Adds the os-hosts API extension for interacting with hosts while performing maintenance. This differs from the previous merge prop as it uses a RESTful design instead of GET-based actions.

This supersedes the previous merge prop (https://code.launchpad.net/~ed-leafe/nova/maintmode/+merge/66303). The code has been both simplified and cleaned up a great deal, so there is no real need for the previous interim code.

15 files changed, 344 insertions, 7 deletions

diff --git a/nova/api/openstack/contrib/hosts.py b/nova/api/openstack/contrib/hosts.py
new file mode 100644
index 000000000..55e57e1a4
--- /dev/null
+++ b/nova/api/openstack/contrib/hosts.py
@@ -0,0 +1,114 @@
+# 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.
+
+"""The hosts admin extension."""
+
+import webob.exc
+
+from nova import compute
+from nova import exception
+from nova import flags
+from nova import log as logging
+from nova.api.openstack import common
+from nova.api.openstack import extensions
+from nova.api.openstack import faults
+from nova.scheduler import api as scheduler_api
+
+
+LOG = logging.getLogger("nova.api.hosts")
+FLAGS = flags.FLAGS
+
+
+def _list_hosts(req, service=None):
+    """Returns a summary list of hosts, optionally filtering
+    by service type.
+    """
+    context = req.environ['nova.context']
+    hosts = scheduler_api.get_host_list(context)
+    if service:
+        hosts = [host for host in hosts
+                if host["service"] == service]
+    return hosts
+
+
+def check_host(fn):
+    """Makes sure that the host exists."""
+    def wrapped(self, req, id, service=None, *args, **kwargs):
+        listed_hosts = _list_hosts(req, service)
+        hosts = [h["host_name"] for h in listed_hosts]
+        if id in hosts:
+            return fn(self, req, id, *args, **kwargs)
+        else:
+            raise exception.HostNotFound(host=id)
+    return wrapped
+
+
+class HostController(object):
+    """The Hosts API controller for the OpenStack API."""
+    def __init__(self):
+        self.compute_api = compute.API()
+        super(HostController, self).__init__()
+
+    def index(self, req):
+        return {'hosts': _list_hosts(req)}
+
+    @check_host
+    def update(self, req, id, body):
+        for raw_key, raw_val in body.iteritems():
+            key = raw_key.lower().strip()
+            val = raw_val.lower().strip()
+            # NOTE: (dabo) Right now only 'status' can be set, but other
+            # actions may follow.
+            if key == "status":
+                if val[:6] in ("enable", "disabl"):
+                    return self._set_enabled_status(req, id,
+                            enabled=(val.startswith("enable")))
+                else:
+                    explanation = _("Invalid status: '%s'") % raw_val
+                    raise webob.exc.HTTPBadRequest(explanation=explanation)
+            else:
+                explanation = _("Invalid update setting: '%s'") % raw_key
+                raise webob.exc.HTTPBadRequest(explanation=explanation)
+
+    def _set_enabled_status(self, req, host, enabled):
+        """Sets the specified host's ability to accept new instances."""
+        context = req.environ['nova.context']
+        state = "enabled" if enabled else "disabled"
+        LOG.audit(_("Setting host %(host)s to %(state)s.") % locals())
+        result = self.compute_api.set_host_enabled(context, host=host,
+                enabled=enabled)
+        return {"host": host, "status": result}
+
+
+class Hosts(extensions.ExtensionDescriptor):
+    def get_name(self):
+        return "Hosts"
+
+    def get_alias(self):
+        return "os-hosts"
+
+    def get_description(self):
+        return "Host administration"
+
+    def get_namespace(self):
+        return "http://docs.openstack.org/ext/hosts/api/v1.1"
+
+    def get_updated(self):
+        return "2011-06-29T00:00:00+00:00"
+
+    def get_resources(self):
+        resources = [extensions.ResourceExtension('os-hosts', HostController(),
+                collection_actions={'update': 'PUT'}, member_actions={})]
+        return resources
diff --git a/nova/compute/api.py b/nova/compute/api.py
index 28459dc75..b0eedcd64 100644
--- a/nova/compute/api.py
+++ b/nova/compute/api.py
@@ -912,6 +912,11 @@ class API(base.Base):
         """Unpause the given instance."""
         self._cast_compute_message('unpause_instance', context, instance_id)
 
+    def set_host_enabled(self, context, host, enabled):
+        """Sets the specified host's ability to accept new instances."""
+        return self._call_compute_message("set_host_enabled", context,
+                instance_id=None, host=host, params={"enabled": enabled})
+
     @scheduler_api.reroute_compute("diagnostics")
     def get_diagnostics(self, context, instance_id):
         """Retrieve diagnostics for the given instance."""
diff --git a/nova/compute/manager.py b/nova/compute/manager.py
index bbbddde0a..91a604934 100644
--- a/nova/compute/manager.py
+++ b/nova/compute/manager.py
@@ -875,6 +875,12 @@ class ComputeManager(manager.SchedulerDependentManager):
                                                        result))
 
