NFS

首先,安装好一个NFS Server(参考https://pshizhsysu.gitbooks.io/linux/chang-yong-ruan-jian-an-zhuang-pian/nfs.html)。

假设上面安装的NFS Server export的目录为/nfs,接着我们在/nfs下创建一个子目录/dir1,并且在子目录下创建一个文件hello.txt

$ pwd
/nfs/dir1

$ ls
hello.txt

然后我们在k8s集群中创建一个PV与PVC,yaml文件如下(这里我们把回收策略设置为了Recycle):

apiVersion: v1
kind: PersistentVolume
metadata:
  name: nfs-pv1
spec:
  storageClassName: nfs
  accessModes:
  - ReadWriteMany
  capacity:
    storage: 1Gi
  persistentVolumeReclaimPolicy: Recycle
  nfs:
    server: 192.168.2.101
    path: /nfs/dir1
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: nfs-pvc1
spec:
  resources:
    requests:
      storage: 1Gi
  accessModes:
    - ReadWriteMany
  storageClassName: nfs

创建好之后,我们查看结果,发现它们已经绑定好了

$ kubectl get pv
NAME      CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM              STORAGECLASS   REASON   AGE
nfs-pv1   1Gi        RWX            Recycle           Bound    default/nfs-pvc1   nfs                     6s

但是,此时NFS并没有Mount到k8s的节点上(即在k8s的节点上执行df -hT | grep nfs的结果为空)。

接着,我们创建如下的一个Pod

apiVersion: v1
kind: Pod
metadata:
  name: tomcat
spec:
  containers:
    - image: tomcat:8
      name: tomcat
      volumeMounts:
        - name: volume1
          mountPath: /container
  volumes:
    - name: volume1
      persistentVolumeClaim:
        claimName: nfs-pvc1

创建好Pod后,我们查看Pod所在的节点上已经挂载上了NFS目录

$ kubectl get pod -o wide 
NAME     READY   STATUS    RESTARTS   AGE   IP               NODE     NOMINATED NODE   READINESS GATES
tomcat   1/1     Running   0          4s    172.26.220.109   peng04   <none>           <none>

$ df -hT | grep nfs
192.168.2.101:/nfs/dir1 nfs4       50G  7.1G   43G  15% /var/lib/kubelet/pods/96df027e-42f6-429e-b1c2-a81089caaf4a/volumes/kubernetes.io~nfs/nfs-pv1

接着,我们在Pod里面的/container目录下,可以看到NFS上的hello.txt文件

$ kubectl exec tomcat -- ls /container
hello.txt

接着,我们删除这个Pod,发现该节点上NFS的挂载就消失了。

接着,我们再删除PVC,我们会发现PV的状态先是变成了Released,然后马上就变成了Availabe;同时,我们也发现,NFS server的/nfs/dir1/目录下的内容被清空了

$ kubectl delete pvc nfs-pvc1

$ kubectl get pv 
NAME      CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS     CLAIM              STORAGECLASS   REASON   AGE
nfs-pv1   1Gi        RWX            Recycle          Released   default/nfs-pvc1   nfs                     5m6s

$ kubectl get pv
NAME      CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS      CLAIM   STORAGECLASS   REASON   AGE
nfs-pv1   1Gi        RWX            Recycle          Available           nfs                     5m9s

这是因为我们把PV的回收策略设置为了Recycle

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