完成下列实验需搭建k8s集群环境如下：

* master节点IP：192.168.45.129
* node01节点IP：192.168.45.141
* node02节点IP：192.168.45.142

注：这里实验环境提前搭建好了如想搭建k8s集群前参考博文：kubeadm部署kubernetes(k8s)集群

1）搭建NFS共享存储
本次案例直接在master节点上创建NFS存储！

[root@master ~]# yum -y install nfs-utils rpcbind
[root@master ~]# vim /etc/exports
/nfsdata *(rw,sync,no_root_squash)
[root@master ~]# systemctl start nfs-server
[root@master ~]# systemctl start rpcbind
[root@master ~]# showmount -e
Export list for master:
/nfsdata *

2）创建PV资源对象

[root@master ~]# vim mysql-pv.yaml    //编写pv的yaml文件
apiVersion: v1
kind: PersistentVolume
metadata:
  name: mysql-pv
spec:
  capacity:
    storage: 1Gi
  accessModes:
    - ReadWriteOnce                   //访问模式定义为只能以读写的方式挂载到单个节点
  persistentVolumeReclaimPolicy: Retain                  //注意指定的回收策略为手动回收
  storageClassName: nfs
  nfs:
    path: /nfsdata/mysql-pv
    server: 192.168.45.129

[root@master ~]# kubectl apply -f mysql-pv.yaml    //执行yaml文件
[root@master ~]# kubectl get pv
NAME       CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS      CLAIM   STORAGECLASS   REASON   AGE
mysql-pv   1Gi        RWO            Retain           Available           nfs                     7s

[root@master ~]# mkdir -p /nfsdata/mysql-pv 

3）创建PVC资源对象

[root@master ~]# vim mysql-pvc.yaml   //编写pvcyaml文件
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: mysql-pvc
spec:
  accessModes:
  - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi
  storageClassName: nfs  //这里指定关联的PV名称

[root@master ~]# kubectl apply -f mysql-pvc.yaml  //执行yaml文件
[root@master ~]# kubectl  get  pv,pvc    
//查看pv和pvc已经关联上了
//PV和PVC的状态类应该全是Bound。
NAME                        CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM               STORAGECLASS   REASON   AGE
persistentvolume/mysql-pv   1Gi        RWO            Retain           Bound    default/mysql-pvc   nfs                     108s

NAME                              STATUS   VOLUME     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
persistentvolumeclaim/mysql-pvc   Bound    mysql-pv   1Gi        RWO            nfs            21s

4）创建pod资源

[root@master ~]# vim mysql-pod.yaml  //编写pod的yaml文件
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: mysql-pod
spec:
  selector:                     //设置给予等值的标签选择器
    matchLabels:
      app: mysql
  template:
    metadata:
      labels:
        app: mysql
    spec:
      containers:
      - image: mysql:5.6
        name: mysql
        env:                      //设置环境变量，数据库root用户的密码
        - name: MYSQL_ROOT_PASSWORD
          value: 123.com
        volumeMounts:
        - name: mysql-storage
          mountPath: /var/lib/mysql               //这个目录是数据库存放数据的目录（指定的是容器中的目录）
      volumes:
      - name: mysql-storage
        persistentVolumeClaim:
          claimName: mysql-pvc        //指定pvc的名称

[root@master ~]# kubectl apply -f mysql-pod.yaml 
[root@master ~]# kubectl get pod
NAME                         READY   STATUS    RESTARTS   AGE
mysql-pod-6cc889468b-g8cw6   1/1     Running   0          39s

5）测试数据持久化效果

[root@master ~]# kubectl  get  pod -o wide  //查看容器的ID
NAME                         READY   STATUS    RESTARTS   AGE     IP           NODE     NOMINATED NODE   READINESS GATES
mysql-pod-6cc889468b-g8cw6   1/1     Running   0          3m54s   10.244.2.2   node01   <none>           <none>

[root@master ~]# kubectl  exec  -it mysql-pod-6cc889468b-g8cw6  -- mysql -u root -p123.com
//直接登录运行mysql数据库的pod中的mysql
//插入数据进行测试

mysql>  create database bjq;
Query OK, 1 row affected (0.00 sec)

mysql> use bjq;
Database changed
mysql> create table my_id( id int(4) );
Query OK, 0 rows affected (0.03 sec)

mysql>  insert my_id values (9527);
Query OK, 1 row affected (0.01 sec)

mysql> select * from my_id;
+------+
| id   |
+------+
| 9527 |
+------+
1 row in set (0.00 sec)

[root@master ~]# ls /nfsdata/mysql-pv/   //查看pod对应的NFS的目录，确实有了数据
auto.cnf  bjq  ibdata1  ib_logfile0  ib_logfile1  mysql  performance_schema

6）模拟MySQL容器所在的节点宕机，验证数据是否会丢失

[root@master ~]# kubectl  get  pod -o wide
//查看到pod是运行在node01节点上的
//模拟node01宕机，步骤省略，关机、挂起都可以！
NAME                         READY   STATUS    RESTARTS   AGE     IP           NODE     NOMINATED NODE   READINESS GATES
mysql-pod-6cc889468b-g8cw6   1/1     Running   0          8m48s   10.244.2.2   node01   <none>           <none>

[root@node02 ~]# systemctl restart  kubelet.service 
//重启node02的kubelet服务
//接下来耐心等待pod的转移，可能需要差不多5分钟请耐性等待

[root@master ~]# kubectl  get  pod -o wide  //可以看到pod已经运行在node02上
NAME                         READY   STATUS        RESTARTS   AGE   IP           NODE     NOMINATED NODE   READINESS GATES
mysql-pod-6cc889468b-25ltd   1/1     Running       0          65s   10.244.1.2   node02   <none>           <none>
mysql-pod-6cc889468b-g8cw6   1/1     Terminating   0          19m   10.244.2.2   node01   <none>           <none>

[root@master ~]# kubectl exec  -it  mysql-pod-6cc889468b-25ltd -- mysql -u root -p123.com
//再次登录到pod中运行的mysql（注意：pod的名称）
//查看数据是否还存在，发现数据依然存在
mysql> select * from bjq.my_id;   
+------+
| id   |
+------+
| 9527 |
+------+
1 row in set (0.01 sec)

K8s之MySQL实现数据持久化