Poll instance states periodically, so that we can detect when something changes 'behind the scenes'.

Beginnings of work on Bug #661214 and Bug #661260.

11 files changed, 442 insertions, 23 deletions

diff --git a/nova/compute/manager.py b/nova/compute/manager.py
index 09af03564..9591a6c19 100644
--- a/nova/compute/manager.py
+++ b/nova/compute/manager.py
@@ -2,6 +2,7 @@
 
 # Copyright 2010 United States Government as represented by the
 # Administrator of the National Aeronautics and Space Administration.
+# Copyright 2011 Justin Santa Barbara
 # All Rights Reserved.
 #
 #    Licensed under the Apache License, Version 2.0 (the "License"); you may
@@ -51,6 +52,7 @@ from nova import manager
 from nova import rpc
 from nova import utils
 from nova.compute import power_state
+from nova.virt import driver
 
 FLAGS = flags.FLAGS
 flags.DEFINE_string('instances_path', '$state_path/instances',
@@ -120,7 +122,9 @@ class ComputeManager(manager.Manager):
             compute_driver = FLAGS.compute_driver
 
         try:
-            self.driver = utils.import_object(compute_driver)
+            self.driver = utils.check_isinstance(
+                                        utils.import_object(compute_driver),
+                                        driver.ComputeDriver)
         except ImportError as e:
             LOG.error(_("Unable to load the virtualization driver: %s") % (e))
             sys.exit(1)
@@ -1016,3 +1020,59 @@ class ComputeManager(manager.Manager):
 
         for volume in instance_ref['volumes']:
             self.db.volume_update(ctxt, volume['id'], {'status': 'in-use'})
+
+    def periodic_tasks(self, context=None):
+        """Tasks to be run at a periodic interval."""
+        error_list = super(ComputeManager, self).periodic_tasks(context)
+        if error_list is None:
+            error_list = []
+
+        try:
+            self._poll_instance_states(context)
+        except Exception as ex:
+            LOG.warning(_("Error during instance poll: %s"),
+                        unicode(ex))
+            error_list.append(ex)
+        return error_list
+
+    def _poll_instance_states(self, context):
+        vm_instances = self.driver.list_instances_detail()
+        vm_instances = dict((vm.name, vm) for vm in vm_instances)
+
+        # Keep a list of VMs not in the DB, cross them off as we find them
+        vms_not_found_in_db = list(vm_instances.keys())
+
+        db_instances = self.db.instance_get_all_by_host(context, self.host)
+
+        for db_instance in db_instances:
+            name = db_instance['name']
+            vm_instance = vm_instances.get(name)
+            if vm_instance is None:
+                LOG.info(_("Found instance '%(name)s' in DB but no VM. "
+                           "Setting state to shutoff.") % locals())
+                vm_state = power_state.SHUTOFF
+            else:
+                vm_state = vm_instance.state
+                vms_not_found_in_db.remove(name)
+
+            db_state = db_instance['state']
+            if vm_state != db_state:
+                LOG.info(_("DB/VM state mismatch. Changing state from "
+                           "'%(db_state)s' to '%(vm_state)s'") % locals())
+                self.db.instance_set_state(context,
+                                           db_instance['id'],
+                                           vm_state)
+
+            if vm_state == power_state.SHUTOFF:
+                # TODO(soren): This is what the compute manager does when you
+                # terminate an instance. At some point I figure we'll have a
+                # "terminated" state and some sort of cleanup job that runs
+                # occasionally, cleaning them out.
+                self.db.instance_destroy(context, db_instance['id'])
+
+        # Are there VMs not in the DB?
+        for vm_not_found_in_db in vms_not_found_in_db:
+            name = vm_not_found_in_db
+            # TODO(justinsb): What to do here?  Adopt it?  Shut it down?
+            LOG.warning(_("Found VM not in DB: '%(name)s'.  Ignoring")
+                        % locals())
diff --git a/nova/compute/power_state.py b/nova/compute/power_state.py
index adfc2dff0..ef013b2ef 100644
--- a/nova/compute/power_state.py
+++ b/nova/compute/power_state.py
@@ -2,6 +2,7 @@
 
 # Copyright 2010 United States Government as represented by the
 # Administrator of the National Aeronautics and Space Administration.
+# Copyright 2011 Justin Santa Barbara
 # All Rights Reserved.
 # Copyright (c) 2010 Citrix Systems, Inc.
 #
@@ -19,6 +20,7 @@
 
 """The various power states that a VM can be in."""
 
