Release variables have the highest precende in oooq and cannot be dynamically redifined.

[Sofer Athlan-Guyot]

Hi,

the release file is loaded using "-e ...", this gives it the highest precedence in ansible[1]. In case of mixed upgrade, this mechanism prevent us to reload any role with different variables' value. To overcome this we have to create other variable that are not present is the release file to be able to choose between values..

[1] https://docs.ansible.com/ansible/latest/playbooks_variables.html#variable-precedence-where-should-i-put-a-variable

[Sofer Athlan-Guyot (sofer-athlan-guyot)]

Not sure why the entry is not created automatically: https://review.openstack.org/#/c/540473/

[wes hayutin (weshayutin)]

@sofer we are working on https://review.openstack.org/#/c/543031/ to address the issue in holistic way

[wes hayutin (weshayutin)]

hrm.. maybe better to look at https://review.openstack.org/#/c/545072/

[Sofer Athlan-Guyot (sofer-athlan-guyot)]

Adding that https://review.openstack.org/#/c/526000/ as requested.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/540473
Committed: https://git.openstack.org/cgit/openstack/tripleo-quickstart-extras/commit/?id=33cf682ebb2a56c62cc7df0b6ba9170e1460f74e
Submitter: Zuul
Branch: master

commit 33cf682ebb2a56c62cc7df0b6ba9170e1460f74e
Author: Sofer Athlan-Guyot <email address hidden>
Date: Fri Feb 2 19:03:25 2018 +0100

    Add support to mixed upgrade for overcloud-prep-container role.

    During mixed version upgrade, we want to deploy the overcloud with the
    N-1 release docker images and then switch to the N release images
    file.

    That review[1] added the N-1 necessary tags. That review[2] was an
    attempt to use the proper parameters in that role for deployment in the
    context of mixed version. This fails.

    The failure comes from the fact that we load the release file using
    "-e ". All those variables then have the highest precedence[3]
    possible and cannot be overridden.

    Furthermore we use `use_overcloud_mixed_upgrade` flag to prevent the
    yum upgrade to run inside container during initial overcloud
    deployment. The problem here is that the repo configuration is taken
    from the undercloud which is N. Thus the N-1 images are upgraded to
    N. That means that we can't gate "from" patches. In a p->q setup, a
    change in pike cannot be tested if it relates to the docker image.

    Eventually we need a way to run the container role even when the
    containerized_overcloud is false. For Fast Forward Upgrade, the
    starting point is Newton which doesn't use container. So we introduce
    `prep_container_upgrade_run` flag that can be set from the featureset
    to ensure that the container get deployed during upgrade.

    [1] https://review.openstack.org/#/c/537833/
    [2] https://review.openstack.org/#/c/539920/1/toci-quickstart/playbooks/multinode-overcloud-prep.yml
    [3] https://docs.ansible.com/ansible/latest/playbooks_variables.html#variable-precedence-where-should-i-put-a-variable

    Related-Bug: #1745348

    This Tech-debt is introduced until the refactor of the release loading
    is done.
    Related-Bug: #1749978

    Change-Id: I4df06c8a0d5d8133ba64c38b90cef34793776422