11.2.2. Migrating Machine API resources to Cluster API resources

On clusters that support migrating Machine API resources to Cluster API resources, a two-way synchronization controller creates the following Cluster API resources in the openshift-cluster-api namespace:

These Cluster API resources correspond to the resources that the installation program provisions in the openshift-machine-api namespace for a cluster that uses the default configuration options. The Cluster API resources have the same names as their Machine API counterparts and appear in the output of commands, such as oc get, that list resources. The synchronization controller creates the Cluster API resources in an unprovisioned (Paused) state to prevent unintended reconciliation.

For supported configurations, you can migrate a Machine API resource to the equivalent Cluster API resource by changing which API it considers authoritative. When you migrate a Machine API resources to the Cluster API, you transfer management of the resource to the Cluster API.

By migrating a Machine API resource to use the Cluster API, you can verify that everything works as expected before deciding to use the Cluster API in production clusters. After migrating a Machine API resource to an equivalent Cluster API resource, you can examine the new resource to verify that the features and configuration match the original Machine API resource.

When you change the authoritative API for a compute machine set, any existing compute machines that the compute machine set manages retain their original authoritative API. As a result, a compute machine set that manages machines that use different authoritative APIs is a valid and expected occurrence in clusters that support migrating between these API types.

When you change the authoritative API for a compute machine, the instance on the underlying infrastructure that backs the machine is not recreated or reprovisioned. In-place changes, such as modifying labels, tags, taints, or annotations, are the only changes that the API group can make to the underlying instance that backs the machine.