【云原生】PV PVC原理及完整流程

一、PV和PVC

1.PV是什么

给pod存数据的硬盘

2.PVC是什么

pod向k8s要硬盘的申请单

3.PV和PVC的关系是什么

如果没有storageClass，pv是提前创建好的，pvc也是提前创建好的，k8s根据pvc找到pv
如果有storageClass，k8s会根据pvc的申请自动创建一个pv

二、NFS Provisioner

1.NFS是什么

Network File System 让多台电脑共享同一个文件夹的网络存储
网络存储：通常在一台专门的服务，其他电脑通过网络访问这些数据

2.Provisioner是什么

供应者 提供者

3.NFS Provisioner 的流程

1.pvc发起请求 并指定 storageClassName
2.storageClass 告诉k8s 用哪个provisoner
3.Provisoner自动在nfs上创建子目录，生成PV
4.PVC与PV绑定
5.pod挂载与PVC使用数据

4.Provisioner如何自动创建PV

1.Provisioner是一个控制器 它一直在监听pvc的创建
2.当有pvc时，它根据pvc的声明去调用底层接口命令创建pv
3.然后pvc和pv绑定

5.NFS proversioner如何实现

1.准备NFS服务器
2.通过yaml部署NFS Provisioner

三、PV，PVC，storageClass，Provisioner的全部流程

1.创建StorageClass

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: nfs
provisioner: cluster.local/nfs-provisioner  # 必须与Provisioner的标识一致
parameters:
  archiveOnDelete: "false"  # 删除PVC时是否保留数据
mountOptions:
  - vers=4.1                # macOS必须指定NFS版本
  - noresvport
reclaimPolicy: Retain
volumeBindingMode: Immediate

2.创建nfs-provisioner的yaml

# nfs-provisioner.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nfs-provisioner
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nfs-provisioner
  template:
    metadata:
      labels:
        app: nfs-provisioner
    spec:
      serviceAccountName: nfs-provisioner
      containers:
      - name: nfs-provisioner
        image: k8s.gcr.io/sig-storage/nfs-subdir-external-provisioner:v4.0.2
        env:
        - name: PROVISIONER_NAME
          value: cluster.local/nfs-provisioner  # 必须与StorageClass的provisioner字段一致
        - name: NFS_SERVER
          value: "host.docker.internal"         # macOS专用域名
        - name: NFS_PATH
          value: "/Users/Shared/nfs_k8s_data"   # 修改为您的共享目录路径
        volumeMounts:
        - name: nfs-client-root
          mountPath: /persistentvolumes
      volumes:
      - name: nfs-client-root
        nfs:
          server: host.docker.internal
          path: /Users/Shared/nfs_k8s_data      # 与NFS_PATH一致
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: nfs-provisioner
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: nfs-provisioner-runner
rules:
  - apiGroups: [""]
    resources: ["persistentvolumes"]
    verbs: ["get", "list", "watch", "create", "delete"]
  - apiGroups: [""]
    resources: ["persistentvolumeclaims"]
    verbs: ["get", "list", "watch", "update"]
  - apiGroups: ["storage.k8s.io"]
    resources: ["storageclasses"]
    verbs: ["get", "list", "watch"]
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: run-nfs-provisioner
subjects:
  - kind: ServiceAccount
    name: nfs-provisioner
    namespace: default
roleRef:
  kind: ClusterRole
  name: nfs-provisioner-runner
  apiGroup: rbac.authorization.k8s.io

3.创建PVC

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: test-pvc
spec:
  storageClassName: nfs  # 必须与StorageClass名称匹配
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 1Gi

4.部署所有yaml文件，然后查看状态

kubectl apply -f test-pvc.yaml
kubectl get pvc test-pvc -w