Description of problem:
When running OSE 3.2 containerize on a Rhel Atomic Host, pods created on the node cannot mount remote ceph RBDs.  The reason is that the docker run in atomic-openshift-node.service bind mounts /sys:/sys as read-only.  It should instead be read write.


Version-Release number of selected component (if applicable):
2 VM OSE 3.2 Cluster
Master: Rhel 7.2 Server
Node:   RHEL AH 7.2
Ceph:   AIO Containerized Demo hosted on Master


How reproducible:
Very.  Problem occurs because of a default configuration for atomic-openshift-node.service


Steps to Reproduce:
1. Install OSE 3.2 using atomic-openshift-installer. Select rpm for master, containerize for node.

2. deploy ceph demo: 
`docker run --net=host -v /etc/ceph:/etc/ceph -v /var/lib/ceph:/var/lib/ceph   -e MON_IP=192.168.124.240 -e CEPH_NETWORK=192.168.124.0/24 -e CEPH_PUBLIC_NETWORK=192.168.124.0/24  ceph/demo`

3. Create and deploy ceph secret, persistent volume, and claim specs per https://docs.openshift.org/latest/install_config/persistent_storage/persistent_storage_ceph_rbd.html.

Pod template used:
apiVersion: v1
kind: Pod
metadata:
  generateName: ceph-nginx-pvc-
  labels:
    vol: ceph 
spec:
  containers:
   - name: ceph-pvc
     image: fedora/nginx 
     volumeMounts:
       - name: cephvol
         mountPath: /mnt/import
  securityContext:
    privileged: true
  volumes:
    - name: cephvol 
      persistentVolumeClaim:
        claimName: ceph-claim

4. oc describe pod to view relevant errors


Actual results:

journal -eu atomic-openshift-node output:
Aug 17 10:12:51 node.ae atomic-openshift-node[3448]: E0817 10:12:51.001795    3499 pod_workers.go:138] Error syncing pod a22f1231-6488-11e6-9284-5254007c2254, skipping: rbd: map failed exit status 30 2016-08-17 10:12:50.982834 7fc7100987c
Aug 17 10:12:51 node.ae atomic-openshift-node[3448]: rbd: add failed: (30) Read-only file system
Aug 17 10:13:02 node.ae atomic-openshift-node[3448]: I0817 10:13:02.966649    3499 rbd.go:89] ceph secret info: key/AQBSLK5XeNKqBxAAdYFblXFkebX2KVVEo7ESjw==
Aug 17 10:13:03 node.ae atomic-openshift-node[3448]: I0817 10:13:03.970063    3499 rbd_util.go:229] rbd: map mon 192.168.124.240:6789
Aug 17 10:13:04 node.ae atomic-openshift-node[3448]: I0817 10:13:04.011021    3499 rbd_util.go:240] rbd: map error exit status 30 2016-08-17 10:13:03.978876 7f5ab10b67c0 -1 did not load config file, using default settings.
Aug 17 10:13:04 node.ae atomic-openshift-node[3448]: rbd: add failed: (30) Read-only file system
Aug 17 10:13:04 node.ae atomic-openshift-node[3448]: E0817 10:13:04.011093    3499 disk_manager.go:56] failed to attach disk
Aug 17 10:13:04 node.ae atomic-openshift-node[3448]: E0817 10:13:04.011103    3499 rbd.go:208] rbd: failed to setup
Aug 17 10:13:04 node.ae atomic-openshift-node[3448]: E0817 10:13:04.011170    3499 kubelet.go:1796] Unable to mount volumes for pod "ceph-nginx-pvc-0gr12_default(a22f1231-6488-11e6-9284-5254007c2254)": rbd: map failed exit status 30 2016-
Aug 17 10:13:04 node.ae atomic-openshift-node[3448]: rbd: add failed: (30) Read-only file system
Aug 17 10:13:04 node.ae atomic-openshift-node[3448]: ; skipping pod



Expected results:
successfully attach rbd to pod via pvc

Additional Info:

I was able to create the pod after modifying /etc/systemd/system/atomic-openshift-node.service.  Changing ExecStart=/usr/bin/docker run --name atomic-openshift-node --rm --privileged ....... -v /sys:/sys:ro.... to -v /sys:/sys:rw    After that, systemctl daemon-reload && systemctl restart atomic-openshift-node.