The GCE PD plugin uses safe_format_and_mount found on standard GCE images:

https://github.com/GoogleCloudPlatform/compute-image-packages/blob/master/google-startup-scripts/usr/share/google/safe_format_and_mount

On custom images where this is not available pods fail to format and
mount GCE PDs. This patch uses linux utilities in a similar way to the
safe_format_and_mount script to format and mount the GCE PD and AWS EBC
devices. That is first attempt a mount. If mount fails try to use file to
investigate the device. If 'file' fails to get any information about
the device and simply returns "data" then assume the device is not
formatted and format it and attempt to mount it again.
Signed-off-by: Sami Wagiaalla <swagiaal@redhat.com>