Refactored the compute model and its elements

In this changeset, I refactored the whole Watcher codebase to
adopt a naming convention about the various elements of the
Compute model so that it reflects the same naming convention
adopted by Nova.

Change-Id: I28adba5e1f27175f025330417b072686134d5f51
Partially-Implements: blueprint cluster-model-objects-wrapper

watcher/applier/actions/migration.py

@@ -44,12 +44,12 @@ class Migrate(base.BaseAction):
         schema = Schema({
          'resource_id': str,  # should be a UUID
          'migration_type': str,  # choices -> "live", "cold"
-         'dst_hypervisor': str,
-         'src_hypervisor': str,
+         'destination_node': str,
+         'source_node': str,
         })
 
     The `resource_id` is the UUID of the server to migrate.
-    The `src_hypervisor` and `dst_hypervisor` parameters are respectively the
+    The `source_node` and `destination_node` parameters are respectively the
     source and the destination compute hostname (list of available compute
     hosts is returned by this command: ``nova service-list --binary
     nova-compute``).
@@ -59,8 +59,8 @@ class Migrate(base.BaseAction):
     MIGRATION_TYPE = 'migration_type'
     LIVE_MIGRATION = 'live'
     COLD_MIGRATION = 'cold'
-    DST_HYPERVISOR = 'dst_hypervisor'
-    SRC_HYPERVISOR = 'src_hypervisor'
+    DESTINATION_NODE = 'destination_node'
+    SOURCE_NODE = 'source_node'
 
     def check_resource_id(self, value):
         if (value is not None and
@@ -73,14 +73,14 @@ class Migrate(base.BaseAction):
     def schema(self):
         return voluptuous.Schema({
             voluptuous.Required(self.RESOURCE_ID): self.check_resource_id,
-            voluptuous.Required(self.MIGRATION_TYPE,
-                                default=self.LIVE_MIGRATION):
-                                    voluptuous.Any(*[self.LIVE_MIGRATION,
-                                                     self.COLD_MIGRATION]),
-            voluptuous.Required(self.DST_HYPERVISOR):
+            voluptuous.Required(
+                self.MIGRATION_TYPE, default=self.LIVE_MIGRATION):
+                    voluptuous.Any(
+                        *[self.LIVE_MIGRATION, self.COLD_MIGRATION]),
+            voluptuous.Required(self.DESTINATION_NODE):
                 voluptuous.All(voluptuous.Any(*six.string_types),
                                voluptuous.Length(min=1)),
-            voluptuous.Required(self.SRC_HYPERVISOR):
+            voluptuous.Required(self.SOURCE_NODE):
                 voluptuous.All(voluptuous.Any(*six.string_types),
                                voluptuous.Length(min=1)),
         })
@@ -94,12 +94,12 @@ class Migrate(base.BaseAction):
         return self.input_parameters.get(self.MIGRATION_TYPE)
 
     @property
-    def dst_hypervisor(self):
-        return self.input_parameters.get(self.DST_HYPERVISOR)
+    def destination_node(self):
+        return self.input_parameters.get(self.DESTINATION_NODE)
 
     @property
-    def src_hypervisor(self):
-        return self.input_parameters.get(self.SRC_HYPERVISOR)
+    def source_node(self):
+        return self.input_parameters.get(self.SOURCE_NODE)
 
     def _live_migrate_instance(self, nova, destination):
         result = None
@@ -159,14 +159,14 @@ class Migrate(base.BaseAction):
             raise exception.InstanceNotFound(name=self.instance_uuid)
 
     def execute(self):
-        return self.migrate(destination=self.dst_hypervisor)
+        return self.migrate(destination=self.destination_node)
 
     def revert(self):
-        return self.migrate(destination=self.src_hypervisor)
+        return self.migrate(destination=self.source_node)
 
     def precondition(self):
         # todo(jed) check if the instance exist/ check if the instance is on
-        # the src_hypervisor
+        # the source_node
         pass
 
     def postcondition(self):