From: Xu Han Peng <xuhanp@cn.ibm.com>
Date: Thu, 9 Apr 2015 05:46:36 +0000 (-0400)
Subject: Not creating HA router when not enough l3 agents
X-Git-Url: https://review.fuel-infra.org/gitweb?a=commitdiff_plain;h=c27310638bff452f54086cf027c442ad2a62e65f;p=openstack-build%2Fneutron-build.git

Not creating HA router when not enough l3 agents

Currently a HA router can be successfully created even when
there is not enough active l3 agent. Current code only checks
existing l3 agents but does not check if the agent is already
down.

This patch fixes this problem by checking only active l3 agents
when getting the number of agents for scheduling HA router.

Closes-Bug: 1420117

Change-Id: I6c1d108db1a7c93b61c0dd0b1ffee319a411b17a
---

diff --git a/neutron/db/l3_hamode_db.py b/neutron/db/l3_hamode_db.py
index 74884d2df..7d52eb1d1 100644
--- a/neutron/db/l3_hamode_db.py
+++ b/neutron/db/l3_hamode_db.py
@@ -262,13 +262,13 @@ class L3_HA_NAT_db_mixin(l3_dvr_db.L3_NAT_with_dvr_db_mixin):
         """
 
         min_agents = cfg.CONF.min_l3_agents_per_router
-        num_agents = len(self.get_l3_agents(context,
+        num_agents = len(self.get_l3_agents(context, active=True,
             filters={'agent_modes': [constants.L3_AGENT_MODE_LEGACY,
                                      constants.L3_AGENT_MODE_DVR_SNAT]}))
         max_agents = cfg.CONF.max_l3_agents_per_router
         if max_agents:
             if max_agents > num_agents:
-                LOG.info(_LI("Number of available agents lower than "
+                LOG.info(_LI("Number of active agents lower than "
                              "max_l3_agents_per_router. L3 agents "
                              "available: %s"), num_agents)
             else:
diff --git a/neutron/tests/unit/db/test_l3_hamode_db.py b/neutron/tests/unit/db/test_l3_hamode_db.py
index e13991aa0..bd8f9e9cd 100644
--- a/neutron/tests/unit/db/test_l3_hamode_db.py
+++ b/neutron/tests/unit/db/test_l3_hamode_db.py
@@ -12,8 +12,10 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+import datetime
 import mock
 from oslo_config import cfg
+from oslo_utils import timeutils
 
 from neutron.api.v2 import attributes
 from neutron.common import constants
@@ -52,22 +54,28 @@ class L3HATestFramework(testlib_api.SqlTestCase):
         cfg.CONF.set_override('allow_overlapping_ips', True)
 
         self.plugin = FakeL3PluginWithAgents()
-        self._register_agents()
+        self.agent1 = self._register_agent('legacy', 'l3host')
+        self.agent2 = self._register_agent('dvr_snat', 'l3host_2')
 
-    def _register_agents(self):
+    def _register_agent(self, agent_mode, host):
         agent_status = {
             'agent_type': constants.AGENT_TYPE_L3,
             'binary': 'neutron-l3-agent',
-            'host': 'l3host',
+            'host': host,
             'topic': 'N/A',
-            'configurations': {'agent_mode': 'legacy'}
+            'configurations': {'agent_mode': agent_mode}
         }
 
         self.plugin.create_or_update_agent(self.admin_ctx, agent_status)
-        agent_status['host'] = 'l3host_2'
-        agent_status['configurations'] = {'agent_mode': 'dvr_snat'}
-        self.plugin.create_or_update_agent(self.admin_ctx, agent_status)
-        self.agent1, self.agent2 = self.plugin.get_agents(self.admin_ctx)
+        return self.plugin.get_agents(
+            self.admin_ctx, filters={'host': [host]})[0]
+
+    def _bring_down_agent(self, agent_id):
+        update = {
+            'agent': {
+                'heartbeat_timestamp':
+                timeutils.utcnow() - datetime.timedelta(hours=1)}}
+        self.plugin.update_agent(self.admin_ctx, agent_id, update)
 
     def _create_router(self, ha=True, tenant_id='tenant1', distributed=None,
                        ctx=None):
@@ -478,6 +486,14 @@ class L3HATestCase(L3HATestFramework):
             self.admin_ctx)
         self.assertEqual(2, num_ha_candidates)
 
+    def test_get_number_of_agents_for_scheduling_not_enough_agents(self):
+        cfg.CONF.set_override('min_l3_agents_per_router', 3)
+        agent_to_bring_down = self._register_agent('legacy', 'l3host_3')
+        self._bring_down_agent(agent_to_bring_down['id'])
+        self.assertRaises(l3_ext_ha_mode.HANotEnoughAvailableAgents,
+                          self.plugin.get_number_of_agents_for_scheduling,
+                          self.admin_ctx)
+
 
 class L3HAModeDbTestCase(L3HATestFramework):
 
diff --git a/neutron/tests/unit/scheduler/test_l3_agent_scheduler.py b/neutron/tests/unit/scheduler/test_l3_agent_scheduler.py
index 09e3f7080..f7ee3d766 100644
--- a/neutron/tests/unit/scheduler/test_l3_agent_scheduler.py
+++ b/neutron/tests/unit/scheduler/test_l3_agent_scheduler.py
@@ -1641,10 +1641,10 @@ class L3HAChanceSchedulerTestCase(L3HATestCaseMixin):
             admin_state_up=True)
         self.assertEqual(2, len(agents))
 
+        r2 = self._create_ha_router()
         self._set_l3_agent_admin_state(self.adminContext,
                                        self.agent_id2, False)
 
-        r2 = self._create_ha_router()
         self.plugin.schedule_router(self.adminContext, r2['id'])
         agents = self.plugin.get_l3_agents_hosting_routers(
             self.adminContext, [r2['id']],