nova doesn't always find images in glance in HA mode

[Steven Dake]

With 3 control nodes, glance has the following behavior:

Script started on Sat Oct 10 23:50:49 2015
[?1034hbash-3.2$ glance image-download --file abc 22e61335-73eb-410a-892c-5490c8abadb0
'NoneType' object has no attribute 'close'
bash-3.2$ glance image-download --file abc 22e61335-73eb-410a-892c-5490c8abadb0
'NoneType' object has no attribute 'close'
bash-3.2$ glance image-download --file abc 22e61335-73eb-410a-892c-5490c8abadb0
bash-3.2$ glance image-download --file abc 22e61335-73eb-410a-892c-5490c8abadb0
'NoneType' object has no attribute 'close'
bash-3.2$ glance image-download --file abc 22e61335-73eb-410a-892c-5490c8abadb0
'NoneType' object has no attribute 'close'
bash-3.2$ glance image-download --file abc 22e61335-73eb-410a-892c-5490c8abadb0

every third one works. Nova returns an error on access to glance api calls at same ratio.

Sam has indicated this is normal behavior for a storage backend of file. Sam suggested a solution which locks down the access to one glance api service (I believe) in this change:

https://review.openstack.org/#/c/233429/

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/233429
Committed: https://git.openstack.org/cgit/openstack/kolla/commit/?id=0cefd644502c7a8851403cbb2e60dd79c906d475
Submitter: Jenkins
Branch: master

commit 0cefd644502c7a8851403cbb2e60dd79c906d475
Author: Sam Yaple <email address hidden>
Date: Sun Oct 11 07:22:37 2015 +0000

    Glance round robin for default file backend

    Closes-Bug: #1504902
    Change-Id: Id4cced68ef078adb3db19c67f62d96275ab2329f

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/liberty
Review: https://review.openstack.org/233593

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/233593
Committed: https://git.openstack.org/cgit/openstack/kolla/commit/?id=4b0c088ad105151578e6239b544d8e52dd4f1800
Submitter: Jenkins
Branch: stable/liberty

commit 4b0c088ad105151578e6239b544d8e52dd4f1800
Author: Sam Yaple <email address hidden>
Date: Sun Oct 11 07:22:37 2015 +0000

    Glance round robin for default file backend

    Closes-Bug: #1504902
    Change-Id: Id4cced68ef078adb3db19c67f62d96275ab2329f
    (cherry picked from commit 0cefd644502c7a8851403cbb2e60dd79c906d475)