Chapter 3. Manually scaling a machine set You can add or remove an instance of a machine in a machine set. Note If you need to modify aspects of a machine set outside of scaling, see Modifying a machine set . 3.1. Prerequisites If you enabled the cluster-wide proxy and scale up workers not included in networking.machineNetwork[].cidr from the installation configuration, you must add the workers to the Proxy object's noProxy field to prevent connection issues. Important This process is not applicable for clusters with manually provisioned machines. You can use the advanced machine management and scaling capabilities only in clusters where the Machine API is operational. 3.2. Scaling a machine set manually To add or remove an instance of a machine in a machine set, you can manually scale the machine set. This guidance is relevant to fully automated, installer-provisioned infrastructure installations. Customized, user-provisioned infrastructure installations do not have machine sets. Prerequisites Install an OpenShift Container Platform cluster and the oc command line. Log in to oc as a user with cluster-admin permission. Procedure View the machine sets that are in the cluster: USD oc get machinesets -n openshift-machine-api The machine sets are listed in the form of <clusterid>-worker-<aws-region-az> . View the machines that are in the cluster: USD oc get machine -n openshift-machine-api Set the annotation on the machine that you want to delete: USD oc annotate machine/<machine_name> -n openshift-machine-api machine.openshift.io/cluster-api-delete-machine="true" Cordon and drain the node that you want to delete: USD oc adm cordon <node_name> USD oc adm drain <node_name> Scale the machine set: USD oc scale --replicas=2 machineset <machineset> -n openshift-machine-api Or: USD oc edit machineset <machineset> -n openshift-machine-api You can scale the machine set up or down. It takes several minutes for the new machines to be available. Verification Verify the deletion of the intended machine: USD oc get machines 3.3. The machine set deletion policy Random , Newest , and Oldest are the three supported deletion options. The default is Random , meaning that random machines are chosen and deleted when scaling machine sets down. The deletion policy can be set according to the use case by modifying the particular machine set: spec: deletePolicy: <delete_policy> replicas: <desired_replica_count> Specific machines can also be prioritized for deletion by adding the annotation machine.openshift.io/cluster-api-delete-machine=true to the machine of interest, regardless of the deletion policy. Important By default, the OpenShift Container Platform router pods are deployed on workers. Because the router is required to access some cluster resources, including the web console, do not scale the worker machine set to 0 unless you first relocate the router pods. Note Custom machine sets can be used for use cases requiring that services run on specific nodes and that those services are ignored by the controller when the worker machine sets are scaling down. This prevents service disruption.

Commands:
oc get machinesets -n openshift-machine-api
oc get machine -n openshift-machine-api
oc annotate machine/<machine_name> -n openshift-machine-api machine.openshift.io/cluster-api-delete-machine="true"
oc adm cordon <node_name> oc adm drain <node_name>
oc scale --replicas=2 machineset <machineset> -n openshift-machine-api
oc edit machineset <machineset> -n openshift-machine-api
oc get machines
spec: deletePolicy: <delete_policy> replicas: <desired_replica_count>