+#NOTE(justinsb): These are the virDomainState values from libvirt
 NOSTATE = 0x00
 RUNNING = 0x01
 BLOCKED = 0x02
@@ -29,9 +31,10 @@ CRASHED = 0x06
 SUSPENDED = 0x07
 FAILED = 0x08
 
-
-def name(code):
-    d = {
+# TODO(justinsb): Power state really needs to be a proper class,
+# so that we're not locked into the libvirt status codes and can put mapping
+# logic here rather than spread throughout the code
+_STATE_MAP = {
         NOSTATE: 'pending',
         RUNNING: 'running',
         BLOCKED: 'blocked',
@@ -41,4 +44,11 @@ def name(code):
         CRASHED: 'crashed',
         SUSPENDED: 'suspended',
         FAILED: 'failed to spawn'}
-    return d[code]
+
+
+def name(code):
+    return _STATE_MAP[code]
+
+
+def valid_states():
+    return _STATE_MAP.keys()
diff --git a/nova/tests/test_compute.py b/nova/tests/test_compute.py
index 44d04a12f..14ff8842b 100644
--- a/nova/tests/test_compute.py
+++ b/nova/tests/test_compute.py
@@ -626,3 +626,24 @@ class ComputeTestCase(test.TestCase):
         db.instance_destroy(c, instance_id)
         db.volume_destroy(c, v_ref['id'])
         db.floating_ip_destroy(c, flo_addr)
+
+    def test_run_kill_vm(self):
+        """Detect when a vm is terminated behind the scenes"""
+        instance_id = self._create_instance()
+
+        self.compute.run_instance(self.context, instance_id)
+
+        instances = db.instance_get_all(context.get_admin_context())
+        LOG.info(_("Running instances: %s"), instances)
+        self.assertEqual(len(instances), 1)
+
+        instance_name = instances[0].name
+        self.compute.driver.test_remove_vm(instance_name)
+
+        # Force the compute manager to do its periodic poll
+        error_list = self.compute.periodic_tasks(context.get_admin_context())
+        self.assertFalse(error_list)
+
+        instances = db.instance_get_all(context.get_admin_context())
+        LOG.info(_("After force-killing instances: %s"), instances)
+        self.assertEqual(len(instances), 0)
diff --git a/nova/utils.py b/nova/utils.py
index 03a6e8095..e4d8a70eb 100644
--- a/nova/utils.py
+++ b/nova/utils.py
@@ -661,3 +661,12 @@ def get_from_path(items, path):
         return results
     else:
         return get_from_path(results, remainder)
+
+
+def check_isinstance(obj, cls):
+    """Checks that obj is of type cls, and lets PyLint infer types"""
+    if isinstance(obj, cls):
+        return obj
+    raise Exception(_("Expected object of type: %s") % (str(cls)))
+    # TODO(justinsb): Can we make this better??
+    return cls()  # Ugly PyLint hack
diff --git a/nova/virt/connection.py b/nova/virt/connection.py
index 13181b730..af7001715 100644
--- a/nova/virt/connection.py
+++ b/nova/virt/connection.py
@@ -23,6 +23,8 @@ import sys
 
