overcloud deploy fails if any container image pull fails

[Steve Baker]

Deployment failure rates will be high when container images are pulled over the internet. Even when using the undercloud registry there have been reports of container image pulls failing leading to the deployment failing.

Having paunch do image pull retries with exponential backoff would significantly reduce the chance of this happening.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/548230

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/548230
Committed: https://git.openstack.org/cgit/openstack/paunch/commit/?id=5c7a785053b96cf1faf3eee5b673f90a71a2f056
Submitter: Zuul
Branch: master

commit 5c7a785053b96cf1faf3eee5b673f90a71a2f056
Author: Steve Baker <email address hidden>
Date: Tue Feb 27 11:17:04 2018 +0000

    Use tenacity to retry image pulls

    Image pulls often fail due to network or registry load. This change
    implements pull retries, up to 4 times with jittered exponential
    backoff.

    Closes-Bug #1752036

    Change-Id: I09c601f357200e734aa9d887c6ce6b4e53fc2589

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/queens
Review: https://review.openstack.org/550249

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/550249
Committed: https://git.openstack.org/cgit/openstack/paunch/commit/?id=5697cbe9d946b6244f7e53f7c29e9c95ee4539b3
Submitter: Zuul
Branch: stable/queens

commit 5697cbe9d946b6244f7e53f7c29e9c95ee4539b3
Author: Steve Baker <email address hidden>
Date: Tue Feb 27 11:17:04 2018 +0000

    Use tenacity to retry image pulls

    Image pulls often fail due to network or registry load. This change
    implements pull retries, up to 4 times with jittered exponential
    backoff.

    Closes-Bug #1752036

    Change-Id: I09c601f357200e734aa9d887c6ce6b4e53fc2589
    (cherry picked from commit 5c7a785053b96cf1faf3eee5b673f90a71a2f056)