If you are not familiar with the oc command, refer to OpenShift - Getting Started with the oc command.

A node contains one or more pods, and each pod contains one or more containers.

The oc describe pod/pod_name command can be used to view a pods configuration.

oc describe pod/pod001

Something like this should be returned, in the JSON format by default. Notice in this example the JAVA_OPTS contains -Xmx512m and -Xms256m, meaning that the pods has 512 MB of memory allocated for the heap and 256 MB of memory allocated for metaspace.

    Environment:
      JAVA_OPTS: -Xmx512m -Xms256m

The oc edit command can be used to edit the pods configuration.

oc edit pod/pod001

Let's say you update the pod to have 128 MB of memory allocated for metaspace.

JAVA_OPTS: -Xmx512m -Xms128m

After this change has been made, you will want to restart the pod (scale down, then up) for this change to take effect.