flexible evacuate host with nova scheduler

Registered by Guangya Liu (Jay Lau) on 2013-10-18

Currently, we can only evacuate vm to a specified host and also we did not make some pre-checking to see if the host is valid or not.

The bp include two requirements:
1) Enable nova scheduler validate target evacuate host if evacuate with a specified host.
2) Enable nova scheduler help select a best target host for evacuate just like live migration without target host.

For item 1), we can leverage the logic from https://blueprints.launchpad.net/nova/+spec/validate-targethost-live-migration.

For item 2), we may need to add an evacuate task just like live migration task and let evacuate task call nova scheduler select_destinations to select best target host for evacuate if evacuate host was not specified.

Blueprint information

Status:
Not started
Approver:
Dan Smith
Priority:
Undefined
Drafter:
None
Direction:
Needs approval
Assignee:
Guangya Liu (Jay Lau)
Definition:
Review
Series goal:
None
Implementation:
Not started
Milestone target:
None

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AFAIK, this has been proposed before in the form of just preserving scheduler hints for any re-schedule operation. IMHO, this should not be an evacuate-specific thing, but a more general attempt to make sure reschedules are consistent with the original. Thoughts? --dansmith
@Dan, I have updated the bp requirement, please help take a look and show your comments. Thanks. --jay-lau-513
[glikson] how #2 is different from https://blueprints.launchpad.net/nova/+spec/find-host-and-evacuate-instance ?
@glikson, my fault, yes, the above blue print has addressed #2. Thanks.

Can you update the blueprint description and dependencies to reflect that another blueprint is addressing part of this? I'd like to see what is clearly in scope for this blueprint and not covered by something else. --russellb

Deferred to icehouse-3 as the blueprint was not approved by the icehouse-2 blueprint approval deadline. --russellb

deferred from icehouse-3 to "next": http://lists.openstack.org/pipermail/openstack-dev/2014-February/026335.html

Removed from next, as next is now reserved for near misses from the last milestone --johnthetubaguy

(?)

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