 from nova import flags
 from nova import log as logging
+from nova import utils
+from nova.virt import driver
 from nova.virt import fake
 from nova.virt import libvirt_conn
 from nova.virt import xenapi_conn
@@ -72,4 +74,4 @@ def get_connection(read_only=False):
     if conn is None:
         LOG.error(_('Failed to open connection to the hypervisor'))
         sys.exit(1)
-    return conn
+    return utils.check_isinstance(conn, driver.ComputeDriver)
diff --git a/nova/virt/driver.py b/nova/virt/driver.py
new file mode 100644
index 000000000..0e3a4aa3b
--- /dev/null
+++ b/nova/virt/driver.py
@@ -0,0 +1,234 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2011 Justin Santa Barbara
+# 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.
+
+"""
+Driver base-classes:
+
+    (Beginning of) the contract that compute drivers must follow, and shared
+    types that support that contract
+"""
+
+from nova.compute import power_state
+
+
+class InstanceInfo(object):
+    def __init__(self, name, state):
+        self.name = name
+        assert state in power_state.valid_states(), "Bad state: %s" % state
+        self.state = state
+
+
+class ComputeDriver(object):
+    """Base class for compute drivers.
+
+    Lots of documentation is currently on fake.py.
+    """
+
+    def init_host(self, host):
+        """Adopt existing VM's running here"""
+        raise NotImplementedError()
+
+    def get_info(self, instance_name):
+        """Get the current status of an instance, by name (not ID!)
+
+        Returns a dict containing:
+        :state:           the running state, one of the power_state codes
+        :max_mem:         (int) the maximum memory in KBytes allowed
+        :mem:             (int) the memory in KBytes used by the domain
+        :num_cpu:         (int) the number of virtual CPUs for the domain
+        :cpu_time:        (int) the CPU time used in nanoseconds
+        """
+        raise NotImplementedError()
+
+    def list_instances(self):
+        raise NotImplementedError()
+
+    def list_instances_detail(self):
+        """Return a list of InstanceInfo for all registered VMs"""
+        raise NotImplementedError()
+
+    def spawn(self, instance):
+        """Launch a VM for the specified instance"""
+        raise NotImplementedError()
+
+    def destroy(self, instance, cleanup=True):
+        """Shutdown specified VM"""
+        raise NotImplementedError()
+
+    def reboot(self, instance):
+        """Reboot specified VM"""
+        raise NotImplementedError()
+
+    def snapshot_instance(self, context, instance_id, image_id):
+        raise NotImplementedError()
+
+    def get_console_pool_info(self, console_type):
+        """???
+
+        Returns a dict containing:
+        :address:          ???
+        :username:         ???
+        :password:         ???
+        """
+        raise NotImplementedError()
+
+    def get_console_output(self, instance):
+        raise NotImplementedError()
+
+    def get_ajax_console(self, instance):
+        raise NotImplementedError()
+
+    def get_diagnostics(self, instance):
+        """Return data about VM diagnostics"""
+        raise NotImplementedError()
+
+    def get_host_ip_addr(self):
+        raise NotImplementedError()
+
+    def attach_volume(self, context, instance_id, volume_id, mountpoint):
+        raise NotImplementedError()
+
+    def detach_volume(self, context, instance_id, volume_id):
+        raise NotImplementedError()
+
+    def compare_cpu(self, context, cpu_info):
+        raise NotImplementedError()
+
+    def migrate_disk_and_power_off(self, instance, dest):
+        """Transfers the VHD of a running instance to another host, then shuts
+        off the instance copies over the COW disk"""
+        raise NotImplementedError()
+
+    def snapshot(self, instance, image_id):
+        """ Create snapshot from a running VM instance """
+        raise NotImplementedError()
+
+    def finish_resize(self, instance, disk_info):
+        """Completes a resize, turning on the migrated instance"""
+        raise NotImplementedError()
+
+    def revert_resize(self, instance):
+        """Reverts a resize, powering back on the instance"""
+        raise NotImplementedError()
+
+    def pause(self, instance, callback):
+        """Pause VM instance"""
+        raise NotImplementedError()
+
+    def unpause(self, instance, callback):
+        """Unpause paused VM instance"""
+        raise NotImplementedError()
+
+    def suspend(self, instance, callback):
+        """suspend the specified instance"""
+        raise NotImplementedError()
+
+    def resume(self, instance, callback):
+        """resume the specified instance"""
+        raise NotImplementedError()
+
+    def rescue(self, instance, callback):
+        """Rescue the specified instance"""
+        raise NotImplementedError()
+
+    def unrescue(self, instance, callback):
+        """Unrescue the specified instance"""
+        raise NotImplementedError()
+
+    def update_available_resource(self, ctxt, host):
+        """Updates compute manager resource info on ComputeNode table.
+
+        This method is called when nova-compute launches, and
+        whenever admin executes "nova-manage service update_resource".
+
+        :param ctxt: security context
+        :param host: hostname that compute manager is currently running
+
+        """
+        raise NotImplementedError()
+
+    def live_migration(self, ctxt, instance_ref, dest,
+                       post_method, recover_method):
+        """Spawning live_migration operation for distributing high-load.
+
+        :params ctxt: security context
+        :params instance_ref:
+            nova.db.sqlalchemy.models.Instance object
+            instance object that is migrated.
+        :params dest: destination host
+        :params post_method:
+            post operation method.
+            expected nova.compute.manager.post_live_migration.
+        :params recover_method:
+            recovery method when any exception occurs.
+            expected nova.compute.manager.recover_live_migration.
+
+        """
+        raise NotImplementedError()
+
+    def refresh_security_group_rules(self, security_group_id):
+        raise NotImplementedError()
+
+    def refresh_security_group_members(self, security_group_id):
+        raise NotImplementedError()
+
+    def reset_network(self, instance):
+        """reset networking for specified instance"""
+        raise NotImplementedError()
+
+    def ensure_filtering_rules_for_instance(self, instance_ref):
+        """Setting up filtering rules and waiting for its completion.
+
+        To migrate an instance, filtering rules to hypervisors
+        and firewalls are inevitable on destination host.
+        ( Waiting only for filtering rules to hypervisor,
+        since filtering rules to firewall rules can be set faster).
+
+        Concretely, the below method must be called.
+        - setup_basic_filtering (for nova-basic, etc.)
+        - prepare_instance_filter(for nova-instance-instance-xxx, etc.)
+
+        to_xml may have to be called since it defines PROJNET, PROJMASK.
+        but libvirt migrates those value through migrateToURI(),
+        so , no need to be called.
+
+        Don't use thread for this method since migration should
+        not be started when setting-up filtering rules operations
+        are not completed.
+
+        :params instance_ref: nova.db.sqlalchemy.models.Instance object
+
+        """
+        raise NotImplementedError()
+
+    def unfilter_instance(self, instance):
+        """Stop filtering instance"""
+        raise NotImplementedError()
+
+    def set_admin_password(self, context, instance_id, new_pass=None):
+        """Set the root/admin password for an instance on this server."""
+        raise NotImplementedError()
+
+    def inject_file(self, instance, b64_path, b64_contents):
+        """Create a file on the VM instance. The file path and contents
+        should be base64-encoded.
+        """
+        raise NotImplementedError()
+
+    def inject_network_info(self, instance):
+        """inject network info for specified instance"""
+        raise NotImplementedError()
diff --git a/nova/virt/fake.py b/nova/virt/fake.py
index 3a06284a1..5b0fe1877 100644
--- a/nova/virt/fake.py
+++ b/nova/virt/fake.py
@@ -26,7 +26,9 @@ semantics of real hypervisor connections.
 """
 
