Unable to add a subcloud with mixed docker_registries configuration

[Tee Ngo]

Brief Description
-----------------
Unable to add a subcloud with mixed docker_registries configuration such as:

docker_registries:
  k8s.gcr.io:
    url: myaws.private.com/k8s.gcr.io
    type: aws-ecr
    username: test_registry_user
    password: St8rlingX*
  gcr.io:
    url: myaws.private.registry.com/gcr.io
    type: aws-ecr
    username: test_registry_user
    password: St8rlingX*
  quay.io:
    url: quay.io
  docker.io:
    url: docker.io
  docker.elastic.co:
    url: myaws.private.registry.com/docker.elastic.co
    type: aws-ecr
    username: test_registry_user
    password: St8rlingX*
  ghcr.io:
    url: myaws.private.registry.com/ghcr.io
    type: aws-ecr
    username: test_registry_user
    password: St8rlingX*
  defaults:
    type: docker

Severity
--------
Critical

Steps to Reproduce
------------------
Add a subcloud with mixed docker_registries configuration (authenticated and unauthenticated registry sources)

Expected Behavior
------------------

Actual Behavior
----------------
Subcloud bootstrap fails with the following ansible error

TASK [bootstrap/persist-config : Create Barbican secret for elastic registry if credentials exist] ***
Thursday 03 February 2022 20:23:10 +0000 (0:00:00.015) 0:01:27.138 *****
fatal: [subcloud1]: FAILED! =>
  msg: |-
    The task includes an option with an undefined variable. The error was: 'dict object' has no attribute 'username'

    The error appears to have been in '/usr/share/ansible/stx-ansible/playbooks/roles/bootstrap/persist-config/tasks/main.yml': line 184, column 5, but may
    be elsewhere in the file depending on the exact syntax problem.

    The offending line appears to be:

    - block:
      - name: Create Barbican secret for elastic registry if credentials exist
        ^ here

PLAY RECAP *********************************************************************
subcloud1 : ok=177 changed=45 unreachable=0 failed=1

Reproducibility
---------------
100% reproducible

System Configuration
--------------------
Distributed Cloud

Branch/Pull Time/Commit
-----------------------
Feb. 02, 2022 master build

Last Pass
---------
This configuration has never been verified before

Timestamp/Logs
--------------
See error log above

Test Activity
-------------
Feature Testing

Workaround
----------
None

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/starlingx/ansible-playbooks/+/827888

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/starlingx/ansible-playbooks/+/827888
Committed: https://opendev.org/starlingx/ansible-playbooks/commit/6ee214d92751811657521a45655fefd5825bcf45
Submitter: "Zuul (22348)"
Branch: master

commit 6ee214d92751811657521a45655fefd5825bcf45
Author: Tee Ngo <email address hidden>
Date: Fri Feb 4 12:04:21 2022 -0500

    Fix bootstrap issue related to mixed registry config

    This commit fixes the mishandling of docker_registries config
    where elastic and ghcr registries are authenticated and docker
    registry is unauthenticated.

    Test plan:
      - Deploy a subcloud with mixed docker_registries config
        as described in LP1960063.
      - Deploy a subcloud with central registry as docker
        registries source.

    Closes-Bug: 1960063
    Change-Id: I0811c45a028aba51e7da4fbf5c9e91a1b5496f5f
    Signed-off by: Tee Ngo <email address hidden>