When claims are rejected indicate specific reason

[Christopher Lefelhocz]

In resource_tracker.py upon failure, we raise a generic "ComputeResourcesUnavailable". The logging presents good information as to why there was a failure. We should either provide back data in the ComputeResourcesUnavailble object or raise different exceptions based on what is not available. This may point to a bigger issue of a broken scheduler.

[Christopher Lefelhocz (christopher-lefelhoc)]

This is a low priority development bug at this point.

[Andrew Laski (alaski)]

Right now Claim.test() returns True/False. It tests memory, disk, and cpu separately and could return either a tuple of bools or a dict of True/False values with the keys indicating the resources. Then the resource tracker can update the ComputeResourcesUnavailable exception with appropriate information. It's probably best to just keep the single exception and stuff data into it because there are many possible combinations of which resources are not available.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/61359

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/61359
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=105d99d4f52fa849e80829dad3ed12b116820118
Submitter: Jenkins
Branch: master

commit 105d99d4f52fa849e80829dad3ed12b116820118
Author: jichen <email address hidden>
Date: Wed Dec 11 11:06:26 2013 -0500

    When a claim is rejected, explain why

    Previously, the Claim class offered #test which would return a Boolean
    based on availability of memory, disk, CPU and PCI devices.

    Now these tests are performed from the constructor and if any test
    fails, an exception is thrown. All failure reasons are described in the
    exception message. EG:

      "Insufficient compute resources: Free memory 8192.00 MB <
      requested 16384 MB; Free disk 45.00 GB < requested 50 GB; Free CPUs
      16.00 VCPUs < requested 17 VCPUs."

    Change-Id: I5bf9c81bba747a6c164144e60a92dc6da2f98f4c
    Closes-Bug: #1212768