Improve Scheduler Logging

Registered by Chris Friesen on 2016-04-15

The nova scheduler includes a number of very complicated filters with
non-obvious failure modes (the NUMATopologyFilter in particular comes to mind).
It is possible to have a situation where a given instances fails to schedule,
and it is not immediately apparent as to what exactly caused the failure.
Accordingly, it is proposed that we allow for optional detailed messages about
precisely *why* a scheduler filter is failing.

Blueprint information

Status:
Started
Approver:
John Garbutt
Priority:
Medium
Drafter:
Chris Friesen
Direction:
Needs approval
Assignee:
Chris Friesen
Definition:
Pending Approval
Series goal:
None
Implementation:
Beta Available
Milestone target:
None
Started by
Matt Riedemann on 2016-06-23

Related branches

Sprints

Whiteboard

Gerrit topic: https://review.openstack.org/#q,topic:bp/improve-sched-logging,n,z

Addressed by: https://review.openstack.org/331306
    Allow logging detailed info only on sched failure

There are still open questions for this and we're past non-priority feature freeze for Newton so this is going to be deferred to Ocata. -- mriedem 20160705

Gerrit topic: https://review.openstack.org/#q,topic:bug/1787298,n,z

Addressed by: https://review.openstack.org/600269
    This commit adds __str__ method to objects InstanceNUMACell and NUMACell. These will generate more readable representations of the objects for use in logs.

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Work Items

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