nova allows to live-migrate instance from one availability zone to another

[Timofey Durakov]

Nova allows to live migrate instance from one AZ to another:
Steps to reproduce:
1.boot instance with --availability-zone param
2. live migrate this instance on host located in another AZ, nova live-migration inst1 host2

If user specify host during live-migration scheduler doen't make any checks:
Result: instance migrate successfully, but information in instances table in db doesn't updates
mysql> select hostname, availability_zone from instances where deleted=false;
+----------+-------------------+
| hostname | availability_zone |
+----------+-------------------+
| demo | alice-zone |
+----------+-------------------+

while nova show command show real AZ info:
root@node-7:~# nova show demo
+--------------------------------------+--------------------------------------------------------------------------------------------------+
| Property | Value |
+--------------------------------------+--------------------------------------------------------------------------------------------------+
| OS-EXT-AZ:availability_zone | bob-zone |
| name | demo |
+--------------------------------------+--------------------------------------------------------------------------------------------------+

Nova should forbid such live migration, by adding extra checks, or update info in db table to provide data consistency

[Jason Pan (jason-p-c)]

HI Sylvain,
I have a question about this bug.
In your opinion that cross availability zone live migrate is not allow?

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/254041

[Pawel Koniszewski (pawel-koniszewski)]

Above fix does not really fix this issue, so marking as not in progress.

[stgleb (gstepanov)]

I guess this patch https://review.openstack.org/254041 fixes only updating of AZ. But i didn't found any restrictions for migration instances from one AZ to another.

[Charlotte Han (hanrong)]

related bp:https://blueprints.launchpad.net/nova/+spec/live-migration-with-availability-zone

[Sylvain Bauza (sylvain-bauza)]

Closing an old bug, as it was fixed by http://specs.openstack.org/openstack/nova-specs/specs/newton/implemented/check-destination-on-migrations-newton.html

Now, if you provide a destination, we verify by calling the scheduler for that target unless you provide an explicit "force" flag to the migration call.