When a ControlPlaneMachineSet (CPMS) is in an Inactive state, any attempt to modify it, specifically to add or update the controlplanemachineset.spec.template.machines_v1beta1_machine_openshift_io.spec.providerSpec.value., results in the creation of a new CPMS. However, in this newly created CPMS, the capacityReservationId field is reset to a blank string ("") instead of retaining the value that was just applied. This prevents administrators from associating control plane machines with an AWS Capacity Reservation if the CPMS is in an Inactive state.

   4.19.2, AWS, IPI

    100%

1. Delete the existing ControlPlaneMachineSet:
$ oc delete controlplanemachinesets.machine.openshift.io cluster
controlplanemachineset.machine.openshift.io "cluster" deleted

This action forces the cluster to automatically recreate the resource.

2. Wait for the ControlPlaneMachineSet to be recreated:
After a few moments, the CPMS object is recreated, but it enters an Inactive state.
$ oc get controlplanemachineset
NAME      DESIRED   CURRENT   READY   UPDATED   UNAVAILABLE   STATE      AGE
cluster   3         3         3       1                     Inactive   4m
 
3. Edit the Inactive ControlPlaneMachineSet:
Modify the cluster CPMS to add a value for capacityReservationId:
$ oc edit controlplanemachineset cluster
      spec:
        lifecycleHooks: {}
        metadata: {}
        providerSpec:
          value:
            capacityReservationId: "cr-06f0dfdbd1de87694"
...
...

controlplanemachineset.machine.openshift.io/cluster edited

4. Upon saving the changes, observe that a new CPMS resource is immediately created. 

$ oc get controlplanemachineset
NAME      DESIRED   CURRENT   READY   UPDATED   UNAVAILABLE   STATE      AGE
cluster   3         3         3       1                       Inactive   2s

5. Verify the capacityReservationId:
$ oc get controlplanemachineset cluster  -o yaml | grep capacity -i
            capacityReservationId: ""

    The capacityReservationId field in the new ControlPlaneMachineSet is blank, ignoring the value that was applied during the edit.          capacityReservationId: ""

    The capacityReservationId field in the ControlPlaneMachineSet should be populated with the value provided during the oc edit operation. The configuration change should be successfully applied and retained.          capacityReservationId: "your-reservation-id"