Description of problem:
Glusterfs: unable install if docker storage driver is overlay2


Version-Release number of selected component (if applicable):
oc v3.7.0-0.126.4 (overlay2 as storage driver for docker)
kubernetes v1.7.0+80709908fd

openshift_storage_glusterfs_image=registry.access.redhat.com/rhgs3/rhgs-server-rhel7
openshift_storage_glusterfs_version=latest
openshift_storage_glusterfs_heketi_image=registry.access.redhat.com/rhgs3/rhgs-volmanager-rhel7
openshift_storage_glusterfs_heketi_version=latest

How reproducible:

Steps to Reproduce:
1. ansible-playbook -i inv.file openshift-ansible/playbooks/byo/config.yml


Actual results:

TASK [openshift_storage_glusterfs : Create heketi DB volume] ******************************************************************
fatal: [ec2-54-186-161-92.us-west-2.compute.amazonaws.com]: FAILED! => {
    "changed": true, 
    "cmd": [
        "oc", 
        "rsh", 
        "--namespace=glusterfs", 
        "deploy-heketi-storage-1-jqk63", 
        "heketi-cli", 
        "-s", 
        "http://localhost:8080", 
        "--user", 
        "admin", 
        "--secret", 
        "jkmhYsF09Fv+/HcyE4OFkCA/DYSezwFbFJ57HiB0wmY=", 
        "setup-openshift-heketi-storage", 
        "--listfile", 
        "/tmp/heketi-storage.json"
    ], 
    "delta": "0:00:09.311645", 
    "end": "2017-09-20 15:50:27.515474", 
    "failed": true, 
    "rc": 255, 
    "start": "2017-09-20 15:50:18.203829"
}

STDERR:

Error: Unable to execute command on glusterfs-storage-ndd17:   /usr/sbin/modprobe failed: 1
  thin: Required device-mapper target(s) not detected in your kernel.
  Run `lvcreate --help' for more information.
command terminated with exit code 255

Expected results:
CNS is deployed successfully.


Additional info:
This issue has been reported in the upstream as well:
https://github.com/openshift/openshift-ansible/issues/5108
https://github.com/gluster/gluster-kubernetes/issues/19

The workaround there (run modprobe dm_thin_pool on each node) works for me too.