Add ability to signal and perform online volume size change

Allow Cinder to use external events to signal a volume extension.

1) Nova will then call os-brick to perform the volume extension
   so the host can detect its new size.
2) Compute driver will resize the device in QEMU so instance can detect
   the new disk size without rebooting.

This change:

* Adds the 'volume-extended' external event.
  The event tag needs to be the extended volume id.
* Bumps the latest microversion to 2.51.
* Exposes non-traceback instance action event details for
  non-admins on the microversion. This is needed for the
  non-admin API user that initiated the volume extend
  operation to be able to tell when the nova-compute side
  is complete.

Co-Authored-By: Matt Riedemann <mriedem.os@gmail.com>

Blueprint: nova-support-attached-volume-extend

Change-Id: If10cffd0dc4c9879f6754ce39bee5fae1d04f474

2 files changed, 30 insertions, 6 deletions

diff --git a/api-ref/source/os-instance-actions.inc b/api-ref/source/os-instance-actions.inc
index 99045499c0..c2ac18b5f7 100644
--- a/api-ref/source/os-instance-actions.inc
+++ b/api-ref/source/os-instance-actions.inc
@@ -95,14 +95,20 @@ Response
   - request_id: request_id_body
   - start_time: start_time
   - user_id: user_id
-  - events: instance_action_events
+  - events: instance_action_events_2_50
+  - events: instance_action_events_2_51
   - events.event: event
   - events.start_time: event_start_time
   - events.finish_time: event_finish_time
   - events.result: event_result
   - events.traceback: event_traceback
 
-**Example Show Server Action Details: JSON response**
+**Example Show Server Action Details For Admin (v2.1)**
 
 .. literalinclude:: ../../doc/api_samples/os-instance-actions/instance-action-get-resp.json
    :language: javascript
+
+**Example Show Server Action Details For Non-Admin (v2.51)**
+
+.. literalinclude:: ../../doc/api_samples/os-instance-actions/v2.51/instance-action-get-non-admin-resp.json
+   :language: javascript
diff --git a/api-ref/source/parameters.yaml b/api-ref/source/parameters.yaml
index 49e3ecfeca..150395fbf5 100644
--- a/api-ref/source/parameters.yaml
+++ b/api-ref/source/parameters.yaml
@@ -1518,6 +1518,7 @@ code:
     The HTTP response code for the event. The following codes are currently used:
 
       * 200 - successfully submitted event
+      * 400 - the request is missing required parameter
       * 404 - the instance specified by ``server_uuid`` was not found
       * 422 - no host was found for the server specified by ``server_uuid``,
          so there is no route to this server.
@@ -2001,7 +2002,8 @@ event_finish_time:
 event_name:
   description: |
     The event name. A valid value is ``network-changed``, ``network-vif-plugged``,
-    ``network-vif-unplugged``, or ``network-vif-deleted``.
+    ``network-vif-unplugged``, ``network-vif-deleted``, or ``volume-extended``.
+    The event name ``volume-extended`` is added since microversion ``2.51``.
   in: body
   required: true
   type: string
@@ -2041,7 +2043,11 @@ event_tag:
   type: string
 event_traceback:
   description: |
-    The traceback stack if error occurred in this event.
+    The traceback stack if an error occurred in this event.
+
+    Policy defaults enable only users with the administrative role to see
+    an instance action event traceback. Cloud providers can change these
+    permissions through the ``policy.json`` file.
   in: body
   required: true
   type: string
@@ -3095,9 +3101,9 @@ injectNetworkInfo:
   in: body
   required: true
   type: none
-instance_action_events:
+instance_action_events_2_50:
   description: |
-    The events occurred in this action.
+    The events which occurred in this action.
 
     Policy defaults enable only users with the administrative role to see
     instance action event information. Cloud providers can change these
@@ -3105,6 +3111,18 @@ instance_action_events:
   in: body
   required: false
   type: array
+  max_version: 2.50
+instance_action_events_2_51:
+  description: |
+    The events which occurred in this action.
+
+    Policy defaults enable only users with the administrative role or the owner
+    of the server to see instance action event information. Cloud providers can
+    change these permissions through the ``policy.json`` file.
+  in: body
+  required: true
+  type: array
+  min_version: 2.51
 instance_id_body:
   description: |
     The UUID of the server.