kubernetes-Volume（k8s数据持久化）

• 1）emptyDir(pod删除卷被删除)

  点击查看代码

  [root@anyu967master1 volume]# more ./emptydir.yaml 
  apiVersion: v1
  kind: Pod
  metadata:
    name: pod-empty
  spec:
    containers:
    - name: container-empty
      image: nginx
      imagePullPolicy: IfNotPresent
      volumeMounts:
      - mountPath: /cache
        name: cache-volume
    volumes:
    - name: cache-volume
      emptyDir: {}
  [root@anyu967master1 volume]# kubectl get pods -o wide
  NAME        READY   STATUS    RESTARTS      AGE   IP               NODE           NOMINATED NODE   READINESS GATES
  demo-pod    1/1     Running   7 (21h ago)   13d   10.244.255.178   anyu967node2   <none>           <none>
  pod-empty   1/1     Running   0             69s   10.244.255.180   anyu967node2   <none>           <none>
  [root@anyu967master1 volume]# kubectl get pods pod-empty -o yaml |grep uid
    uid: cfcda1a8-4a8e-4141-9422-d6cacac21ac8
  [root@anyu967node2 ~]# tree /var/lib/kubelet/pods/cfcda1a8-4a8e-4141-9422-d6cacac21ac8
  /var/lib/kubelet/pods/cfcda1a8-4a8e-4141-9422-d6cacac21ac8
  ├── containers
  │   └── container-empty
  │       └── 59e15d9f
  ├── etc-hosts
  ├── plugins
  │   └── kubernetes.io~empty-dir
  │       ├── cache-volume
  │       │   └── ready
  │       └── wrapped_kube-api-access-wx7m6
  │           └── ready
  └── volumes
      ├── kubernetes.io~empty-dir
      │   └── cache-volume
      └── kubernetes.io~projected
          └── kube-api-access-wx7m6
              ├── ca.crt -> ..data/ca.crt
              ├── namespace -> ..data/namespace
              └── token -> ..data/token
  

• 2）hostPath(pod删除卷不会被删除)

  点击查看代码

  [root@anyu967master1 volume]# cat ./hostPath.yaml 
  apiVersion: v1
  kind: Pod
  metadata:
    name: test-hostpath
  spec:
    # nodeName: anyu967node2
    containers:
      - image: nginx
        imagePullPolicy: IfNotPresent
        name: test-nginx
        volumeMounts:
          - mountPath: /test-nginx
            name: test-volume
      - image: tomcat:8.5-jre8-alpine
        imagePullPolicy: IfNotPresent
        name: test-tomcat
        volumeMounts:
          - mountPath: /test-tomcat
            name: test-volume
    volumes:
      - name: test-volume
        hostPath:
          path: /home/xy/data1
          type: DirectoryOrCreate
  [root@anyu967master1 volume]# kubectl get pods -o wide
  NAME            READY   STATUS    RESTARTS      AGE   IP               NODE           NOMINATED NODE   READINESS GATES
  test-hostpath   2/2     Running   0             21s   10.244.255.186   anyu967node2   <none>           <none>
  [root@anyu967master1 xy]# kubectl exec -it test-hostpath -c test-nginx -- /bin/sh
  

• 3）nfs(network file system)

  点击查看代码

  [root@anyu967master1 volume]# yum install nfs-utils -y
  [root@anyu967master1 volume]# ll /home/xy/data/volumes
  [root@anyu967master1 volume]# more /etc/exports
  /home/xy/data/volumes 192.168.56.0/24(rw,no_root_squash)
  [root@anyu967master1 volume]# exportfs -arv
  exporting 192.168.56.0/24:/home/xy/data/volumes
  
  [root@anyu967master1 volume]# cat ./nfs.yaml 
  apiVersion: v1
  kind: Pod
  metadata:
    name: test-nfs-volume
  spec:
    containers:
    - name: test-nfs
      image: nginx
      imagePullPolicy: IfNotPresent
      ports:
      - containerPort: 80
        protocol: TCP
      volumeMounts:
      - name: nfs-volumes
        mountPath: /usr/share/nginx/html
    volumes:
    - name: nfs-volumes
      nfs:
        path: /home/xy/data/volumes
        server: 192.168.56.129
  
  [root@anyu967node1 xy]# mount 192.168.56.129:/home/xy/data/volumes /home/xy/nfs/
  

• 4）PV & PVC & StorageClass(持久化存储卷)

  访问模式：
  ReadWriteOnce(RWO), 卷可以被一个节点以读写方式挂载

  ReadOnlyMany(ROX), 卷可以被多个节点以只读方式挂载

  ReadWriteMany(RWX), 卷可以被多个节点以读写方式挂载

  点击查看代码

  [root@anyu967master1 volumes_pv]# exportfs -arv
  exporting 192.168.56.0/24:/home/xy/data/volumes_pv/v4
  exporting 192.168.56.0/24:/home/xy/data/volumes_pv/v3
  exporting 192.168.56.0/24:/home/xy/data/volumes_pv/v2
  exporting 192.168.56.0/24:/home/xy/data/volumes_pv/v1
  exporting 192.168.56.0/24:/home/xy/data/volumes
  
