vmware: Delete duplicate DRS rules

Cross-cluster vMotion creates DRS rules in the target cluster, if the VM
was part of them in the source cluster. This can create duplicate DRS
rules (by name), as it seems VMware looks at the UUID of the rule not
the name.

Since multiple rules for the same VM cannot be enabled at the same time
and `cluster_util.get_rule()` only returns the first matching rule, Nova
might update the wrong rule and the anti-affinity might not actually
work.

To fix this, we get all the rules with the same name during
`_update_rule()` to check for duplicates. We keep the first rule we find
and delete all others. If the rule is disabled, Nova will enable it
already. Since Nova always updates its rule with the VMs that should be
in there, any VM being in a deleted duplicate rule is handled, too.

Change-Id: Ie5958a1645e8133f303e386353526ec83e646882

nova/virt/vmwareapi/vmops.py

@@ -4332,8 +4332,23 @@ def _sync_sync_server_group(context, sg_uuid):
             LOG.debug('Sync for server-group %s done', sg_uuid)
 
         def _update_rule(rule_name, expected_members, sg):
-            rule = cluster_util.get_rule(
-                self._session, self._cluster, rule_name)
+            # we need to get by "prefix", to get all rules matching our name,
+            # as there can be duplication happening with automatically
+            # vSphere-created rules during vMotion
+            rules = [r for r in cluster_util.get_rules_by_prefix(
+                        self._session, self._cluster, rule_name)
+                     if r.name == rule_name]
+
+            rule = rules[0] if rules else None
+
+            # if we have duplicates (with the same name), delete them
+            for dupl_rule in rules[1:]:
+                LOG.debug('Deleting DRS rule %s with key %s as duplicate',
+                          dupl_rule.name, dupl_rule.key)
+                cluster_util.delete_rule(
+                    self._session, self._cluster, dupl_rule)
+                LOG.info('Deleted rule %s with key %s as duplicate',
+                         dupl_rule.name, dupl_rule.key)
 
             if not rule:
                 if len(expected_members) < 2 or sg.policy == 'soft-affinity':