Using --limit option in external update/upgrade run playbooks has no effect on limiting nodes during ansible playbook execution

[Mikolaj Ciecierski]

Description
===========

As a part of update/upgrade procedure, some update steps are triggered using `openstack overcloud external-update/upgrade run` command. The implementation of external-upgrade/update run command accepts a --limit parameter, which identifies a list of nodes that the config-download Ansible playbook execution will be limited to[1]. However, external update/upgrade playbooks are run from the undercloud as a controller, and tasks are run with the use of ansible delegation mechanism (using delegate_to) on nodes that belongs to a certain group from tripleo-ansible-inventory.

For instance,`openstack overcloud external-update run --tags ovn`, which allows limiting the scope of update actions to updating ovn container image on overcloud nodes[2] loops through ovn_controller group from tripleo inventory. If one would like to limit container image update action to happen only on some set of nodes from the ovn_controller group by using --limit option, it won't work and skip execution completly due to 'skipping: no hosts matched' problem.

Steps to reproduce
==================
1. Run overcloud update prepare
2. Run `external-update run`

openstack overcloud external-update run \
    --stack overcloud \
    --ssh-user stack \
    --limit compute-0 \
    --tags ovn

Expected result
===============
Execution of the steps from external-update should happen only on compute-0

Actual result
=============
None external update step is triggered and 'no hosts matched' info is returned by ansible playbook execution.

2022-09-06 04:47:40.402 697741 INFO tripleoclient.utils.utils [-] Running ansible with the following limit: compute-0

PLAY [Check if required variables are defined] *********************************
skipping: no hosts matched

PLAY [Clear cached facts] ******************************************************

PLAY [Gather facts] ************************************************************

PLAY [Load global variables] ***************************************************
2022-09-06 04:47:41.260427 | fa163ea5-485e-6193-7e50-000000000019 | OK | ansible.builtin.include_vars | compute-0
2022-09-06 04:47:41.261041 | fa163ea5-485e-6193-7e50-000000000019 | TIMING | ansible.builtin.include_vars | compute-0 | 0:00:00.163284 | 0.03s

PLAY [Include extra variables from files] **************************************
2022-09-06 04:47:41.294549 | fa163ea5-485e-6193-7e50-00000000001c | TASK | Include Service VIP vars
2022-09-06 04:47:41.317498 | fa163ea5-485e-6193-7e50-00000000001c | OK | Include Service VIP vars | compute-0
2022-09-06 04:47:41.318270 | fa163ea5-485e-6193-7e50-00000000001c | TIMING | Include Service VIP vars | compute-0 | 0:00:00.220512 | 0.02s
2022-09-06 04:47:41.326823 | fa163ea5-485e-6193-7e50-00000000001d | TASK | Include OVN bridge MAC address variables
2022-09-06 04:47:41.349584 | fa163ea5-485e-6193-7e50-00000000001d | OK | Include OVN bridge MAC address variables | compute-0
2022-09-06 04:47:41.350133 | fa163ea5-485e-6193-7e50-00000000001d | TIMING | Include OVN bridge MAC address variables | compute-0 | 0:00:00.252377 | 0.02s

PLAY [Render all_nodes data as group_vars for overcloud] ***********************
2022-09-06 04:47:41.407274 | fa163ea5-485e-6193-7e50-000000000020 | TASK | Render all_nodes data as group_vars for overcloud
2022-09-06 04:47:42.259358 | fa163ea5-485e-6193-7e50-000000000020 | OK | Render all_nodes data as group_vars for overcloud | compute-0 -> localhost

PLAY [Set all_nodes data as group_vars for overcloud] **************************
2022-09-06 04:47:42.297324 | fa163ea5-485e-6193-7e50-000000000023 | TASK | Set all_nodes data as group_vars for overcloud
2022-09-06 04:47:42.321333 | fa163ea5-485e-6193-7e50-000000000023 | OK | Set all_nodes data as group_vars for overcloud | compute-0
2022-09-06 04:47:42.322031 | fa163ea5-485e-6193-7e50-000000000023 | TIMING | Set all_nodes data as group_vars for overcloud | compute-0 | 0:00:01.224272 | 0.02s

PLAY [External update step 0] **************************************************
skipping: no hosts matched

PLAY [External update step 1] **************************************************
skipping: no hosts matched

PLAY [External deploy step 1] **************************************************
skipping: no hosts matched

PLAY [External deploy step 2] **************************************************
skipping: no hosts matched

PLAY [External deploy step 3] **************************************************
skipping: no hosts matched

PLAY [External deploy step 4] **************************************************
skipping: no hosts matched

PLAY [External deploy step 5] **************************************************
skipping: no hosts matched

PLAY RECAP *********************************************************************
compute-0 : ok=5 changed=0 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
2022-09-06 04:47:42.356363 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Summary Information ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2022-09-06 04:47:42.356641 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Total Tasks: 5 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2022-09-06 04:47:42.356882 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Elapsed Time: 0:00:01.259131 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2022-09-06 04:47:42.357136 | UUID | Info | Host | Task Name | Run Time
2022-09-06 04:47:42.357429 | fa163ea5-485e-6193-7e50-000000000019 | SUMMARY | compute-0 | ansible.builtin.include_vars | 0.03s
2022-09-06 04:47:42.357666 | fa163ea5-485e-6193-7e50-000000000023 | SUMMARY | compute-0 | Set all_nodes data as group_vars for overcloud | 0.02s
2022-09-06 04:47:42.357933 | fa163ea5-485e-6193-7e50-00000000001c | SUMMARY | compute-0 | Include Service VIP vars | 0.02s
2022-09-06 04:47:42.358215 | fa163ea5-485e-6193-7e50-00000000001d | SUMMARY | compute-0 | Include OVN bridge MAC address variables | 0.02s
2022-09-06 04:47:42.358484 | fa163ea5-485e-6193-7e50-000000000020 | SUMMARY | compute-0 | Render all_nodes data as group_vars for overcloud | 0.00s
2022-09-06 04:47:42.358728 | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ End Summary Information ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2022-09-06 04:47:42.541 697741 INFO tripleoclient.utils.utils [-] Temporary directory [ /tmp/tripleopb6k3bfg ] cleaned up
2022-09-06 04:47:42.541 697741 INFO tripleoclient.utils.utils [-] Ansible execution success. playbook: /home/stack/overcloud-deploy/overcloud/config-download/tripleo-multi-playbook.yaml
2022-09-06 04:47:42.568 697741 INFO tripleoclient.v1.overcloud_external_update.ExternalUpdateRun [-] Completed Overcloud External Update Run.
2022-09-06 04:47:42.569 697741 INFO osc_lib.shell [-] END return value: None
[Tue Sep 6 04:47:42 AM EDT 2022] Finished OVN controller update

Environment
===========

Overcloud with OVN
Mater branch used, but the same behavior observed in previous versions(wallaby,train)

[1]https://github.com/openstack/python-tripleoclient/blob/master/tripleoclient/v1/overcloud_external_update.py#L95
https://github.com/openstack/python-tripleoclient/blob/master/tripleoclient/v1/overcloud_external_upgrade.py#L95
[2]https://opendev.org/openstack/tripleo-heat-templates/src/branch/master/deployment/ovn/ovn-controller-container-puppet.yaml#L464