NFS volume sharing issue between wordpress pod and mysql pod - kubernetes

Question

This repository kubernetes-wordpress-with-nfs-volume-on-gke is trying to implement a wordpress application that shares an NFS volume between mySQL and wordpress. The idea behind sharing a NFS volume between pods is to implement in the next step a StatefulSet for mySQL. This StatefulSet application will need to share the database (the volume of the database) between all the pods of mySQL so that a multi node database is created that ensures the requested high performance.
To do that, there is an example janakiramm/wp-statefulset. This example is using etcd. So why not using nfs in stead of etcd?
The commands to run to create this kubernetes wordpress application that shared the NFS volume between MySQL and wordpress are:
kubectl create -f 01-pv-gce.yml
kubectl create -f 02-dep-nfs.yml
kubectl create -f 03-srv-nfs.yml
kubectl get services # you have to update the file 04-pv-pvc with the new IP address of the service
kubectl create -f 04-pv-pvc.yml
kubectl create -f 05-mysql.yml
kubectl create -f 06-wordpress.yml
This implementation did not succeed. The wordpress pod is not starting:
$ kubectl get pods
NAME READY STATUS RESTARTS AGE
nfs-server-2899972627-jgjx0 1/1 Running 0 4m
wp01-mysql-1941769936-m9jjd 1/1 Running 0 3m
wp01-wordpress-2362719074-bv53t 0/1 CrashLoopBackOff 4 2m
It seems to be that there is a problem to access to NFS volume as described below:
$ kubectl describe pods wp01-wordpress-2362719074-bv53t
Name: wp01-wordpress-2362719074-bv53t
Namespace: default
Node: gke-mappedinn-cluster-default-pool-6264f94a-z0sh/10.240.0.4
Start Time: Thu, 04 May 2017 05:59:12 +0400
Labels: app=wp01
pod-template-hash=2362719074
tier=frontend
Annotations: kubernetes.io/created-by={"kind":"SerializedReference","apiVersion":"v1","reference":{"kind":"ReplicaSet","namespace":"default","name":"wp01-wordpress-2362719074","uid":"44b91da0-306d-11e7-a0d1-42010a...
kubernetes.io/limit-ranger=LimitRanger plugin set: cpu request for container wordpress
Status: Running
IP: 10.244.0.4
Controllers: ReplicaSet/wp01-wordpress-2362719074
Containers:
wordpress:
Container ID: docker://658c7392c1b7a5033fe1a1b456a9653161003ee2878a4f02c6a12abb49241d47
Image: wordpress:4.6.1-apache
Image ID: docker://sha256:ee397259d4e59c65e2c1c5979a3634eb3ab106bba389acea8b21862053359134
Port: 80/TCP
State: Waiting
Reason: CrashLoopBackOff
Last State: Terminated
Reason: Error
Exit Code: 1
Started: Thu, 04 May 2017 06:03:16 +0400
Finished: Thu, 04 May 2017 06:03:16 +0400
Ready: False
Restart Count: 5
Requests:
cpu: 100m
Environment:
WORDPRESS_DB_HOST: wp01-mysql
WORDPRESS_DB_PASSWORD: <set to the key 'password' in secret 'wp01-pwd-wordpress'> Optional: false
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from default-token-k650h (ro)
/var/www/html from wordpress-persistent-storage (rw)
Conditions:
Type Status
Initialized True
Ready False
PodScheduled True
Volumes:
wordpress-persistent-storage:
Type: PersistentVolumeClaim (a reference to a PersistentVolumeClaim in the same namespace)
ClaimName: wp01-pvc-data
ReadOnly: false
default-token-k650h:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-k650h
Optional: false
QoS Class: Burstable
Node-Selectors: <none>
Tolerations: <none>
Events:
FirstSeen LastSeen Count From SubObjectPath Type Reason Message
--------- -------- ----- ---- ------------- -------- ------ -------
5m 5m 1 default-scheduler Normal Scheduled Successfully assigned wp01-wordpress-2362719074-bv53t to gke-mappedinn-cluster-default-pool-6264f94a-z0sh
4m 4m 1 kubelet, gke-mappedinn-cluster-default-pool-6264f94a-z0sh spec.containers{wordpress} Normal Pulling pulling image "wordpress:4.6.1-apache"
4m 4m 1 kubelet, gke-mappedinn-cluster-default-pool-6264f94a-z0sh spec.containers{wordpress} Normal Pulled Successfully pulled image "wordpress:4.6.1-apache"
