Add clustered migration sync for shared disks (SYNCING barrier)

Introduce TASK_STATUS_SYNCING and TASK_TYPES_TO_SYNC (GET_INSTANCE_INFO,
DEPLOY_TRANSFER_DISKS, REPLICATE_DISKS) so multi-instance transfers with
base_transfer_action.clustered=True wait for all peer tasks of the same
type before leaving SYNCING for COMPLETED and advancing dependents.

- clustered is set as len(instances) > 1 on transfer create
- On task_completed: enter SYNCING when the barrier applies, then when
  every peer is SYNCING, run sync hooks (GET_INSTANCE_INFO:
  promote shareable on export disks, DEPLOY_TRANSFER_DISKS:
  shared-disk volumes_info, REPLICATE_DISKS: sync change_id)
- ReplicateDisksTask: skip provider replicate for replicate_disk_data=False
- On task error: abort peers stuck in SYNCING for the same task type

Author: fabi200123

coriolis/api-refs/api_samples/transfer/openstack-transfer-create-resp.json

@@ -49,6 +49,7 @@
       }
     },
     "executions": [],
-    "scenario": "replica"
+    "scenario": "replica",
+    "clustered": false
   }
 }

coriolis/api-refs/api_samples/transfer/openstack-transfer-get-resp.json

@@ -42,6 +42,7 @@
     "origin_minion_pool_id": null,
     "destination_minion_pool_id": null,
     "instance_osmorphing_minion_pool_mappings": {},
+    "clustered": false,
     "executions": [
       {
         "created_at": "2019-07-11T10:06:47.000000",

coriolis/api-refs/api_samples/transfer/transfer-list-resp.json

@@ -74,7 +74,8 @@
         "instances": {}
       },
       "id": "0460aa4d-6b16-4c98-bd56-27ee186e4a22",
-      "scenario": "replica"
+      "scenario": "replica",
+      "clustered": false
     }
   ]
 }

coriolis/api-refs/api_samples/transfer/transfer-update-resp.json

@@ -133,7 +133,8 @@
           "ubuntu-xenial": "echo 'anything you need'"
         }
       },
-      "scenario": "replica"
+      "scenario": "replica",
+      "clustered": false
     }
   }
 }

coriolis/api-refs/source/parameters.yaml

@@ -123,6 +123,15 @@ connection_info_schema:
   in: body
   type: object
   required: false
+clustered:
+  description: |
+    Present on transfer responses. ``true`` when more than one instance is
+    listed (multi-instance scheduling: sync barriers and shared-disk
+    coordination). Set by the server at creation from ``instances``; not
+    accepted on create.
+  in: body
+  type: boolean
+  required: false
 deployment_cancel:
   description: |
     Object containing information about the type of deployment cancellation.

coriolis/api-refs/source/transfer.inc

@@ -51,6 +51,7 @@ Response
   - instance_osmorphing_minion_pool_mappings : instance_osmorphing_minion_pool_mappings
   - user_scripts : user_scripts
   - scenario: scenario_type
+  - clustered : clustered
 
 **Example of Transfer List Response**
 
@@ -111,6 +112,7 @@ Response
   - instance_osmorphing_minion_pool_mappings : instance_osmorphing_minion_pool_mappings
   - user_scripts : user_scripts
   - scenario: scenario_type
+  - clustered : clustered
 
 **Example of Transfer Show Response**
 
@@ -183,6 +185,7 @@ Response
   - instance_osmorphing_minion_pool_mappings : instance_osmorphing_minion_pool_mappings
   - user_scripts : user_scripts
   - scenario: scenario_type
+  - clustered : clustered
 
 **Example of Transfer Create Response**