OCPBUGS-99650: Delete stale auto-sizing MachineConfigs for non-default (custom) pools 4.20

[aksjadha]

Fixes: OCPBUGS-99650

- What I did

Fixed stale 50-{pool}-auto-sizing-disabled MachineConfigs persisting on non-default pools after upgrade from 4.20.24 or earlier. Restarting machine-config-controller creating 50-{pool}-auto-sizing-disabled MachineConfigs for custom pools.

OCPBUGS-83862 (shipped in 4.20.25) stopped creating auto-sizing MachineConfigs for non-default pools, but never cleaned up ones already created by older MCO versions. These stale MachineConfigs mask autoscaling configuration in KubeletConfigs for custom pool nodes.

Modified ensureAutoSizingMachineConfigs to iterate all MachineConfigPools on controller startup:

• Master/worker pools: create auto-sizing MC if missing (existing behavior)
• Non-default pools: delete the auto-sizing MC if it exists

- How to verify it

1. Launch a cluster on 4.20.24
2. oc apply -f mcp.yaml to add a custom MachineConfigPool
3. oc -n openshift-machine-config-operator delete pods -l k8s-app=machine-config-controller
4. Verify 50-custom-auto-sizing-disabled gets created
5. Upgrade to a version containing this fix
6. oc get machineconfigs | grep auto-sizing — only 50-master-auto-sizing-disabled and 50-worker-auto-sizing-disabled should remain

- Description for the changelog

Delete stale auto-sizing-disabled MachineConfigs for non-default pools on controller startup to fix custom pool nodes affected after upgrade clusters.

[openshift-merge-bot]

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[openshift-ci]

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[openshift-ci-robot]

@aksjadha: This pull request references Jira Issue OCPBUGS-99650, which is invalid:

• release note text must be set and not match the template OR release note type must be set to "Release Note Not Required". For more information you can reference the OpenShift Bug Process.
• expected Jira Issue OCPBUGS-99650 to depend on a bug targeting a version in 4.21.0, 4.21.z and in one of the following states: VERIFIED, RELEASE PENDING, CLOSED (ERRATA), CLOSED (CURRENT RELEASE), CLOSED (DONE), CLOSED (DONE-ERRATA), but no dependents were found

Comment /jira refresh to re-evaluate validity if changes to the Jira bug are made, or edit the title of this pull request to link to a different bug.

The bug has been updated to refer to the pull request using the external bug tracker.

Details

In response to this:

Fixes: OCPBUGS-99650

- What I did

Fixed stale 50-{pool}-auto-sizing-disabled MachineConfigs persisting on non-default pools after upgrade from 4.20.24 or earlier. Restarting machine-config-controller creating 50-{pool}-auto-sizing-disabled MachineConfigs for custom pools.

OCPBUGS-83862 (shipped in 4.20.25) stopped creating auto-sizing MachineConfigs for non-default pools, but never cleaned up ones already created by older MCO versions. These stale MachineConfigs mask autoscaling configuration in KubeletConfigs for custom pool nodes.

Modified ensureAutoSizingMachineConfigs to iterate all MachineConfigPools on controller startup:

• Master/worker pools: create auto-sizing MC if missing (existing behavior)
• Non-default pools: delete the auto-sizing MC if it exists

- How to verify it

1. Launch a cluster on 4.20.24
2. oc apply -f mcp.yaml to add a custom MachineConfigPool
3. oc -n openshift-machine-config-operator delete pods -l k8s-app=machine-config-controller
4. Verify 50-custom-auto-sizing-disabled gets created
5. Upgrade to a version containing this fix
6. oc get machineconfigs | grep auto-sizing — only 50-master-auto-sizing-disabled and 50-worker-auto-sizing-disabled should remain

- Description for the changelog

Delete stale auto-sizing-disabled MachineConfigs for non-default pools on controller startup to fix custom pool nodes affected after upgrade clusters.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the openshift-eng/jira-lifecycle-plugin repository.

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[aksjadha]

Manually verified that the MCC is working as expected. During MCC reconciliation, the older custom autosizing MachineConfig is removed, leaving only the master and worker autosizing MachineConfigs.

# oc get clusterversion
NAME      VERSION                                                AVAILABLE   PROGRESSING   SINCE   STATUS
version   4.20.0-0-2026-07-24-084507-test-ci-ln-71zxh7t-latest   True        False         44m     Cluster version is 4.20.0-0-2026-07-24-084507-test-ci-ln-71zxh7t-latest

# oc get mc|grep 50      
50-custom-auto-sizing-disabled                                                                 3.5.0             16s
50-master-auto-sizing-disabled                                                                 3.5.0             62m
50-worker-auto-sizing-disabled                                                                 3.5.0             62m

# oc -n openshift-machine-config-operator delete pods -l k8s-app=machine-config-controller
pod "machine-config-controller-7649575fb4-b844r" deleted

# oc get mc|grep 50                                        
50-master-auto-sizing-disabled                                                                 3.5.0             63m
50-worker-auto-sizing-disabled                                                                 3.5.0             63m

Additionally, I deleted all three MachineConfigs (50-custom-auto-sizing-disabled, 50-master-auto-sizing-disabled, and 50-worker-auto-sizing-disabled). After restarting the MCC, only 50-master-auto-sizing-disabled and 50-worker-auto-sizing-disabled were recreated, confirming that the custom autosizing MachineConfig is no longer regenerated during reconciliation.