     @exception.wrap_exception
+    def set_host_enabled(self, context, instance_id=None, host=None,
+            enabled=None):
+        """Sets the specified host's ability to accept new instances."""
+        return self.driver.set_host_enabled(host, enabled)
+
+    @exception.wrap_exception
     def get_diagnostics(self, context, instance_id):
         """Retrieve diagnostics for an instance on this host."""
         instance_ref = self.db.instance_get(context, instance_id)
diff --git a/nova/scheduler/api.py b/nova/scheduler/api.py
index 0f4fc48c8..137b671c0 100644
--- a/nova/scheduler/api.py
+++ b/nova/scheduler/api.py
@@ -51,6 +51,11 @@ def _call_scheduler(method, context, params=None):
     return rpc.call(context, queue, kwargs)
 
 
+def get_host_list(context):
+    """Return a list of hosts associated with this zone."""
+    return _call_scheduler('get_host_list', context)
+
+
 def get_zone_list(context):
     """Return a list of zones assoicated with this zone."""
     items = _call_scheduler('get_zone_list', context)
diff --git a/nova/scheduler/manager.py b/nova/scheduler/manager.py
index 6cb75aa8d..749d66cad 100644
--- a/nova/scheduler/manager.py
+++ b/nova/scheduler/manager.py
@@ -56,6 +56,10 @@ class SchedulerManager(manager.Manager):
         """Poll child zones periodically to get status."""
         self.zone_manager.ping(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_zone_list(self, context=None):
         """Get a list of zones from the ZoneManager."""
         return self.zone_manager.get_zone_list()
diff --git a/nova/scheduler/zone_manager.py b/nova/scheduler/zone_manager.py
index ba7403c15..6093443a9 100644
--- a/nova/scheduler/zone_manager.py
+++ b/nova/scheduler/zone_manager.py
@@ -115,6 +115,18 @@ class ZoneManager(object):
         """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 get_zone_capabilities(self, context):
         """Roll up all the individual host info to generic 'service'
            capabilities. Each capability is aggregated into
@@ -127,13 +139,15 @@ class ZoneManager(object):
         combined = {}  # { <service>_<cap> : (min, max), ... }
         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
                 for cap, value in service_dict.iteritems():
                     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)
-
         return combined
 
