Volume claim on GKE / Multi-Attach error for volume Volume is already exclusively attached

Question

The problem seems to have been solved a long time ago, as the answer and the comments does not provide real solutions, I would like to get some help from experienced users

The error is the following (when describing the pod, which keeps on the ContainerCreating state) :

Multi-Attach error for volume "pvc-xxx" Volume is already exclusively attached to one node and can't be attached to another 

This all run on GKE. I had a previous cluster, and the problem never occured. I have reused the same disk when creating this new cluster — not sure if it is related

Here is the full yaml config files (I'm leaving the concerned code part commented as to highlight it; it is not when in effective use)

Thanks in advance if obvious workarounds

Answer 1

Based on your description what you are experiencing is exactly what is supposed to happen.

You are using gcePersistentDisk in your PV/PVC definition. The accessMode is ReadWriteOnce - this means that this PV can only be attached to a single Node (stressing Node here, there can be multiple Pods running on the same Node using the same PV). There is not much you can do about this; gcePersistentDisk is like a remote block device, it's not possible to mount it on multiple Nodes simultaneously (unless read only).

There is a nice table that shows which PVs support ReadWriteMany (that is, write access on multiple Nodes at the same time):

Important! A volume can only be mounted using one access mode at a time, even if it supports many. For example, a GCEPersistentDisk can be mounted as ReadWriteOnce by a single node or ReadOnlyMany by many nodes, but not at the same time.