Configured docker size is not respected during bootstrap over simplex upgrade

[Heitor Matsui]

Brief Description
-----------------
Docker size is set to a fixed value of 20G as opposed to the size configured by the user during bootstrap (restore from backup) over simplex upgrade.

Severity
-----------------
Critical

Steps to Reproduce
-----------------
Distributed Cloud:
- Bring up a distributed cloud with at least 1 simplex subcloud
- Increase docker size on the subcloud to 40G using system host-fs-modify command
- Upgrade the system controller
- Upgrade the subcloud

Standalone simplex:
- Bring up an AIOSX
- Increase docker size on the subcloud
- Perform upgrade

Expected Behavior
-----------------
During bootstrap, docker size should be set to 40G as configured before the upgrade

Actual Behavior
-----------------
Docker size is set to a fixed value of 20G during bootstrap. If there are more than 3 image bundles, there is a good chance that there will not be not enough docker space to import the prestaged images. Consequently, the subcloud will default to pulling all images from the central registry/configured sources.

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

System Configuration
-----------------
AIO-SX, AIO-SX subcloud

Branch/Pull Time/Commit
-----------------
master

Last Pass
-----------------
N/A

Timestamp/Logs
-----------------
N/A, the issue is 100% reproducible

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

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

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/starlingx/ansible-playbooks/+/837612
Committed: https://opendev.org/starlingx/ansible-playbooks/commit/d2dba85b21394fc08cf20194bd3a96842fc4cfd6
Submitter: "Zuul (22348)"
Branch: master

commit d2dba85b21394fc08cf20194bd3a96842fc4cfd6
Author: Heitor Matsui <email address hidden>
Date: Tue Apr 12 15:23:03 2022 -0300

    Fetch docker lv_size from backup hieradata

    Currently the bootstrap recovers only a subset of hieradata
    from the backup file, namely the static and system yaml files.
    This, in turn, allows the bootstrap to configure the drbd
    filesystem sizes accordingly to the values configured by the
    user before the upgrade.

    This commit adds additional steps on bootstrap playbook to
    get docker lv_size from the backup tarball and include it
    on the runtime.yaml so that docker lv_size is configured
    during the bootstrap with the custom value provided by the
    user.

    Test Plan:
    PASS: 1. Increase docker filesystem prior to upgrade
          2. Upgrade AIO SX and verify that during bootstrap the
             docker filesystem is configured with custom value
             configured prior to the upgrade
    PASS: 1. Increase subcloud docker filesystem prior to upgrade
          2. Upgrade subcloud and verify that during bootstrap the
             docker filesystem is configured with custom value
             configured prior to the upgrade

    Closes-bug: 1968779
    Change-Id: Icbf5cf8773ce09b8ec830571167efe26e64f51fe
    Signed-off-by: Heitor Matsui <email address hidden>