[aksjadha]

/jira refresh

[openshift-ci-robot]

@aksjadha: This pull request references Jira Issue OCPBUGS-99650, which is invalid:

• expected the bug to target either version "4.20." or "openshift-4.20.", but it targets "4.21.z" instead
• expected dependent Jira Issue OCPBUGS-99674 to target a version in 4.21.0, 4.21.z, but it targets "4.20.z" instead

Comment /jira refresh to re-evaluate validity if changes to the Jira bug are made, or edit the title of this pull request to link to a different bug.

Details

In response to this:

/jira refresh

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the openshift-eng/jira-lifecycle-plugin repository.

[aksjadha]

/jira refresh

[openshift-ci-robot]

@aksjadha: This pull request references Jira Issue OCPBUGS-99650, which is valid. The bug has been moved to the POST state.

7 validation(s) were run on this bug

• bug is open, matching expected state (open)
• bug target version (4.20.z) matches configured target version for branch (4.20.z)
• bug is in the state ASSIGNED, which is one of the valid states (NEW, ASSIGNED, POST)
• release note text is set and does not match the template
• dependent bug Jira Issue OCPBUGS-99674 is in the state Closed (Done), which is one of the valid states (VERIFIED, RELEASE PENDING, CLOSED (ERRATA), CLOSED (CURRENT RELEASE), CLOSED (DONE), CLOSED (DONE-ERRATA))
• dependent Jira Issue OCPBUGS-99674 targets the "4.21.z" version, which is one of the valid target versions: 4.21.0, 4.21.z
• bug has dependents

Details

In response to this:

/jira refresh

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the openshift-eng/jira-lifecycle-plugin repository.

[aksjadha]

/ok-to-test

[openshift-ci-robot]

@aksjadha: This pull request references Jira Issue OCPBUGS-99650, which is valid.

7 validation(s) were run on this bug

• bug is open, matching expected state (open)
• bug target version (4.20.z) matches configured target version for branch (4.20.z)
• bug is in the state POST, which is one of the valid states (NEW, ASSIGNED, POST)
• release note text is set and does not match the template
• dependent bug Jira Issue OCPBUGS-99674 is in the state Closed (Done), which is one of the valid states (VERIFIED, RELEASE PENDING, CLOSED (ERRATA), CLOSED (CURRENT RELEASE), CLOSED (DONE), CLOSED (DONE-ERRATA))
• dependent Jira Issue OCPBUGS-99674 targets the "4.21.z" version, which is one of the valid target versions: 4.21.0, 4.21.z
• bug has dependents

Details

In response to this:

Fixes: OCPBUGS-99650

- What I did

Fixed stale 50-{pool}-auto-sizing-disabled MachineConfigs persisting on non-default pools after upgrade from 4.20.24 or earlier. Restarting machine-config-controller creating 50-{pool}-auto-sizing-disabled MachineConfigs for custom pools.

OCPBUGS-83862 (shipped in 4.20.25) stopped creating auto-sizing MachineConfigs for non-default pools, but never cleaned up ones already created by older MCO versions. These stale MachineConfigs mask autoscaling configuration in KubeletConfigs for custom pool nodes.

Modified ensureAutoSizingMachineConfigs to iterate all MachineConfigPools on controller startup:

• Master/worker pools: create auto-sizing MC if missing (existing behavior)
• Non-default pools: delete the auto-sizing MC if it exists

- How to verify it

1. Launch a cluster on 4.20.24
2. oc apply -f mcp.yaml to add a custom MachineConfigPool
3. oc -n openshift-machine-config-operator delete pods -l k8s-app=machine-config-controller
4. Verify 50-custom-auto-sizing-disabled gets created
5. Upgrade to a version containing this fix
6. oc get machineconfigs | grep auto-sizing — only 50-master-auto-sizing-disabled and 50-worker-auto-sizing-disabled should remain

- Description for the changelog

Delete stale auto-sizing-disabled MachineConfigs for non-default pools on controller startup to fix custom pool nodes affected after upgrade clusters.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the openshift-eng/jira-lifecycle-plugin repository.

[aksjadha]

/retest

[pablintino]

/lgtm

[openshift-merge-bot]

Scheduling tests matching the pipeline_run_if_changed or not excluded by pipeline_skip_if_only_changed parameters:
/test e2e-aws-ovn
/test e2e-aws-ovn-upgrade
/test e2e-gcp-op-ocl
/test e2e-gcp-op-ocl-part1
/test e2e-gcp-op-ocl-part2
/test e2e-gcp-op-part1
/test e2e-gcp-op-part2
/test e2e-gcp-op-single-node
/test e2e-hypershift

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: aksjadha, pablintino

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• OWNERS [pablintino]

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[aksjadha]

/retest

[openshift-ci]

@aksjadha: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
ci/prow/e2e-gcp-op-ocl	e0d9dd7	link	false	/test e2e-gcp-op-ocl

Full PR test history. Your PR dashboard.

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