workload evacuate strategy

Registered by suzhengwei

Sometimes if the failure has happened to one compute node, it would be
marked as down. Then we need to evacuate the instances which are running
on this failure compute node.

It needs to do following things:
* add an action to evacuate all the instances of the failure compute node
* add a strategy which will trgger the evacuate action

Now watcher need one strategy, which will trigger the
evacuate action, if one compute node is down.

Blueprint information

Status:
Complete
Approver:
None
Priority:
Undefined
Drafter:
suzhengwei
Direction:
Needs approval
Assignee:
suzhengwei
Definition:
Obsolete
Series goal:
None
Implementation:
Unknown
Milestone target:
None
Completed by
Alexander Chadin

Related branches

Sprints

Whiteboard

Gerrit topic: https://review.openstack.org/#q,topic:bp/workload-evacuate-strategy,n,z

Addressed by: https://review.openstack.org/495168
        workload evacuate strategy

(?)

Work Items

Dependency tree

* Blueprints in grey have been implemented.

This blueprint contains Public information 
Everyone can see this information.