I've tried running 2 Kubernetes pods on a single-node GKE cluster, sharing a read-only GCE persistent disk, but while one pod successfully runs, the other is stuck in the ContainerCreating state.

The container is very simple:

FROM debian:jessie
CMD ["/bin/sh", "-c", "while true; do ls /mount; sleep 5; done"]

The deployment looks like this:

apiVersion: extensions/v1beta1 kind: Deployment metadata: name: dumpy spec: replicas: 2 template: metadata: labels: app: dump spec: containers: - name: dump image: gcr.io/myproject/dump volumeMounts: - mountPath: /mount name: dump readOnly: true volumes: - name: dump gcePersistentDisk: pdName: my-disk fsType: ext4 readOnly: true

The failed pod reports:

Warning     FailedMount Unable to mount volumes for pod "xxx". Could not attach GCE PD "my-disk". Timeout waiting for mount paths to be created.
FailedSync  Error syncing pod, skipping: Could not attach GCE PD "my-disk". Timeout waiting for mount paths to be created.

/var/log/kubelet.log reports:

gce.go:422] GCE operation failed: googleapi: Error 400: The disk resource 'my-disk' is already being used by 'xxx-123'
gce_util.go:187] Error attaching PD "my-disk": googleapi: Error 400: The disk resource 'my-disk' is already being used by 'xxx-123'

I believe the Kubernetes documentation explicitly allows this scenario.

A feature of PD is that they can be mounted as read-only by multiple consumers simultaneously. This means that you can pre-populate a PD with your dataset and then serve it in parallel from as many pods as you need.

What's going on and what's the fix?