manager.ZoneManager()
-        zone_state = zone_manager.ZoneState()
-        zone_state.update_credentials(FakeZone(id=1, api_url='http://foo.com',
-                        username='user1', password='pass1', name='child',
-                        weight_offset=2.0, weight_scale=3.0))
-        zm.zone_states[1] = zone_state
-
-        self.mox.StubOutWithMock(db, 'zone_get_all')
-
-        db.zone_get_all(mox.IgnoreArg()).AndReturn([
-               FakeZone(id=2, api_url='http://foo.com', username='user2',
-                    password='pass2', name='child', weight_offset=2.0,
-                    weight_scale=3.0),
-            ])
-        self.assertEquals(len(zm.zone_states), 1)
-
-        self.mox.ReplayAll()
-        zm._refresh_from_db(None)
-        self.mox.VerifyAll()
-
-        self.assertEquals(len(zm.zone_states), 1)
-        self.assertEquals(zm.zone_states[2].username, 'user2')
-
-    def test_poll_zone(self):
-        self.mox.StubOutWithMock(zone_manager, '_call_novaclient')
-        zone_manager._call_novaclient(mox.IgnoreArg()).AndReturn(
-                        dict(name='child', capabilities='hairdresser'))
-
-        zone_state = zone_manager.ZoneState()
-        zone_state.update_credentials(FakeZone(id=2,
-                       api_url='http://foo.com', username='user2',
-                       password='pass2', name='child',
-                        weight_offset=0.0, weight_scale=1.0))
-        zone_state.attempt = 1
-
-        self.mox.ReplayAll()
-        zone_manager._poll_zone(zone_state)
-        self.mox.VerifyAll()
-        self.assertEquals(zone_state.attempt, 0)
-        self.assertEquals(zone_state.name, 'child')
-
-    def test_poll_zone_fails(self):
-        self.stubs.Set(zone_manager, "_call_novaclient", exploding_novaclient)
-
-        zone_state = zone_manager.ZoneState()
-        zone_state.update_credentials(FakeZone(id=2,
-                       api_url='http://foo.com', username='user2',
-                       password='pass2', name='child',
-                       weight_offset=0.0, weight_scale=1.0))
-        zone_state.attempt = FLAGS.zone_failures_to_offline - 1
-
-        self.mox.ReplayAll()
-        zone_manager._poll_zone(zone_state)
-        self.mox.VerifyAll()
-        self.assertEquals(zone_state.attempt, 3)
-        self.assertFalse(zone_state.is_active)
-
-    def test_host_service_caps_stale_no_stale_service(self):
-        zm = zone_manager.ZoneManager()
-
-        # services just updated capabilities
-        zm.update_service_capabilities("svc1", "host1", dict(a=1, b=2))
-        zm.update_service_capabilities("svc2", "host1", dict(a=3, b=4))
-        self.assertFalse(zm.host_service_caps_stale("host1", "svc1"))
-        self.assertFalse(zm.host_service_caps_stale("host1", "svc2"))
-
-    def test_host_service_caps_stale_all_stale_services(self):
-        zm = zone_manager.ZoneManager()
-        expiry_time = (FLAGS.periodic_interval * 3) + 1
-
-        # Both services became stale
-        zm.update_service_capabilities("svc1", "host1", dict(a=1, b=2))
-        zm.update_service_capabilities("svc2", "host1", dict(a=3, b=4))
-        time_future = utils.utcnow() + datetime.timedelta(seconds=expiry_time)
-        utils.set_time_override(time_future)
-        self.assertTrue(zm.host_service_caps_stale("host1", "svc1"))
-        self.assertTrue(zm.host_service_caps_stale("host1", "svc2"))
-        utils.clear_time_override()
-
-    def test_host_service_caps_stale_one_stale_service(self):
-        zm = zone_manager.ZoneManager()
-        expiry_time = (FLAGS.periodic_interval * 3) + 1
-
-        # One service became stale
-        zm.update_service_capabilities("svc1", "host1", dict(a=1, b=2))