 from nova import exception
+from nova import utils
 from nova.compute import power_state
+from nova.virt import driver
 
 
 def get_connection(_):
@@ -34,7 +36,14 @@ def get_connection(_):
     return FakeConnection.instance()
 
 
-class FakeConnection(object):
+class FakeInstance(object):
+
+    def __init__(self, name, state):
+        self.name = name
+        self.state = state
+
+
+class FakeConnection(driver.ComputeDriver):
     """
     The interface to this class talks in terms of 'instances' (Amazon EC2 and
     internal Nova terminology), by which we mean 'running virtual machine'
@@ -90,6 +99,17 @@ class FakeConnection(object):
         """
         return self.instances.keys()
 
+    def _map_to_instance_info(self, instance):
+        instance = utils.check_isinstance(instance, FakeInstance)
+        info = driver.InstanceInfo(instance.name, instance.state)
+        return info
+
+    def list_instances_detail(self):
+        info_list = []
+        for instance in self.instances.values():
+            info_list.append(self._map_to_instance_info(instance))
+        return info_list
+
     def spawn(self, instance):
         """
         Create a new instance/VM/domain on the virtualization platform.
@@ -109,9 +129,10 @@ class FakeConnection(object):
         that it was before this call began.
         """
 
-        fake_instance = FakeInstance()
-        self.instances[instance.name] = fake_instance
-        fake_instance._state = power_state.RUNNING
+        name = instance.name
+        state = power_state.RUNNING
+        fake_instance = FakeInstance(name, state)
+        self.instances[name] = fake_instance
 
     def snapshot(self, instance, name):
         """
@@ -270,7 +291,7 @@ class FakeConnection(object):
             raise exception.NotFound(_("Instance %s Not Found")
                                      % instance_name)
         i = self.instances[instance_name]
-        return {'state': i._state,
+        return {'state': i.state,
                 'max_mem': 0,
                 'mem': 0,
                 'num_cpu': 2,
@@ -428,8 +449,6 @@ class FakeConnection(object):
         """This method is supported only by libvirt."""
         raise NotImplementedError('This method is supported only by libvirt.')
 
