Enable MachineAPIMigration, update status.authoritativeAPI to MachineAPI, change mapi machineset instanceType from m6i.xlarge to m5.large, no change for awsmachinetemplate.  

4.19.0-0.ci-2025-04-07-182331

Always

1. Enable MachineAPIMigration
2. Manually update status.authoritativeAPI to MachineAPI
3. Update mapi machineset instanceType: m6i.xlarge to instanceType: m5.large  
3.
    

No awsmachinetemplate was recreated, the awsmachinetemplateinstanceType is still m6i.xlarge, not change.

$ oc get machineset.m -n openshift-machine-api zhsun-aws48-444p5-worker-us-east-2a -o yaml
status:
  authoritativeAPI: MachineAPI
  availableReplicas: 1
  conditions:
  - lastTransitionTime: "2025-04-08T04:03:20Z"
    message: The AuthoritativeAPI is set to MachineAPI
    reason: AuthoritativeAPIMachineAPI
    severity: Info
    status: "False"
    type: Paused
  - lastTransitionTime: "2025-04-08T04:15:48Z"
    message: 'failed to update CAPI infra machine template: admission webhook "validation.awsmachinetemplate.infrastructure.cluster.x-k8s.io"
      denied the request: AWSMachineTemplate.infrastructure.cluster.x-k8s.io "zhsun-aws48-444p5-worker-us-east-2a"
      is invalid: spec.template.spec: Invalid value: v1beta2.AWSMachineTemplate{TypeMeta:v1.TypeMeta{Kind:"AWSMachineTemplate",
      APIVersion:"infrastructure.cluster.x-k8s.io/v1beta2"}, ObjectMeta:v1.ObjectMeta{Name:"zhsun-aws48-444p5-worker-us-east-2a",
      GenerateName:"", Namespace:"openshift-cluster-api", SelfLink:"", UID:"66534b11-f232-44fd-981a-d3facf25419b",
      ResourceVersion:"114892", Generation:2, CreationTimestamp:time.Date(2025, time.April,
      8, 4, 3, 20, 0, time.Local), DeletionTimestamp:<nil>, DeletionGracePeriodSeconds:(*int64)(nil),
      Labels:map[string]string(nil), Annotations:map[string]string(nil), OwnerReferences:[]v1.OwnerReference{v1.OwnerReference{APIVersion:"cluster.x-k8s.io/v1beta1",
      Kind:"Cluster", Name:"zhsun-aws48-444p5", UID:"7bc5afc4-d5b3-4085-8e04-cce4381aaa5e",
      Controller:(*bool)(0xc0031b7057), BlockOwnerDeletion:(*bool)(0xc0031b7056)}},
      Finalizers:[]string(nil), ManagedFields:[]v1.ManagedFieldsEntry{v1.ManagedFieldsEntry{Manager:"machine-api-migration",
      Operation:"Update", APIVersion:"infrastructure.cluster.x-k8s.io/v1beta2", Time:time.Date(2025,
      time.April, 8, 4, 16, 49, 0, time.Local), FieldsType:"FieldsV1", FieldsV1:(*v1.FieldsV1)(0xc0031aa660),
      Subresource:""}}}, Spec:v1beta2.AWSMachineTemplateSpec{Template:v1beta2.AWSMachineTemplateResource{ObjectMeta:v1beta1.ObjectMeta{Labels:map[string]string(nil),
      Annotations:map[string]string(nil)}, Spec:v1beta2.AWSMachineSpec{ProviderID:(*string)(nil),
      InstanceID:(*string)(nil), InstanceMetadataOptions:(*v1beta2.InstanceMetadataOptions)(0xc0031aeac0),
      AMI:v1beta2.AMIReference{ID:(*string)(0xc002fdbb40), EKSOptimizedLookupType:(*v1beta2.EKSAMILookupType)(nil)},
      ImageLookupFormat:"", ImageLookupOrg:"", ImageLookupBaseOS:"", InstanceType:"m5.large",
      AdditionalTags:v1beta2.Tags{"kubernetes.io/cluster/zhsun-aws48-444p5":"owned"},
      IAMInstanceProfile:"zhsun-aws48-444p5-worker-profile", PublicIP:(*bool)(nil),
      ElasticIPPool:(*v1beta2.ElasticIPPool)(nil), AdditionalSecurityGroups:[]v1beta2.AWSResourceReference{v1beta2.AWSResourceReference{ID:(*string)(nil),
      Filters:[]v1beta2.Filter{v1beta2.Filter{Name:"tag:Name", Values:[]string{"zhsun-aws48-444p5-node"}}}},
      v1beta2.AWSResourceReference{ID:(*string)(nil), Filters:[]v1beta2.Filter{v1beta2.Filter{Name:"tag:Name",
      Values:[]string{"zhsun-aws48-444p5-lb"}}}}}, Subnet:(*v1beta2.AWSResourceReference)(0xc000988da0),
      SecurityGroupOverrides:map[v1beta2.SecurityGroupRole]string(nil), SSHKeyName:(*string)(nil),
      RootVolume:(*v1beta2.Volume)(0xc00308c0a0), NonRootVolumes:[]v1beta2.Volume(nil),
      NetworkInterfaces:[]string(nil), NetworkInterfaceType:"", UncompressedUserData:(*bool)(nil),
      CloudInit:v1beta2.CloudInit{InsecureSkipSecretsManager:false, SecretCount:0,
      SecretPrefix:"", SecureSecretsBackend:""}, Ignition:(*v1beta2.Ignition)(0xc0031aca50),
      SpotMarketOptions:(*v1beta2.SpotMarketOptions)(nil), PlacementGroupName:"",
      PlacementGroupPartition:0, Tenancy:"", PrivateDNSName:(*v1beta2.PrivateDNSName)(nil),
      CapacityReservationID:(*string)(nil), MarketType:""}}}, Status:v1beta2.AWSMachineTemplateStatus{Capacity:v1.ResourceList(nil)}}:
      AWSMachineTemplate.Spec is immutable'
    reason: FailedToUpdateCAPIInfraMachineTemplate
    severity: Error
    status: "False"
    type: Synchronized
  fullyLabeledReplicas: 1
  observedGeneration: 3
  readyReplicas: 1
  replicas: 1
  synchronizedGeneration: 2

A new awsmachinetemplate should be created. 

From Joel https://issues.redhat.com/browse/OCPCLOUD-2644?focusedId=26403166&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-26403166
The machine template name should be constructed based on a hash of the content within it, if the name of the machine template is just the name of the machineset for now