-        zm.update_service_capabilities("svc2", "host1", dict(a=3, b=4))
-        caps = zm.service_states["host1"]["svc1"]
-        caps["timestamp"] = utils.utcnow() - \
-                               datetime.timedelta(seconds=expiry_time)
-        self.assertTrue(zm.host_service_caps_stale("host1", "svc1"))
-        self.assertFalse(zm.host_service_caps_stale("host1", "svc2"))
-
-    def test_delete_expired_host_services_del_one_service(self):
-        zm = zone_manager.ZoneManager()
-
-        # Delete one service in a host
-        zm.update_service_capabilities("svc1", "host1", dict(a=1, b=2))
-        zm.update_service_capabilities("svc2", "host1", dict(a=3, b=4))
-        stale_host_services = {"host1": ["svc1"]}
-        zm.delete_expired_host_services(stale_host_services)
-        self.assertFalse("svc1" in zm.service_states["host1"])
-        self.assertTrue("svc2" in zm.service_states["host1"])
-
-    def test_delete_expired_host_services_del_all_hosts(self):
-        zm = zone_manager.ZoneManager()
-
-        # Delete all services in a host
-        zm.update_service_capabilities("svc2", "host1", dict(a=3, b=4))
-        zm.update_service_capabilities("svc1", "host1", dict(a=1, b=2))
-        stale_host_services = {"host1": ["svc1", "svc2"]}
-        zm.delete_expired_host_services(stale_host_services)
-        self.assertFalse("host1" in zm.service_states)
-
-    def test_delete_expired_host_services_del_one_service_per_host(self):
-        zm = zone_manager.ZoneManager()
-
-        # Delete one service per host
-        zm.update_service_capabilities("svc1", "host1", dict(a=1, b=2))
-        zm.update_service_capabilities("svc1", "host2", dict(a=3, b=4))
-        stale_host_services = {"host1": ["svc1"], "host2": ["svc1"]}
-        zm.delete_expired_host_services(stale_host_services)
-        self.assertFalse("host1" in zm.service_states)
-        self.assertFalse("host2" in zm.service_states)
-
-    def test_get_zone_capabilities_one_host(self):
-        zm = zone_manager.ZoneManager()
-
-        # Service capabilities recent
-        zm.update_service_capabilities("svc1", "host1", dict(a=1, b=2))
-        caps = zm.get_zone_capabilities(None)
-        self.assertEquals(caps, dict(svc1_a=(1, 1), svc1_b=(2, 2)))
-
-    def test_get_zone_capabilities_expired_host(self):
-        zm = zone_manager.ZoneManager()
-        expiry_time = (FLAGS.periodic_interval * 3) + 1
-
-        # Service capabilities stale
-        zm.update_service_capabilities("svc1", "host1", dict(a=1, b=2))
-        time_future = utils.utcnow() + datetime.timedelta(seconds=expiry_time)
-        utils.set_time_override(time_future)
-        caps = zm.get_zone_capabilities(None)
-        self.assertEquals(caps, {})
-        utils.clear_time_override()
-
-    def test_get_zone_capabilities_multiple_hosts(self):
-        zm = zone_manager.ZoneManager()
-
-        # Both host service capabilities recent
-        zm.update_service_capabilities("svc1", "host1", dict(a=1, b=2))
-        zm.update_service_capabilities("svc1", "host2", dict(a=3, b=4))
-        caps = zm.get_zone_capabilities(None)
-        self.assertEquals(caps, dict(svc1_a=(1, 3), svc1_b=(2, 4)))
-
-    def test_get_zone_capabilities_one_stale_host(self):
-        zm = zone_manager.ZoneManager()
-        expiry_time = (FLAGS.periodic_interval * 3) + 1
-
-        # One host service capabilities become stale
-        zm.update_service_capabilities("svc1", "host1", dict(a=1, b=2))
-        zm.update_service_capabilities("svc1", "host2", dict(a=3, b=4))
-        serv_caps = zm.service_states["host1"]["svc1"]
-        serv_caps["timestamp"] = utils.utcnow() - \
-                               datetime.timedelta(seconds=expiry_time)
