nova evacuate --on-shared-storage doesn't check actual vm state

[Michał Jastrzębski]

Currently, when we evacuate an instance, evacuation mechanism checks only if nova-compute is down on failed host. If nova compute fails and vm's are still alive, we still can perform evacuation, but 2 separate vms will write to same disk, and that might break data integrity on disk. There should be better host health monitoring, which will give us better hint if we can perform safe evacuation.

[Michał Jastrzębski (inc007)]

This bp is required to fix that: https://review.openstack.org/#/c/137768/

[Markus Zoeller (markus_z) (mzoeller)]

This is an automated cleanup. This bug report has been closed because it
is older than 18 months and there is no open code change to fix this.
After this time it is unlikely that the circumstances which lead to
the observed issue can be reproduced.

If you can reproduce the bug, please:
* reopen the bug report (set to status "New")
* AND add the detailed steps to reproduce the issue (if applicable)
* AND leave a comment "CONFIRMED FOR: <RELEASE_NAME>"
  Only still supported release names are valid (LIBERTY, MITAKA, OCATA, NEWTON).
  Valid example: CONFIRMED FOR: LIBERTY