I created a war (using Rest War generator) in Designer and added it to my project. Then to deploy it, I selected it and used the 'Mark as Deployable" action.

This worked fine on my local server (both deploy and undeploy) but then I switched to an OpenShift external server instance (used port-forwarding).

The 'Mark as Deployable' action doesnt work for the Openshift external server. Maybe the action is doing a copy of the war into the deployments folder?

We don't provide the action, but we should either troubleshoot or potentially provide our own action which deploys a war using the admin api.