     def _refresh_from_db(self, context):
diff --git a/nova/tests/test_hosts.py b/nova/tests/test_hosts.py
new file mode 100644
index 000000000..548f81f8b
--- /dev/null
+++ b/nova/tests/test_hosts.py
@@ -0,0 +1,102 @@
+# 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.
+
+import stubout
+import webob.exc
+
+from nova import context
+from nova import exception
+from nova import flags
+from nova import log as logging
+from nova import test
+from nova.api.openstack.contrib import hosts as os_hosts
+from nova.scheduler import api as scheduler_api
+
+
+FLAGS = flags.FLAGS
+LOG = logging.getLogger('nova.tests.hosts')
+# Simulate the hosts returned by the zone manager.
+HOST_LIST = [
+        {"host_name": "host_c1", "service": "compute"},
+        {"host_name": "host_c2", "service": "compute"},
+        {"host_name": "host_v1", "service": "volume"},
+        {"host_name": "host_v2", "service": "volume"}]
+
+
+def stub_get_host_list(req):
+    return HOST_LIST
+
+
+def stub_set_host_enabled(context, host, enabled):
+    # We'll simulate success and failure by assuming
+    # that 'host_c1' always succeeds, and 'host_c2'
+    # always fails
+    fail = (host == "host_c2")
+    status = "enabled" if (enabled ^ fail) else "disabled"
+    return status
+
+
+class FakeRequest(object):
+    environ = {"nova.context": context.get_admin_context()}
+
+
+class HostTestCase(test.TestCase):
+    """Test Case for hosts."""
+
+    def setUp(self):
+        super(HostTestCase, self).setUp()
+        self.controller = os_hosts.HostController()
+        self.req = FakeRequest()
+        self.stubs.Set(scheduler_api, 'get_host_list', stub_get_host_list)
+        self.stubs.Set(self.controller.compute_api, 'set_host_enabled',
+                stub_set_host_enabled)
+
+    def test_list_hosts(self):
+        """Verify that the compute hosts are returned."""
+        hosts = os_hosts._list_hosts(self.req)
+        self.assertEqual(hosts, HOST_LIST)
+
+        compute_hosts = os_hosts._list_hosts(self.req, "compute")
+        expected = [host for host in HOST_LIST
+                if host["service"] == "compute"]
+        self.assertEqual(compute_hosts, expected)
+
+    def test_disable_host(self):
+        dis_body = {"status": "disable"}
+        result_c1 = self.controller.update(self.req, "host_c1", body=dis_body)
+        self.assertEqual(result_c1["status"], "disabled")
+        result_c2 = self.controller.update(self.req, "host_c2", body=dis_body)
+        self.assertEqual(result_c2["status"], "enabled")
+
+    def test_enable_host(self):
+        en_body = {"status": "enable"}
+        result_c1 = self.controller.update(self.req, "host_c1", body=en_body)
+        self.assertEqual(result_c1["status"], "enabled")
+        result_c2 = self.controller.update(self.req, "host_c2", body=en_body)
+        self.assertEqual(result_c2["status"], "disabled")
+
+    def test_bad_status_value(self):
+        bad_body = {"status": "bad"}
+        self.assertRaises(webob.exc.HTTPBadRequest, self.controller.update,
+                self.req, "host_c1", body=bad_body)
+
+    def test_bad_update_key(self):
+        bad_body = {"crazy": "bad"}
+        self.assertRaises(webob.exc.HTTPBadRequest, self.controller.update,
+                self.req, "host_c1", body=bad_body)
+
+    def test_bad_host(self):
+        self.assertRaises(exception.HostNotFound, self.controller.update,
+                self.req, "bogus_host_name", body={"status": "disable"})
diff --git a/nova/virt/driver.py b/nova/virt/driver.py
index 1c9797973..3c4a073bf 100644
--- a/nova/virt/driver.py
+++ b/nova/virt/driver.py
@@ -249,3 +249,7 @@ class ComputeDriver(object):
     def poll_rescued_instances(self, timeout):
         """Poll for rescued instances"""
         raise NotImplementedError()
+
+    def set_host_enabled(self, host, enabled):
+        """Sets the specified host's ability to accept new instances."""
+        raise NotImplementedError()
diff --git a/nova/virt/fake.py b/nova/virt/fake.py
index 5fe9d674f..ea0a59f21 100644
--- a/nova/virt/fake.py
+++ b/nova/virt/fake.py
@@ -514,3 +514,7 @@ class FakeConnection(driver.ComputeDriver):
     def get_host_stats(self, refresh=False):
         """Return fake Host Status of ram, disk, network."""
         return self.host_status
+
+    def set_host_enabled(self, host, enabled):
+        """Sets the specified host's ability to accept new instances."""
+        pass
diff --git a/nova/virt/hyperv.py b/nova/virt/hyperv.py
index f6783f3aa..5c1dc772d 100644
--- a/nova/virt/hyperv.py
+++ b/nova/virt/hyperv.py
@@ -499,3 +499,7 @@ class HyperVConnection(driver.ComputeDriver):
     def get_host_stats(self, refresh=False):
         """See xenapi_conn.py implementation."""
         pass
+
+    def set_host_enabled(self, host, enabled):
+        """Sets the specified host's ability to accept new instances."""
+        pass
diff --git a/nova/virt/libvirt/connection.py b/nova/virt/libvirt/connection.py
index 233d14203..e912c2bec 100644
--- a/nova/virt/libvirt/connection.py
+++ b/nova/virt/libvirt/connection.py
@@ -1591,3 +1591,7 @@ class LibvirtConnection(driver.ComputeDriver):
     def get_host_stats(self, refresh=False):
         """See xenapi_conn.py implementation."""
         pass
+
+    def set_host_enabled(self, host, enabled):
+        """Sets the specified host's ability to accept new instances."""
+        pass
diff --git a/nova/virt/vmwareapi_conn.py b/nova/virt/vmwareapi_conn.py
index 3c6345ec8..d80e14931 100644
--- a/nova/virt/vmwareapi_conn.py
+++ b/nova/virt/vmwareapi_conn.py
@@ -190,6 +190,10 @@ class VMWareESXConnection(driver.ComputeDriver):
         """This method is supported only by libvirt."""

         return

 

+    def set_host_enabled(self, host, enabled):

+        """Sets the specified host's ability to accept new instances."""

