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