4m 4m 1 kubelet, gke-mappedinn-cluster-default-pool-6264f94a-z0sh spec.containers{wordpress} Normal Created Created container with docker id 8647e997d6f4; Security:[seccomp=unconfined]
4m 4m 1 kubelet, gke-mappedinn-cluster-default-pool-6264f94a-z0sh spec.containers{wordpress} Normal Started Started container with docker id 8647e997d6f4
4m 4m 1 kubelet, gke-mappedinn-cluster-default-pool-6264f94a-z0sh spec.containers{wordpress} Normal Created Created container with docker id 37f4f0fd392d; Security:[seccomp=unconfined]
4m 4m 1 kubelet, gke-mappedinn-cluster-default-pool-6264f94a-z0sh spec.containers{wordpress} Normal Started Started container with docker id 37f4f0fd392d
4m 4m 1 kubelet, gke-mappedinn-cluster-default-pool-6264f94a-z0sh Warning FailedSync Error syncing pod, skipping: failed to "StartContainer" for "wordpress" with CrashLoopBackOff: "Back-off 10s restarting failed container=wordpress pod=wp01-wordpress-2362719074-bv53t_default(44ba1226-306d-11e7-a0d1-42010a8e0084)"
3m 3m 1 kubelet, gke-mappedinn-cluster-default-pool-6264f94a-z0sh spec.containers{wordpress} Normal Created Created container with docker id b78a661388a2; Security:[seccomp=unconfined]
3m 3m 1 kubelet, gke-mappedinn-cluster-default-pool-6264f94a-z0sh spec.containers{wordpress} Normal Started Started container with docker id b78a661388a2
3m 3m 2 kubelet, gke-mappedinn-cluster-default-pool-6264f94a-z0sh Warning FailedSync Error syncing pod, skipping: failed to "StartContainer" for "wordpress" with CrashLoopBackOff: "Back-off 20s restarting failed container=wordpress pod=wp01-wordpress-2362719074-bv53t_default(44ba1226-306d-11e7-a0d1-42010a8e0084)"
3m 3m 1 kubelet, gke-mappedinn-cluster-default-pool-6264f94a-z0sh spec.containers{wordpress} Normal Created Created container with docker id 2b6384407678; Security:[seccomp=unconfined]
3m 3m 1 kubelet, gke-mappedinn-cluster-default-pool-6264f94a-z0sh spec.containers{wordpress} Normal Started Started container with docker id 2b6384407678
3m 2m 4 kubelet, gke-mappedinn-cluster-default-pool-6264f94a-z0sh Warning FailedSync Error syncing pod, skipping: failed to "StartContainer" for "wordpress" with CrashLoopBackOff: "Back-off 40s restarting failed container=wordpress pod=wp01-wordpress-2362719074-bv53t_default(44ba1226-306d-11e7-a0d1-42010a8e0084)"
2m 2m 1 kubelet, gke-mappedinn-cluster-default-pool-6264f94a-z0sh spec.containers{wordpress} Normal Created Created container with docker id 930a3410b213; Security:[seccomp=unconfined]
2m 2m 1 kubelet, gke-mappedinn-cluster-default-pool-6264f94a-z0sh spec.containers{wordpress} Normal Started Started container with docker id 930a3410b213
2m 1m 7 kubelet, gke-mappedinn-cluster-default-pool-6264f94a-z0sh Warning FailedSync Error syncing pod, skipping: failed to "StartContainer" for "wordpress" with CrashLoopBackOff: "Back-off 1m20s restarting failed container=wordpress pod=wp01-wordpress-2362719074-bv53t_default(44ba1226-306d-11e7-a0d1-42010a8e0084)"
4m 1m 5 kubelet, gke-mappedinn-cluster-default-pool-6264f94a-z0sh spec.containers{wordpress} Normal Pulled Container image "wordpress:4.6.1-apache" already present on machine
1m 1m 1 kubelet, gke-mappedinn-cluster-default-pool-6264f94a-z0sh spec.containers{wordpress} Normal Created Created container with docker id 658c7392c1b7; Security:[seccomp=unconfined]
1m 1m 1 kubelet, gke-mappedinn-cluster-default-pool-6264f94a-z0sh spec.containers{wordpress} Normal Started Started container with docker id 658c7392c1b7
4m 10s 19 kubelet, gke-mappedinn-cluster-default-pool-6264f94a-z0sh spec.containers{wordpress} Warning BackOff Back-off restarting failed docker container
1m 10s 5 kubelet, gke-mappedinn-cluster-default-pool-6264f94a-z0sh
Could you please help on that issue?