<p>We ran into an issue with our GKE volume usage.</p>
<p>Starting from tonight our deployments couldn't access our main document storage disk anymore, the logs looked something like this:</p>
<pre><code>...
    /go/src/github.com/def/abc/backend/formulare/formulare_generate_http.go:62 +0x55
    github.com/def/abc/backend/formulare.CreateDirsIfNeeded(0xc000b9b1d0, 0x2e, 0x0, 0x0)
    /usr/local/go/src/os/path.go:20 +0x39
    os.MkdirAll(0xc000b9b1d0, 0x25, 0xc0000001ff, 0x25, 0xc000e75b18)
    /usr/local/go/src/os/stat.go:13 +0x4d
    os.Stat(0xc000b9b1d0, 0x25, 0xc000b9b1d0, 0x0, 0xc000b9b1d0, 0x25)
    /usr/local/go/src/os/stat_unix.go:31 +0x77
    os.statNolog(0xc000b9b1d0, 0x25, 0xc000171ac8, 0x2, 0x2, 0xc000b9b1d0)
    /usr/local/go/src/os/file_posix.go:245
    os.ignoringEINTR(...)
    /usr/local/go/src/os/stat_unix.go:32
    os.statNolog.func1(...)
    /usr/local/go/src/syscall/syscall_linux_amd64.go:66
    syscall.Stat(...)
    /usr/local/go/src/syscall/zsyscall_linux_amd64.go:1440 +0xd2
    syscall.fstatat(0xffffffffffffff9c, 0xc000b9b1d0, 0x25, 0xc001a90378, 0x0, 0xc000171ac0, 0x4f064b)
    /usr/local/go/src/syscall/asm_linux_amd64.s:43 +0x5
    syscall.Syscall6(0x106, 0xffffffffffffff9c, 0xc000b9b200, 0xc001a90378, 0x0, 0x0, 0x0, 0xc000ba4400, 0x0, 0xc000171a08)
    goroutine 808214 [syscall, 534 minutes]:
</code></pre>
<p>Upon recreating the pv/pvc and nfs server on gke the pv/pvc were successfully bound, but the nfs service didn't even startup anymore, because it couldn't bind the disk:</p>
<pre><code>      Warning  FailedMount  95s (x7 over 15m)  kubelet          
  Unable to attach or mount volumes: unmounted volumes=[document-storage-claim default-token-sbxxl], unattached volumes=[document-storage-claim default-token-sbxxl]: timed out waiting for the condition
</code></pre>
<p>Strangely the default google service account token volume couldn't be mounted either.</p>
<p>Could this be a google problem? Do I need to change my nfs-server configuration?</p>
<p>Here are my k8s definitions:</p>
<pre><code>kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: document-storage-claim
  namespace: default
spec:
  accessModes:
    - ReadWriteOnce
  storageClassName: standard
  volumeName: document-storage
  resources:
    requests:
      storage: 250Gi

--- 

apiVersion: v1
kind: PersistentVolume
metadata:
  name: document-storage
  namespace: default
spec:
  storageClassName: standard
  capacity:
    storage: 250Gi
  accessModes:
    - ReadWriteOnce
  persistentVolumeReclaimPolicy: Retain
  gcePersistentDisk:
    pdName: document-storage-clone
    fsType: ext4

--- 

apiVersion: v1
kind: ReplicationController
metadata:
  name: document-storage-nfs-server
spec:
  replicas: 1
  selector:
    role: nfs-server
  template:
    metadata:
      labels:
        role: nfs-server
    spec:
      securityContext:
        fsGroup: 1000
      containers:
        - name: nfs-server
          image: k8s.gcr.io/volume-nfs:0.8
          ports:
            - name: nfs
              containerPort: 2049
            - name: mountd
              containerPort: 20048
            - name: rpcbind
              containerPort: 111
          securityContext:
            privileged: true
          volumeMounts:
            - mountPath: /exports
              name: document-storage-claim
      volumes:
        - name: document-storage-claim
          persistentVolumeClaim:
            claimName: document-storage-claim
</code></pre>

<p>It seems that Google introduced a GKE update in the night to 2020-04-20. Somehow this update also affected previous versions (in our case 1.18.16-gke.502).</p>
<p>We fixed the problem by upgrading to 1.19.8-gke.1600.</p>
<p>Other possible workarounds would be to:</p>
<ul>
<li>Create a clone of the problematic volume and remount it into your deployment.</li>
<li>Redeploy your node pool.</li>
</ul>
