Description of problem:
In containerzied OpenShift cluster, rbd volumes could not be dynamically provisioned.  PVC events logged failure reasion "rbd: create volume failed, err: executable file not found in $PATH"

Version-Release number of selected component (if applicable):
openshift v3.4.0.39
kubernetes v1.4.0+776c994
etcd 3.1.0-rc.0

How reproducible:
Always

Steps to Reproduce:
1. Setup containerized OpenShift cluster, setup ceph rbd storage server
2. Create a StorageClass for Ceph RBD provisioner
apiVersion: storage.k8s.io/v1beta1
kind: StorageClass
metadata:
  creationTimestamp: 2017-01-09T06:54:58Z
  name: cephrbdprovisioner
  resourceVersion: "8131"
  selfLink: /apis/storage.k8s.io/v1beta1/storageclasses/cephrbdprovisioner
  uid: 892a27c2-d638-11e6-800d-0eb7d2142d46
parameters:
  adminId: admin
  adminSecretName: cephrbd-secret
  adminSecretNamespace: default
  monitors: xxx:6789
  pool: rbd
  userId: admin
  userSecretName: cephrbd-user-secret
provisioner: kubernetes.io/rbd

3. Create a PVC to dynamically provision a PV
{
   "kind": "PersistentVolumeClaim",
   "apiVersion": "v1",
   "metadata": {
     "name": "rbdc",
     "annotations": {
     "volume.beta.kubernetes.io/storage-class": "cephrbdprovisioner"
     }
   },
   "spec": {
     "accessModes": [
       "ReadWriteOnce"
     ],
     "resources": {
       "requests": {
         "storage": "5Gi"
       }
     }
   }
}


Actual results:
After step 3: PVC is Pending, PV could not be provisioned.
 oc describe pvc rbdc
Name:		rbdc
Namespace:	jhou1
StorageClass:	cephrbdprovisioner
Status:		Pending
Volume:		
Labels:		<none>
Capacity:	
Access Modes:	
Events:
  FirstSeen	LastSeen	Count	From				SubobjectPath	Type		Reason			Message
  ---------	--------	-----	----				-------------	--------	------			-------
  18s		5s		2	{persistentvolume-controller }			Warning		ProvisioningFailed	Failed to provision volume with StorageClass "cephrbdprovisioner": rbd: create volume failed, err: executable file not found in $PATH


Expected results:
Should provision successfully.

Additional info: