Add clustered migration sync for shared disks (SYNCING barrier)

Introduce TASK_STATUS_SYNCING and TASK_TYPES_REQUIRING_CLUSTER_SYNC
(DEPLOY_TRANSFER_DISKS, SHUTDOWN_INSTANCE) so multi-instance transfers
with base_transfer_action.clustered=True wait for all peer tasks before
marking COMPLETED and advancing dependents.

- Add clustered boolean on base_transfer_action (DB migration 024)
- Plumb clustered through create_instances_transfer, REST transfers API,
  deployment creation (inherits from parent transfer)
- On task_completed: set SYNCING when barrier applies; when all peers
  are SYNCING, finalize (for deploy: dedupe volumes_info by disk_id,
  leader gets replicate_disk_data=True, followers False)
- ReplicateDisksTask: skip provider replicate_disks for volumes with
  replicate_disk_data=False and merge back in export disk order
- On set_task_error: abort peer tasks stuck in SYNCING for the same type

Volumes schema already allows extra properties; replicate_disk_data is
consumed by replication only (default True preserves behavior).

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 +123,14 @@ connection_info_schema:
   in: body
   type: object
   required: false
+clustered:
+  description: |
+    Present only in API responses (read-only). ``true`` when the transfer
+    includes more than one instance, ``false`` for a single instance. Not
+    stored in the database; derived from ``instances``.
+  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**
 

coriolis/conductor/rpc/client.py

@@ -169,7 +169,8 @@ def create_instances_transfer(self, ctxt,
                                   source_environment, destination_environment,
                                   instances, network_map, storage_mappings,
                                   notes=None, user_scripts=None,
-                                  clone_disks=True, skip_os_morphing=False):
+                                  clone_disks=True, skip_os_morphing=False,
+                                  clustered=None):
         return self._call(
             ctxt, 'create_instances_transfer',
             transfer_scenario=transfer_scenario,
@@ -187,7 +188,8 @@ def create_instances_transfer(self, ctxt,
             source_environment=source_environment,
             user_scripts=user_scripts,
             clone_disks=clone_disks,
-            skip_os_morphing=skip_os_morphing)
+            skip_os_morphing=skip_os_morphing,
+            clustered=clustered)
 
     def get_transfers(self, ctxt, include_tasks_executions=False,
                       include_task_info=False):