Add Trove cluster capacity autoscaling example

In response to low disk capacity on any cluster nodes an alarm is
raised on the whole cluster and Mistral workflow is triggered to
scale cluster capacity up.

Change-Id: Ie013b44199816fe2b65d0ebfc9b95f7b5324f863
Signed-off-by: Bartosz Zurkowski <b.zurkowski@samsung.com>

etc/vitrage/templates.sample/database_cluster_capacity_autoscaling.yaml

@@ -0,0 +1,82 @@
+metadata:
+  version: 2
+  name: database-cluster-capacity-autoscaling
+  type: standard
+  description: Automatically scales the capacity of Trove database clusters in response to insufficient disk space alerts
+definitions:
+  entities:
+    - entity:
+        category: RESOURCE
+        type: trove.cluster
+        template_id: trove_cluster
+    - entity:
+        category: RESOURCE
+        type: trove.instance
+        template_id: trove_instance
+    - entity:
+        category: ALARM
+        name: trove-instance-low-disk-space
+        template_id: trove_instance_low_disk
+    - entity:
+        category: ALARM
+        name: trove-cluster-low-disk-space
+        template_id: trove_cluster_low_disk
+  relationships:
+    - relationship:
+        source: trove_cluster
+        target: trove_instance
+        relationship_type: contains
+        template_id: trove_cluster_contains_instance
+    - relationship:
+        source: trove_instance_low_disk
+        target: trove_instance
+        relationship_type: on
+        template_id: low_disk_on_trove_instance
+    - relationship:
+        source: trove_cluster_low_disk
+        target: trove_cluster
+        relationship_type: on
+        template_id: low_disk_on_trove_cluster
+scenarios:
+  - scenario:
+      condition: low_disk_on_trove_instance
+      actions:
+        - action:
+            action_type: set_state
+            properties:
+              state: SUBOPTIMAL
+            action_target:
+               target: trove_instance
+  - scenario:
+      condition: low_disk_on_trove_instance and trove_cluster_contains_instance
+      actions:
+        - action:
+            action_type: set_state
+            properties:
+              state: SUBOPTIMAL
+            action_target:
+               target: trove_cluster
+        - action:
+            action_type: raise_alarm
+            properties:
+              alarm_name: trove-cluster-low-disk-space
+              severity: CRITICAL
+            action_target:
+              target: trove_cluster
+  - scenario:
+      condition: low_disk_on_trove_instance and low_disk_on_trove_cluster and trove_cluster_contains_instance
+      actions:
+          - action:
+              action_type: add_causal_relationship
+              action_target:
+                  source: trove_instance_low_disk
+                  target: trove_cluster_low_disk
+  - scenario:
+      condition: low_disk_on_trove_instance and trove_cluster_contains_instance and low_disk_on_trove_cluster
+      actions:
+        - action:
+            action_type: execute_mistral
+            properties:
+              workflow: trove_resize_cluster_volume
+              input:
+                cluster_id: get_attr(trove_cluster,id)