-
-class FakeInstance(object):
-
-    def __init__(self):
-        self._state = power_state.NOSTATE
+    def test_remove_vm(self, instance_name):
+        """ Removes the named VM, as if it crashed. For testing"""
+        self.instances.pop(instance_name)
diff --git a/nova/virt/hyperv.py b/nova/virt/hyperv.py
index 75fed6d4f..a1ed5ebbf 100644
--- a/nova/virt/hyperv.py
+++ b/nova/virt/hyperv.py
@@ -68,6 +68,7 @@ from nova import flags
 from nova import log as logging
 from nova.auth import manager
 from nova.compute import power_state
+from nova.virt import driver
 from nova.virt import images
 
 wmi = None
@@ -108,8 +109,9 @@ def get_connection(_):
     return HyperVConnection()
 
 
-class HyperVConnection(object):
+class HyperVConnection(driver.ComputeDriver):
     def __init__(self):
+        super(HyperVConnection, self).__init__()
         self._conn = wmi.WMI(moniker='//./root/virtualization')
         self._cim_conn = wmi.WMI(moniker='//./root/cimv2')
 
@@ -124,6 +126,19 @@ class HyperVConnection(object):
                 for v in self._conn.Msvm_ComputerSystem(['ElementName'])]
         return vms
 
+    def list_instances_detail(self):
+        # TODO(justinsb): This is a terrible implementation (1+N)
+        instance_infos = []
+        for instance_name in self.list_instances():
+            info = self.get_info(instance_name)
+
+            state = info['state']
+
+            instance_info = driver.InstanceInfo(instance_name, state)
+            instance_infos.append(instance_info)
+
+        return instance_infos
+
     def spawn(self, instance):
         """ Create a new VM and start it."""
         vm = self._lookup(instance.name)
@@ -345,7 +360,7 @@ class HyperVConnection(object):
         newinst = cl.new()
         #Copy the properties from the original.
         for prop in wmi_obj._properties:
-            newinst.Properties_.Item(prop).Value =\
+            newinst.Properties_.Item(prop).Value = \
                     wmi_obj.Properties_.Item(prop).Value
         return newinst
 
diff --git a/nova/virt/libvirt_conn.py b/nova/virt/libvirt_conn.py
index 67094320e..96f42a8f8 100644
--- a/nova/virt/libvirt_conn.py
+++ b/nova/virt/libvirt_conn.py
@@ -62,6 +62,7 @@ from nova.auth import manager
 from nova.compute import instance_types
 from nova.compute import power_state
 from nova.virt import disk
+from nova.virt import driver
 from nova.virt import images
 
 libvirt = None
@@ -133,8 +134,8 @@ def get_connection(read_only):
 def _late_load_cheetah():
     global Template
     if Template is None:
-        t = __import__('Cheetah.Template', globals(), locals(), ['Template'],
-                       -1)
+        t = __import__('Cheetah.Template', globals(), locals(),
+                       ['Template'], -1)
         Template = t.Template
 
 
@@ -153,9 +154,10 @@ def _get_ip_version(cidr):
         return int(net.version())
 
 
-class LibvirtConnection(object):
+class LibvirtConnection(driver.ComputeDriver):
 
     def __init__(self, read_only):
+        super(LibvirtConnection, self).__init__()
         self.libvirt_uri = self.get_uri()
 
         self.libvirt_xml = open(FLAGS.libvirt_xml_template).read()
@@ -235,6 +237,29 @@ class LibvirtConnection(object):
         return [self._conn.lookupByID(x).name()
                 for x in self._conn.listDomainsID()]
 
