In this article I will discuss how to manually scale an OpenShift IPI up or down depending on your needs. It is very easy to do with the oc binary via the command line. Whether you need to scale up your worker nodes to support more workloads or scale down to save on costs it can be done with one command.
First we need to login to our cluster via the oc command line utility.
oc login https://api.ocp4.example.com:6443
Next we need to get the name of the machineset for our cluster that we will be scaling.
oc get machinesets -n openshift-machine-api
This will return the name of our machinset as seen in the screenshot below.
Then we can run the following command to scale the cluster up or down adjusting the replicas=X portion of the command. Where X is the number of replicas to scale up or down to. You also need to adjust the machineset name to the one from the above command.
oc scale --replicas=4 ocp4-tkqrm-worker -n openshift-machine-api
You can use the oc get command from above to watch for the additional nodes to be added or removed depending on what you choice to do this will take some time. Do note that you can NOT scale to zero worker nodes without moving the router pods.