<p>I install kubernetes on ubuntu on baremetal. I deploy 1 master and 3 worker.
and then deploy rook and every thing work fine.but when i want to deploy a wordpress on it ,it stuck in container creating and then i delete wordpress and now i got this error</p>

<blockquote>
  <p>Volume is already attached by pod
  default/wordpress-mysql-b78774f44-gvr58. Status Running</p>
</blockquote>

<pre><code>#kubectl describe pods wordpress-mysql-b78774f44-bjc2c

Events:
  Type     Reason       Age                    From               Message
  ----     ------       ----                   ----               -------
  Normal   Scheduled    3m21s                  default-scheduler  Successfully assigned default/wordpress-mysql-b78774f44-bjc2c to worker2
  Warning  FailedMount  2m57s (x6 over 3m16s)  kubelet, worker2   MountVolume.SetUp failed for volume "pvc-dcba7817-553b-11e9-a229-52540076d16c" : mount command failed, status: Failure, reason: Rook: Mount volume failed: failed to attach volume pvc-dcba7817-553b-11e9-a229-52540076d16c for pod default/wordpress-mysql-b78774f44-bjc2c. Volume is already attached by pod default/wordpress-mysql-b78774f44-gvr58. Status Running
  Normal   Pulling      2m26s                  kubelet, worker2   Pulling image "mysql:5.6"
  Normal   Pulled       110s                   kubelet, worker2   Successfully pulled image "mysql:5.6"
  Normal   Created      106s                   kubelet, worker2   Created container mysql
  Normal   Started      101s                   kubelet, worker2   Started container mysql

   for more information
# kubectl get pv
NAME                                       CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM                    STORAGECLASS      REASON   AGE
pvc-dcba7817-553b-11e9-a229-52540076d16c   20Gi       RWO            Delete           Bound    default/mysql-pv-claim   rook-ceph-block            13m
pvc-e9797517-553b-11e9-a229-52540076d16c   20Gi       RWO            Delete           Bound    default/wp-pv-claim      rook-ceph-block            13m
#kubectl get pvc
NAME             STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS      AGE
mysql-pv-claim   Bound    pvc-dcba7817-553b-11e9-a229-52540076d16c   20Gi       RWO            rook-ceph-block   15m
wp-pv-claim      Bound    pvc-e9797517-553b-11e9-a229-52540076d16c   20Gi       RWO            rook-ceph-block   14m

#kubectl get pods --all-namespaces
NAMESPACE          NAME                                  READY   STATUS      RESTARTS   AGE
default            wordpress-595685cc49-sdbfk            1/1     Running     6          9m58s
default            wordpress-mysql-b78774f44-bjc2c       1/1     Running     0          8m14s
kube-system        coredns-fb8b8dccf-plnt4               1/1     Running     0          46m
kube-system        coredns-fb8b8dccf-xrkql               1/1     Running     0          47m
kube-system        etcd-master                           1/1     Running     0          46m
kube-system        kube-apiserver-master                 1/1     Running     0          46m
kube-system        kube-controller-manager-master        1/1     Running     1          46m
kube-system        kube-flannel-ds-amd64-45bsf           1/1     Running     0          40m
kube-system        kube-flannel-ds-amd64-5nxfz           1/1     Running     0          40m
kube-system        kube-flannel-ds-amd64-pnln9           1/1     Running     0          40m
kube-system        kube-flannel-ds-amd64-sg4pv           1/1     Running     0          40m
kube-system        kube-proxy-2xsrn                      1/1     Running     0          47m
kube-system        kube-proxy-mll8b                      1/1     Running     0          42m
kube-system        kube-proxy-mv5dw                      1/1     Running     0          42m
kube-system        kube-proxy-v2jww                      1/1     Running     0          42m
kube-system        kube-scheduler-master                 1/1     Running     0          46m
rook-ceph-system   rook-ceph-agent-8pbtv                 1/1     Running     0          26m
rook-ceph-system   rook-ceph-agent-hsn27                 1/1     Running     0          26m
rook-ceph-system   rook-ceph-agent-qjqqx                 1/1     Running     0          26m
rook-ceph-system   rook-ceph-operator-d97564799-9szvr    1/1     Running     0          27m
rook-ceph-system   rook-discover-26g84                   1/1     Running     0          26m
rook-ceph-system   rook-discover-hf7lc                   1/1     Running     0          26m
rook-ceph-system   rook-discover-jc72g                   1/1     Running     0          26m
rook-ceph          rook-ceph-mgr-a-68cb58b456-9rrj7      1/1     Running     0          21m
rook-ceph          rook-ceph-mon-a-6469b4c68f-cq6mj      1/1     Running     0          23m
rook-ceph          rook-ceph-mon-b-d59cfd758-2d2zt       1/1     Running     0          22m
rook-ceph          rook-ceph-mon-c-79664b789-wl4t4       1/1     Running     0          21m
rook-ceph          rook-ceph-osd-0-8778dbbc-d84mh        1/1     Running     0          19m
rook-ceph          rook-ceph-osd-1-84974b86f6-z5c6c      1/1     Running     0          19m
rook-ceph          rook-ceph-osd-2-84f9b78587-czx6d      1/1     Running     0          19m
rook-ceph          rook-ceph-osd-prepare-worker1-x4rqc   0/2     Completed   0          20m
rook-ceph          rook-ceph-osd-prepare-worker2-29jpg   0/2     Completed   0          20m
rook-ceph          rook-ceph-osd-prepare-worker3-rkp52   0/2     Completed   0          20m
</code></pre>

yasin lachini
<p>You are using a standard class storage for your PVC, and your policy will be <code>ReadWriteOnce</code>. This does not mean you can only connect your PVC to one pod, but only to one <em>node</em>.</p>
<blockquote>
<p><code>ReadWriteOnce</code> – the volume can be mounted as read-write by a single node</p>
<p><code>ReadWriteMany</code> – the volume can be mounted as read-write by many nodes</p>
</blockquote>
<p>Here, seems like you have 2 pods trying to mount this volume. This will be flakey unless you do one of two things:</p>
<ul>
<li><a href="https://kubernetes.io/docs/concepts/configuration/assign-pod-node/" rel="nofollow noreferrer">Schedule both pods on the same node</a><br></li>
<li>Use other <code>storageClasses</code> such as <a href="https://kubernetes.io/docs/concepts/storage/volumes/#nfs" rel="nofollow noreferrer">NFS</a> (FileSystem) to change policy to <code>ReadWriteMany</code></li>
<li>Downscale to 1 pod, so you don't have to share the volume</li>
</ul>
<p>Right now you have 2 pods trying to mount the same volume, <code>default/wordpress-mysql-b78774f44-gvr58</code> and <code>default/wordpress-mysql-b78774f44-bjc2c</code>.</p>
<p>You can also downscale to 1 pod, so you don't have to worry about any of the above altogether:</p>
<pre><code>kubectl scale deploy wordpress-mysql --replicas=1
</code></pre>