-        caps = zm.get_zone_capabilities(None)
-        self.assertEquals(caps, dict(svc1_a=(3, 3), svc1_b=(4, 4)))
-
-    def test_get_zone_capabilities_multiple_service_per_host(self):
-        zm = zone_manager.ZoneManager()
-
-        # Multiple services per host
-        zm.update_service_capabilities("svc1", "host1", dict(a=1, b=2))
-        zm.update_service_capabilities("svc1", "host2", dict(a=3, b=4))
-        zm.update_service_capabilities("svc2", "host1", dict(a=5, b=6))
-        zm.update_service_capabilities("svc2", "host2", dict(a=7, b=8))
-        caps = zm.get_zone_capabilities(None)
-        self.assertEquals(caps, dict(svc1_a=(1, 3), svc1_b=(2, 4),
-                                     svc2_a=(5, 7), svc2_b=(6, 8)))
-
-    def test_get_zone_capabilities_one_stale_service_per_host(self):
-        zm = zone_manager.ZoneManager()
-        expiry_time = (FLAGS.periodic_interval * 3) + 1
-
-        # Two host services among four become stale
-        zm.update_service_capabilities("svc1", "host1", dict(a=1, b=2))
-        zm.update_service_capabilities("svc1", "host2", dict(a=3, b=4))
-        zm.update_service_capabilities("svc2", "host1", dict(a=5, b=6))
-        zm.update_service_capabilities("svc2", "host2", dict(a=7, b=8))
-        serv_caps_1 = zm.service_states["host1"]["svc2"]
-        serv_caps_1["timestamp"] = utils.utcnow() - \
-                               datetime.timedelta(seconds=expiry_time)
-        serv_caps_2 = zm.service_states["host2"]["svc1"]
-        serv_caps_2["timestamp"] = utils.utcnow() - \
-                               datetime.timedelta(seconds=expiry_time)
-        caps = zm.get_zone_capabilities(None)
-        self.assertEquals(caps, dict(svc1_a=(1, 1), svc1_b=(2, 2),
-                                     svc2_a=(7, 7), svc2_b=(8, 8)))
-
-    def test_get_zone_capabilities_three_stale_host_services(self):
-        zm = zone_manager.ZoneManager()
-        expiry_time = (FLAGS.periodic_interval * 3) + 1
-
-        # Three host services among four become stale
-        zm.update_service_capabilities("svc1", "host1", dict(a=1, b=2))
-        zm.update_service_capabilities("svc1", "host2", dict(a=3, b=4))
-        zm.update_service_capabilities("svc2", "host1", dict(a=5, b=6))
-        zm.update_service_capabilities("svc2", "host2", dict(a=7, b=8))
-        serv_caps_1 = zm.service_states["host1"]["svc2"]
-        serv_caps_1["timestamp"] = utils.utcnow() - \
-                               datetime.timedelta(seconds=expiry_time)
-        serv_caps_2 = zm.service_states["host2"]["svc1"]
-        serv_caps_2["timestamp"] = utils.utcnow() - \
-                               datetime.timedelta(seconds=expiry_time)
-        serv_caps_3 = zm.service_states["host2"]["svc2"]
-        serv_caps_3["timestamp"] = utils.utcnow() - \
-                               datetime.timedelta(seconds=expiry_time)
-        caps = zm.get_zone_capabilities(None)
-        self.assertEquals(caps, dict(svc1_a=(1, 1), svc1_b=(2, 2)))
-
-    def test_get_zone_capabilities_all_stale_host_services(self):
-        zm = zone_manager.ZoneManager()
-        expiry_time = (FLAGS.periodic_interval * 3) + 1
-
-        # All the host services  become stale
-        zm.update_service_capabilities("svc1", "host1", dict(a=1, b=2))
-        zm.update_service_capabilities("svc1", "host2", dict(a=3, b=4))
-        zm.update_service_capabilities("svc2", "host1", dict(a=5, b=6))
-        zm.update_service_capabilities("svc2", "host2", dict(a=7, b=8))
-        time_future = utils.utcnow() + datetime.timedelta(seconds=expiry_time)
-        utils.set_time_override(time_future)
-        caps = zm.get_zone_capabilities(None)
-        self.assertEquals(caps, {})