How to include "readonly" and selinux context ":z" in kubernetes pod definition ?

Issue

• How to include "readonly" and selinux context ":z" in kubernetes pod definition ?

Snip from the pod definition

volumeMounts:
      - name: storage
        mountPath: /storage
      - name: secret
        readOnly: true
        mountPath: /secret:z                 

While deploying the pod, following message is seen in the logs

Mar 24 17:01:22 XXXXX docker[2242]: time="2016-03-24T17:01:22.895864834Z" level=error msg="Handler for POST /containers/{name:.*}/start returned error: Invalid volume specification: /var/lib/kubelet/pods/17182cf7-f1d5-11e5-8219-5254006f3eb2/volumes/kubernetes.io~secret/secret:/secret:z:ro"