Automatic merge from submit-queue
Implement CanMount() for gfsMounter for linux
**What this PR does / why we need it**:
To implement CanMount() check for glusterfs. If mount binaries are not present on the underlying node, the mount will not proceed and return an error message stating so.
Related to issue : https://github.com/kubernetes/kubernetes/issues/36098
Related to similar change for NFS :
https://github.com/kubernetes/kubernetes/pull/36280
**Release note**:
`Check binaries for GlusterFS on the underlying node before doing mount`
Sample output from testing in GCE/GCI:
rkouj@rkouj0:~/go/src/k8s.io/kubernetes$ kubectl describe pods
Name: glusterfs
Namespace: default
Node: e2e-test-rkouj-minion-group-kjq3/10.240.0.3
Start Time: Fri, 11 Nov 2016 17:22:04 -0800
Labels: <none>
Status: Pending
IP:
Controllers: <none>
Containers:
glusterfs:
Container ID:
Image: gcr.io/google_containers/busybox
Image ID:
Port:
QoS Tier:
cpu: Burstable
memory: BestEffort
Requests:
cpu: 100m
State: Waiting
Reason: ContainerCreating
Ready: False
Restart Count: 0
Environment Variables:
Conditions:
Type Status
Initialized True
Ready False
PodScheduled True
Volumes:
glusterfs:
Type: Glusterfs (a Glusterfs mount on the host that shares a pod's lifetime)
EndpointsName: glusterfs-cluster
Path: kube_vol
ReadOnly: true
default-token-2zcao:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-2zcao
Events:
FirstSeen LastSeen Count From SubobjectPath Type Reason Message
--------- -------- ----- ---- ------------- -------- ------ -------
8s 8s 1 {default-scheduler } Normal Scheduled Successfully assigned glusterfs to e2e-test-rkouj-minion-group-kjq3
7s 4s 4 {kubelet e2e-test-rkouj-minion-group-kjq3} Warning FailedMount Unable to mount volume kubernetes.io/glusterfs/6bb04587-a876-11e6-a712-42010af00002-glusterfs (spec.Name: glusterfs) on pod glusterfs (UID: 6bb04587-a876-11e6-a712-42010af00002). Verify that your node machine has the required components before attempting to mount this volume type. Required binary /sbin/mount.glusterfs is missing
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