  [root@anyu967master1 volume]# kubectl get pv
  NAME   CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS      CLAIM   STORAGECLASS   REASON   AGE
  v1     1Gi        RWO            Retain           Available                                   18s
  v2     2Gi        RWX            Retain           Available                                   18s
  v3     3Gi        ROX            Retain           Available                                   18s
  v4     4Gi        RWO,RWX        Retain           Available                                   18s
  [root@anyu967master1 volume]# kubectl get pvc
  NAME     STATUS   VOLUME   CAPACITY   ACCESS MODES   STORAGECLASS   AGE
  my-pvc   Bound    v2       2Gi        RWX                           6s
  [root@anyu967master1 volume]# kubectl get pv
  NAME   CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS      CLAIM            STORAGECLASS   REASON   AGE
  v1     1Gi        RWO            Retain           Available                                            7m48s
  v2     2Gi        RWX            Retain           Bound       default/my-pvc                           7m48s
  v3     3Gi        ROX            Retain           Available                                            7m48s
  v4     4Gi        RWO,RWX        Retain           Available                                            7m48s
  [root@anyu967master1 volume]# kubectl get pods -o wide
  NAME       READY   STATUS    RESTARTS      AGE   IP               NODE           NOMINATED NODE   READINESS GATES
  pod-pvc    1/1     Running   0             14s   10.244.255.190   anyu967node2   <none>           <none>
  
  # StorageClass 创建PV的模板,动态供给PV
  [root@anyu967master1 volume]# kubectl get sa
  NAME              SECRETS   AGE
  default           0         18d
  nfs-provisioner   0         12s
  [root@anyu967master1 data]# kubectl create clusterrolebinding nfs-provisioner --clusterrole=cluster-admin --serviceaccount=default:nfs-provisioner
  clusterrolebinding.rbac.authorization.k8s.io/nfs-provisioner created
  [root@anyu967master1 volume]# kubectl apply -f nfsDeployment.yaml 
  deployment.apps/nfs-provisioner created
  apiVersion: apps/v1
  kind: Deployment
  metadata:
    name: nfs-provisioner
  spec:
    selector:
      matchLabels:
        app: nfs-provisioner
    replicas: 1
    strategy:
      type: Recreate
    template:
      metadata:
        labels:
          app: nfs-provisioner
      spec:
        serviceAccount: nfs-provisioner
        containers:
        - name: nfs-provisioner
          image: registry.cn-beijing.aliyuncs.com/xngczl/nfs-subdir-external-provisione:v4.0.0
          imagePullPolicy: IfNotPresent
          volumeMounts:
          - name: nfs-client-root
            mountPath: /persistentvolumes
          env:
          - name: PROVISIONER_NAME
            value: example.com/nfs
          - name: NFS_SERVER
            value: 192.168.56.129
          - name: NFS_PATH
            value: /home/xy/data/nfs_pro/
  
  [root@anyu967master1 volume]# kubectl get pods
  NAME                               READY   STATUS    RESTARTS      AGE
  nfs-provisioner-8558b45ff5-pkx44   1/1     Running   0             6s
  [root@anyu967master1 volume]# kubectl get storageclass
  NAME   PROVISIONER       RECLAIMPOLICY   VOLUMEBINDINGMODE   ALLOWVOLUMEEXPANSION   AGE
  nfs    example.com/nfs   Delete          Immediate           false                  10s
  [root@anyu967master1 volume]# kubectl apply -f dynamicClaim.yaml 
  persistentvolumeclaim/test-claim1 created
  [root@anyu967master1 volume]# kubectl get pvc
  NAME          STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
  test-claim1   Bound    pvc-414340e3-a0ed-41b8-aeff-d314f237fce5   1Gi        RWX            nfs            9s
  

• 5）StatefulSet 控制器（handleless service）

  StatefulSet是有状态的集合，管理有状态的服务，所管理的Pod的名称不能随意变化。数据持久化的目录也是不一样，每一个Pod都有自己独有的数据持久化存储目录。比如MySQL主从、redis集群等。
  Replicaset、Deployment、DaemonSet都是管理无状态的服务，所管理的Pod的IP、名字、启停顺序等都是随机的。个体对整体无影响，所有pod都是共用一个数据卷的，部署的tomcat就是无状态的服务，tomcat被删除，在启动一个新的tomcat,加入到集群即可，跟tomcat的名字无关。

  点击查看代码

  # Headless Service: 用来定义Pod网络标识，生成可以解析DNS记录；
  # vollumeClaimTemplates: 存储申请模板，创建PVC，指定pvc名称大小，自动创建pvc，且pvc由存储类供应；
  # StatefulSet: 管理pod的
  
  # FQDN：<pod_name>.<svc_name>.<namespace_name>.svc.cluster.local
  
  [root@anyu967master1 statefulset]# cat ./statefulSet.yaml 
  apiVersion: v1
  kind: Service
  metadata:
    name: nginx
    labels:
      app: nginx
  spec:
    ports:
    - port: 80    # service 端口
      name: web
    clusterIP: None
    selector:
      app: nginx  # 标签选择器 选择拥有**app=nginx**标签的pod
  ---
  apiVersion: apps/v1
  kind: StatefulSet
  metadata:
    labels:  # May match selectors of replication controllers and services
      app: sts-nginx
    name: web
  spec:
    selector:
      matchLabels:
        app: nginx
    serviceName: "nginx" # handlerless service的名字
    replicas: 2
    template:
      metadata:
        labels:
          app: nginx  # 标签
      spec:
        containers:
        - name: nginx
          image: nginx
          imagePullPolicy: IfNotPresent
          ports:
          - containerPort: 80
            name: web
          volumeMounts:
          - name: www
            mountPath: /usr/share/nginx/html
    volumeClaimTemplates:
    - metadata:
        name: www
      spec:
        accessModes: ["ReadWriteOnce","ReadWriteMany"]
        storageClassName: nfs-web  # 指定从哪个存储类申请pv
        resources:
          requests:
            storage: 1Gi  # 需要1Gi的pv 会自动跟符合条件的pv绑定