RetryFilter checks 'node' as well as 'host'

FilterScheduler and RetryFilter use "(host, node)" instead of "host" to
filter candidates. It makes rescheduling on different nodes in the same
host possible.

Fix bug 1081370

Change-Id: Id51b262de7b47b5f9215463eca5ae07a29109c3f

4 files changed, 29 insertions, 21 deletions

diff --git a/nova/scheduler/filter_scheduler.py b/nova/scheduler/filter_scheduler.py
index 7e158765a..95a0df799 100644
--- a/nova/scheduler/filter_scheduler.py
+++ b/nova/scheduler/filter_scheduler.py
@@ -146,24 +146,25 @@ class FilterScheduler(driver.Scheduler):
 
     def _post_select_populate_filter_properties(self, filter_properties,
             host_state):
-        """Add additional information to the filter properties after a host has
+        """Add additional information to the filter properties after a node has
         been selected by the scheduling process.
         """
-        # Add a retry entry for the selected compute host:
-        self._add_retry_host(filter_properties, host_state.host)
+        # Add a retry entry for the selected compute host and node:
+        self._add_retry_host(filter_properties, host_state.host,
+                             host_state.nodename)
 
         self._add_oversubscription_policy(filter_properties, host_state)
 
-    def _add_retry_host(self, filter_properties, host):
-        """Add a retry entry for the selected compute host.  In the event that
+    def _add_retry_host(self, filter_properties, host, node):
+        """Add a retry entry for the selected compute node. In the event that
         the request gets re-scheduled, this entry will signal that the given
-        host has already been tried.
+        node has already been tried.
         """
         retry = filter_properties.get('retry', None)
         if not retry:
             return
         hosts = retry['hosts']
-        hosts.append(host)
+        hosts.append((host, node))
 
     def _add_oversubscription_policy(self, filter_properties, host_state):
         filter_properties['limits'] = host_state.limits
diff --git a/nova/scheduler/filters/retry_filter.py b/nova/scheduler/filters/retry_filter.py
index 6740ec099..108e4d206 100644
--- a/nova/scheduler/filters/retry_filter.py
+++ b/nova/scheduler/filters/retry_filter.py
@@ -20,12 +20,12 @@ LOG = logging.getLogger(__name__)
 
 
 class RetryFilter(filters.BaseHostFilter):
-    """Filter out hosts that have already been attempted for scheduling
+    """Filter out nodes that have already been attempted for scheduling
     purposes
     """
 
     def host_passes(self, host_state, filter_properties):
-        """Skip hosts that have already been attempted"""
+        """Skip nodes that have already been attempted"""
         retry = filter_properties.get('retry', None)
         if not retry:
             # Re-scheduling is disabled
@@ -33,7 +33,7 @@ class RetryFilter(filters.BaseHostFilter):
             return True
 
         hosts = retry.get('hosts', [])
-        host = host_state.host
+        host = (host_state.host, host_state.nodename)
 
         LOG.debug(_("Previously tried hosts: %(hosts)s.  (host=%(host)s)") %
                 locals())
diff --git a/nova/tests/scheduler/test_filter_scheduler.py b/nova/tests/scheduler/test_filter_scheduler.py
index e9412ba60..fcac8b923 100644
--- a/nova/tests/scheduler/test_filter_scheduler.py
+++ b/nova/tests/scheduler/test_filter_scheduler.py
@@ -280,16 +280,17 @@ class FilterSchedulerTestCase(test_scheduler.SchedulerTestCase):
         retry = dict(num_attempts=1, hosts=[])
         filter_properties = dict(retry=retry)
         host = "fakehost"
+        node = "fakenode"
 
         sched = fakes.FakeFilterScheduler()
-        sched._add_retry_host(filter_properties, host)
+        sched._add_retry_host(filter_properties, host, node)
 
         hosts = filter_properties['retry']['hosts']
         self.assertEqual(1, len(hosts))
-        self.assertEqual(host, hosts[0])
+        self.assertEqual((host, node), hosts[0])
 
     def test_post_select_populate(self):
-        """Test addition of certain filter props after a host is selected"""
+        """Test addition of certain filter props after a node is selected"""
         retry = {'hosts': [], 'num_attempts': 1}
         filter_properties = {'retry': retry}
         sched = fakes.FakeFilterScheduler()
@@ -299,12 +300,13 @@ class FilterSchedulerTestCase(test_scheduler.SchedulerTestCase):
         sched._post_select_populate_filter_properties(filter_properties,
                 host_state)
 
-        self.assertEqual('host', filter_properties['retry']['hosts'][0])
+        self.assertEqual(('host', 'node'),
+                         filter_properties['retry']['hosts'][0])
 
         self.assertEqual({'vcpus': 5}, host_state.limits)
 
     def test_prep_resize_post_populates_retry(self):
-        """Prep resize should add a 'host' entry to the retry dict"""
+        """Prep resize should add a ('host', 'node') entry to the retry dict"""
         sched = fakes.FakeFilterScheduler()
 
         image = 'image'
@@ -335,4 +337,5 @@ class FilterSchedulerTestCase(test_scheduler.SchedulerTestCase):
         sched.schedule_prep_resize(self.context, image, request_spec,
                 filter_properties, instance, instance_type, reservations)
 
-        self.assertEqual(['host'], filter_properties['retry']['hosts'])
+        self.assertEqual([('host', 'node')],
+                         filter_properties['retry']['hosts'])
diff --git a/nova/tests/scheduler/test_host_filters.py b/nova/tests/scheduler/test_host_filters.py
index 9a0abb83c..1da29a7a7 100644
--- a/nova/tests/scheduler/test_host_filters.py
+++ b/nova/tests/scheduler/test_host_filters.py
@@ -1269,18 +1269,22 @@ class HostFiltersTestCase(test.TestCase):
         self.assertTrue(filt_cls.host_passes(host, filter_properties))
 
     def test_retry_filter_pass(self):
-        """Host not previously tried"""
+        """Node not previously tried"""
         filt_cls = self.class_map['RetryFilter']()
-        host = fakes.FakeHostState('host1', 'node1', {})
-        retry = dict(num_attempts=1, hosts=['host2', 'host3'])
+        host = fakes.FakeHostState('host1', 'nodeX', {})
+        retry = dict(num_attempts=2,
+                     hosts=[('host1', 'node1'),  # same host, different node
+                            ('host2', 'node2'),  # different host and node
+                            ])
         filter_properties = dict(retry=retry)
         self.assertTrue(filt_cls.host_passes(host, filter_properties))
 
     def test_retry_filter_fail(self):
-        """Host was already tried"""
+        """Node was already tried"""
         filt_cls = self.class_map['RetryFilter']()
         host = fakes.FakeHostState('host1', 'node1', {})
-        retry = dict(num_attempts=1, hosts=['host3', 'host1'])
+        retry = dict(num_attempts=1,
+                     hosts=[('host1', 'node1')])
         filter_properties = dict(retry=retry)
         self.assertFalse(filt_cls.host_passes(host, filter_properties))