Prevent the migration of VM with 'optimize' False in VM metadata

This patch adds the functionality to filter out VMs which have
metadata field 'optimize' set to False. This patch implements the
functionality for basic_consolidation strategy.

Change-Id: Iaf7b63e09534e4a67406e7f092242558b78c0bde
Partially-Implements: BP audit-tag-vm-metadata

watcher/decision_engine/model/element/instance.py

@@ -48,7 +48,7 @@ class Instance(compute_resource.ComputeResource):
         "disk": wfields.IntegerField(),
         "disk_capacity": wfields.NonNegativeIntegerField(),
         "vcpus": wfields.NonNegativeIntegerField(),
-        "metadata": wfields.DictField(),
+        "metadata": wfields.JsonField(),
     }
 
     def accept(self, visitor):

watcher/decision_engine/model/model_root.py

@@ -235,3 +235,10 @@ class ModelRoot(nx.DiGraph, base.Model):
                 model.add_instance(instance)
 
         return model
+
+    @classmethod
+    def is_isomorphic(cls, G1, G2):
+        def node_match(node1, node2):
+            return node1.as_dict() == node2.as_dict()
+        return nx.algorithms.isomorphism.isomorph.is_isomorphic(
+            G1, G2, node_match=node_match)

watcher/decision_engine/strategy/strategies/base.py

@@ -39,6 +39,8 @@ which are dynamically loaded by Watcher at launch time.
 import abc
 import six
 
+from oslo_utils import strutils
+
 from watcher.common import clients
 from watcher.common import context
 from watcher.common import exception
@@ -264,6 +266,22 @@ class BaseStrategy(loadable.Loadable):
     def state_collector(self, s):
         self._cluster_state_collector = s
 
+    def filter_instances_by_audit_tag(self, instances):
+        if not self.config.check_optimize_metadata:
+            return instances
+        instances_to_migrate = []
+        for instance in instances:
+            optimize = True
+            if instance.metadata:
+                try:
+                    optimize = strutils.bool_from_string(
+                        instance.metadata.get('optimize'))
+                except ValueError:
+                    optimize = False
+            if optimize:
+                instances_to_migrate.append(instance)
+        return instances_to_migrate
+
 
 @six.add_metaclass(abc.ABCMeta)
 class DummyBaseStrategy(BaseStrategy):

watcher/decision_engine/strategy/strategies/basic_consolidation.py

@@ -159,7 +159,12 @@ class BasicConsolidation(base.ServerConsolidationBaseStrategy):
                 "datasource",
                 help="Data source to use in order to query the needed metrics",
                 default="ceilometer",
-                choices=["ceilometer", "monasca", "gnocchi"])
+                choices=["ceilometer", "monasca", "gnocchi"]),
+            cfg.BoolOpt(
+                "check_optimize_metadata",
+                help="Check optimize metadata field in instance before "
+                     "migration",
+                default=False),
         ]
 
     @property
@@ -437,9 +442,10 @@ class BasicConsolidation(base.ServerConsolidationBaseStrategy):
     def node_and_instance_score(self, sorted_scores):
         """Get List of VMs from node"""
         node_to_release = sorted_scores[len(sorted_scores) - 1][0]
-        instances_to_migrate = self.compute_model.get_node_instances(
+        instances = self.compute_model.get_node_instances(
             self.compute_model.get_node_by_uuid(node_to_release))
 
+        instances_to_migrate = self.filter_instances_by_audit_tag(instances)
         instance_score = []
         for instance in instances_to_migrate:
             if instance.state == element.InstanceState.ACTIVE.value: