k8s-PV、PVC(7)

1、什么是PV、PVC

PV(PersistentVolume):持久化卷

PVC(PersistentVolumeClaim):持久化声明

为何有了Volumes,还要引进PV、PVC?因为Volumes的类型有很多,每次切换不同的类型如hotsPath,第三方的云存储,都需要手动改动yaml的对应的类型,且每种类型的写法声明方式都不同,导致不灵活不好维护。为了解决该问题,通过PV来抽象了各种类型,具体实现由具体存储方去实现,客户端只需要通过PVC声明,指定对应的storageClassName,即可匹配符合的第三方PV,无需关心其实现细节,且无需做任何修改。

2、通过mysql来实操PV、PVC

一、创建PV,类型为hostPath:

apiVersion: v1
kind: PersistentVolume
metadata:
  name: mysql-pv-volume
  labels:
    type: local
spec:
  storageClassName: manual  #与请求的PVC对应
  capacity:
    storage: 1Gi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: "/var/lib/mysql"
kubectl apply -f mysql-pv.yaml

查看状态:

kubectl get pv

k8s-PV、PVC(7)

二、创建PVC

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: mysql-pv-claim
spec:
  storageClassName: manual #与PV的对应
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi
kubectl apply -f mysql-pvc.yaml

查看状态:

k8s-PV、PVC(7)

由STATUS为Bound可知已经与上面的PV绑定。

三、创建Mysql Deployment

apiVersion: apps/v1
kind: Deployment
metadata:
  name: mysql-pv-deploy
spec:
  replicas: 1
  selector:
    matchLabels:
      name: k8s-mysql
  template:
    metadata:
      labels:
        name: k8s-mysql
    spec:
      containers:
      - name: mysql
        image: registry.cn-shenzhen.aliyuncs.com/luozhilian/k8s:mysql5.6
        env:
        - name: MYSQL_ROOT_PASSWORD
          value: password
        imagePullPolicy: IfNotPresent
        ports:
        - containerPort: 3306
          name: mysql
        volumeMounts:
        - mountPath: /var/lib/mysql
          name: mysql-persistent-storage
      volumes:
      - name: mysql-persistent-storage
        persistentVolumeClaim:  # 此处使用pvc声明
          claimName: mysql-pv-claim
---
kind: Service
apiVersion: v1
metadata:
  name: k8s-mysql-service
spec:
  type: NodePort
  ports:
  - port: 5000
    targetPort: 3306
    nodePort: 32000
  selector:
    name: k8s-mysql

kubectl apply -f mysql-deploy.yaml
kubectl get pod,svc -o wide

k8s-PV、PVC(7)

用Navicat连接mysql,创建一个测试数据库:

k8s-PV、PVC(7)

查看node1主机的挂载的路径数据 /var/lib/mysql/:

k8s-PV、PVC(7)

删除mysql 对应的pod,让k8s重新创建pod:

kubectl delete pod mysql-pv-deploy-d7b7fd5b5-m6n44

再登录连接mysql,查看创建的数据库是否还存在:

k8s-PV、PVC(7)

如上图,依然存在

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