Check what error message is shown in the UI when a session cannot be scheduled because PVC mount limit per node is reached

[olevski]

From Rok:

one thing we didn’t flag in today’s discussion: openstack volume limit per node is 25. One of the reasons we wanted resource classes is so we can control better how many sessions we can fit on a node, and this shouldn’t be a problem for our deployments. But if we configure beefier nodes at one point, it might be. Thoughts?

This is related to the fact that nodes in openstack on our cluster have a limit of max 25 volumes being mounted at the same time. When this limit is reached we should make sure we properly forward the error message to the user.

We should test what error shows up in the UI when this happens. If the proper error does not show up then we should make changes so that it does show up.