+    def _map_to_instance_info(self, domain):
+        """Gets info from a virsh domain object into an InstanceInfo"""
+
+        # domain.info() returns a list of:
+        #    state:       one of the state values (virDomainState)
+        #    maxMemory:   the maximum memory used by the domain
+        #    memory:      the current amount of memory used by the domain
+        #    nbVirtCPU:   the number of virtual CPU
+        #    puTime:      the time used by the domain in nanoseconds
+
+        (state, _max_mem, _mem, _num_cpu, _cpu_time) = domain.info()
+        name = domain.name()
+
+        return driver.InstanceInfo(name, state)
+
+    def list_instances_detail(self):
+        infos = []
+        for domain_id in self._conn.listDomainsID():
+            domain = self._conn.lookupByID(domain_id)
+            info = self._map_to_instance_info(domain)
+            infos.append(info)
+        return infos
+
     def destroy(self, instance, cleanup=True):
         try:
             virt_dom = self._conn.lookupByName(instance['name'])
diff --git a/nova/virt/xenapi/vmops.py b/nova/virt/xenapi/vmops.py
index cfc3a1c22..af39a3def 100644
--- a/nova/virt/xenapi/vmops.py
+++ b/nova/virt/xenapi/vmops.py
@@ -36,6 +36,7 @@ from nova import utils
 
 from nova.auth.manager import AuthManager
 from nova.compute import power_state
+from nova.virt import driver
 from nova.virt.xenapi.network_utils import NetworkHelper
 from nova.virt.xenapi.vm_utils import VMHelper
 from nova.virt.xenapi.vm_utils import ImageType
@@ -57,6 +58,8 @@ class VMOps(object):
 
     def list_instances(self):
         """List VM instances"""
+        # TODO(justinsb): Should we just always use the details method?
+        #  Seems to be the same number of API calls..
         vm_refs = []
         for vm_ref in self._session.get_xenapi().VM.get_all():
             vm_rec = self._session.get_xenapi().VM.get_record(vm_ref)
@@ -64,6 +67,22 @@ class VMOps(object):
                 vm_refs.append(vm_rec["name_label"])
         return vm_refs
 
+    def list_instances_detail(self):
+        """List VM instances, returning InstanceInfo objects"""
+        instance_infos = []
+        for vm_ref in self._session.get_xenapi().VM.get_all():
+            vm_rec = self._session.get_xenapi().VM.get_record(vm_ref)
+            if not vm_rec["is_a_template"] and not vm_rec["is_control_domain"]:
+                name = vm_rec["name_label"]
+
+                # TODO(justinsb): This a roundabout way to map the state
+                openstack_format = VMHelper.compile_info(vm_rec)
+                state = openstack_format['state']
+
+                instance_info = driver.InstanceInfo(name, state)
+                instance_infos.append(instance_info)
+        return instance_infos
+
     def revert_resize(self, instance):
         vm_ref = VMHelper.lookup(self._session, instance.name)
         self._start(instance, vm_ref)
@@ -989,7 +1008,7 @@ class VMOps(object):
         """
         vm_ref = self._get_vm_opaque_ref(instance_or_vm)
         data = self._session.call_xenapi_request('VM.get_xenstore_data',
-                (vm_ref, ))
+                (vm_ref,))
         ret = {}
         if keys is None:
             keys = data.keys()
diff --git a/nova/virt/xenapi_conn.py b/nova/virt/xenapi_conn.py
index 2884687fb..f20fb29d8 100644
--- a/nova/virt/xenapi_conn.py
+++ b/nova/virt/xenapi_conn.py
@@ -69,6 +69,7 @@ from nova import db
 from nova import utils
 from nova import flags
 from nova import log as logging
+from nova.virt import driver
 from nova.virt.xenapi.vmops import VMOps
 from nova.virt.xenapi.volumeops import VolumeOps
 
@@ -141,10 +142,11 @@ def get_connection(_):
     return XenAPIConnection(url, username, password)
 
 
-class XenAPIConnection(object):
+class XenAPIConnection(driver.ComputeDriver):
     """A connection to XenServer or Xen Cloud Platform"""
 
     def __init__(self, url, user, pw):
+        super(XenAPIConnection, self).__init__()
         session = XenAPISession(url, user, pw)
         self._vmops = VMOps(session)
         self._volumeops = VolumeOps(session)
@@ -160,6 +162,9 @@ class XenAPIConnection(object):
         """List VM instances"""
         return self._vmops.list_instances()
 
+    def list_instances_detail(self):
+        return self._vmops.list_instances_detail()
+
     def spawn(self, instance):
         """Create VM instance"""
         self._vmops.spawn(instance)