+        pass

+

 

 class VMWareAPISession(object):

     """

diff --git a/nova/virt/xenapi/vmops.py b/nova/virt/xenapi/vmops.py
index b116c8467..cb96930c1 100644
--- a/nova/virt/xenapi/vmops.py
+++ b/nova/virt/xenapi/vmops.py
@@ -24,6 +24,7 @@ import json
 import M2Crypto
 import os
 import pickle
+import random
 import subprocess
 import time
 import uuid
@@ -932,6 +933,31 @@ class VMOps(object):
         # TODO: implement this!
         return 'http://fakeajaxconsole/fake_url'
 
+    def set_host_enabled(self, host, enabled):
+        """Sets the specified host's ability to accept new instances."""
+        args = {"enabled": json.dumps(enabled)}
+        json_resp = self._call_xenhost("set_host_enabled", args)
+        resp = json.loads(json_resp)
+        return resp["status"]
+
+    def _call_xenhost(self, method, arg_dict):
+        """There will be several methods that will need this general
+        handling for interacting with the xenhost plugin, so this abstracts
+        out that behavior.
+        """
+        # Create a task ID as something that won't match any instance ID
+        task_id = random.randint(-80000, -70000)
+        try:
+            task = self._session.async_call_plugin("xenhost", method,
+                    args=arg_dict)
+                    #args={"params": arg_dict})
+            ret = self._session.wait_for_task(task, task_id)
+        except self.XenAPI.Failure as e:
+            ret = None
+            LOG.error(_("The call to %(method)s returned an error: %(e)s.")
+                    % locals())
+        return ret
+
     def inject_network_info(self, instance, network_info, vm_ref=None):
         """
         Generate the network info and make calls to place it into the
diff --git a/nova/virt/xenapi_conn.py b/nova/virt/xenapi_conn.py
index cd4dc1b60..ec8c44c1c 100644
--- a/nova/virt/xenapi_conn.py
+++ b/nova/virt/xenapi_conn.py
@@ -336,6 +336,10 @@ class XenAPIConnection(driver.ComputeDriver):
            True, run the update first."""
         return self.HostState.get_host_stats(refresh=refresh)
 
+    def set_host_enabled(self, host, enabled):
+        """Sets the specified host's ability to accept new instances."""
+        return self._vmops.set_host_enabled(host, enabled)
+
 
 class XenAPISession(object):
     """The session to invoke XenAPI SDK calls"""
diff --git a/plugins/xenserver/xenapi/etc/xapi.d/plugins/xenhost b/plugins/xenserver/xenapi/etc/xapi.d/plugins/xenhost
index a8428e841..292bbce12 100644
--- a/plugins/xenserver/xenapi/etc/xapi.d/plugins/xenhost
+++ b/plugins/xenserver/xenapi/etc/xapi.d/plugins/xenhost
@@ -33,9 +33,10 @@ import tempfile
 import time
 
 import XenAPIPlugin
+import pluginlib_nova as pluginlib
 
-from pluginlib_nova import *
-configure_logging("xenhost")
+
+pluginlib.configure_logging("xenhost")
 
 host_data_pattern = re.compile(r"\s*(\S+) \([^\)]+\) *: ?(.*)")
 
@@ -65,14 +66,49 @@ def _run_command(cmd):
     return proc.stdout.read()
 
 
+def _get_host_uuid():
+    cmd = "xe host-list | grep uuid"
+    resp = _run_command(cmd)
+    return resp.split(":")[-1].strip()
+
+
+@jsonify
+def set_host_enabled(self, arg_dict):
+    """Sets this host's ability to accept new instances.
+    It will otherwise continue to operate normally.
+    """
+    enabled = arg_dict.get("enabled")
+    if enabled is None:
+        raise pluginlib.PluginError(
+                _("Missing 'enabled' argument to set_host_enabled"))
+    if enabled == "true":
+        result = _run_command("xe host-enable")
+    elif enabled == "false":
+        result = _run_command("xe host-disable")
+    else:
+        raise pluginlib.PluginError(_("Illegal enabled status: %s") % enabled)
+    # Should be empty string
+    if result:
+        raise pluginlib.PluginError(result)
+    # Return the current enabled status
+    host_uuid = _get_host_uuid()
+    cmd = "xe host-param-list uuid=%s | grep enabled" % host_uuid
+    resp = _run_command(cmd)
+    # Response should be in the format: "enabled ( RO): true"
+    host_enabled = resp.strip().split()[-1]
+    if host_enabled == "true":
+        status = "enabled"
+    else:
+        status = "disabled"
+    return {"status": status}
+
+
 @jsonify
 def host_data(self, arg_dict):
     """Runs the commands on the xenstore host to return the current status
     information.
     """
-    cmd = "xe host-list | grep uuid"
-    resp = _run_command(cmd)
-    host_uuid = resp.split(":")[-1].strip()
+    host_uuid = _get_host_uuid()
     cmd = "xe host-param-list uuid=%s" % host_uuid
     resp = _run_command(cmd)
     parsed_data = parse_response(resp)
@@ -180,4 +216,5 @@ def cleanup(dct):
 
 if __name__ == "__main__":
     XenAPIPlugin.dispatch(
-        {"host_data": host_data})
+            {"host_data": host_data,
+            "set_host_enabled": set_host_enabled})