Here are a few handy commands to check and see how much cpu and memory your Openshift cluster is using.

Node Utilisation

$ oc adm top node will show how much memory and cpu your nodes are using.

$ oc describe node/$nodeName will give details about the allocated resources:

This can be shortened to the following command:

Pod Utilisation

$ oc adm top pod will give an idea of which pods are the most hungry. Omnomnom.

We can also break this down to a node level by extracting the information from oc describe node with the following:

Hope that was helpful :o)