Addressing an Overlooked Test Case: Reevaluating Pre-operation Checks in Recent Patch

[Nguyen Ngoc Hieu]

I missed a test case in my recent patch. It happens when ignoring pre_op LB if the cluster is already at the minimum size [https://github.com/openstack/senlin/commit/23f3bd708b5c7026051c2635f34ee69b5c366a2a]. Let me briefly describe this patch:
- The pre_op check actions include: CLUSTER_DEL_NODES, CLUSTER_SCALE_IN, CLUSTER_RESIZE, NODE_DELETE, CLUSTER_REPLACE_NODES.
- The actions among the above will skip the pre_op check if the cluster is already at the minimum size: CLUSTER_DEL_NODES, CLUSTER_SCALE_IN, CLUSTER_RESIZE, NODE_DELETE.
- The exception action is CLUSTER_REPLACE_NODES.

However, I quickly realized that the CLUSTER_RESIZE action should be an exception for the following reasons:
- Resizing a cluster that already has desired_capacity = min_size is still entirely valid.
- CLUSTER_RESIZE allows simultaneous changes to both desired_capacity and min_size, and they have been validated in the conductor [https://github.com/openstack/senlin/blob/29f2e885e7648934dfd46196bb6f25e08d5857ad/senlin/conductor/service.py#L1149C14-L1149C14].

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/senlin/+/905429

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/senlin/+/905429
Committed: https://opendev.org/openstack/senlin/commit/7ef513dd7918b609abf19712288c3bc98405fb67
Submitter: "Zuul (22348)"
Branch: master

commit 7ef513dd7918b609abf19712288c3bc98405fb67
Author: Nguyen Ngoc Hieu <email address hidden>
Date: Fri Jan 12 17:26:43 2024 +0700

    Removing CLUSTER_RESIZE from pre-op skip List at min threshold

    Excluding CLUSTER_RESIZE from the list of actions that skip
    pre-operation checks if the cluster is already at the minimum threshold.

    When the cluster is at the minimum threshold, pre-op LB will function
    with actions such as CLUSTER_DEL_NODES, CLUSTER_SCALE_IN, NODE_DELETE,
    and will skip actions like CLUSTER_REPLACE_NODES and CLUSTER_RESIZE.

    Closes-Bug: #2049191
    Change-Id: I00a7ea40f69bafc94ca2bba9f268af7b03344997