LAB-13：创建PVC

LAB-13：创建PVC

LAB 概述

创建一个名字为 pv-volume 的 pvc，指定 storageClass 为 csi-hostpath-sc，大小为10Mi。
然后创建一个 Pod，名字为 web-server，镜像为 nginx，并且挂载该 PVC 至 /usr/share/nginx/html，挂载的权限为 ReadWriteOnce。
之后通过 kubectl edit 或者 kubectl path 将 pvc 改成 70Mi，并且记录修改记录。

LAB 预配

# 使用 NFS 配置 storageClass
# 1、配置 NFS 共享存储
# 创建 NFS 服务器
user1@k8s-master:~$ sudo apt-get install -y nfs-kernel-server

# 配置 NFS 文件共享。
user1@k8s-master:~$ sudo mkdir /nfs-server
user1@k8s-master:~$ cat /etc/exports 
/nfs-server *(rw,sync,no_root_squash)
user1@k8s-master:~$ sudo chmod 700 /nfs-server/
user1@k8s-master:~$ sudo service nfs-kernel-server restart
user1@k8s-master:~$ sudo service nfs-kernel-server status

# 验证NFS服务。
user1@k8s-master:~$ sudo showmount -e 127.0.0.1
Export list for 127.0.0.1:
/nfs-server *

# 在所有 node 节点也要安装 nfs client 软件。并且测试一下 nfs 存储
user1@k8s-node-2:~$ sudo apt-get install -y nfs-kernel-server
user1@k8s-node-2:~$ sudo showmount -e k8s-master
Export list for k8s-master:
/nfs-server *

# 2、配置 storageClass
# 需要一个对应的 provisioner 来自动创建 PV，这里使用的 NFS 存储，则可以使用 nfs-subdir-external-provisioner 这个 Provisioner，它使用现有的和已配置的 NFS 服务器来支持通过 PVC 动态配置 PV。链接如下：https://github.com/kubernetes-sigs/nfs-subdir-external-provisioner/tree/master/deploy

# 创建 ServiceAccount 解决权限问题。
# 编写 RBAC 资源清单文件
user1@k8s-master:~/cka-2022-05-01/13$ cat rbac.yaml 
apiVersion: v1
kind: ServiceAccount
metadata:
  name: nfs-client-provisioner
  namespace: default
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: nfs-client-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"]
  - apiGroups: [""]
    resources: ["events"]
    verbs: ["create", "update", "patch"]
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: run-nfs-client-provisioner
subjects:
  - kind: ServiceAccount
    name: nfs-client-provisioner
    namespace: default
roleRef:
  kind: ClusterRole
  name: nfs-client-provisioner-runner
  apiGroup: rbac.authorization.k8s.io
---
kind: Role
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: leader-locking-nfs-client-provisioner
  namespace: default
rules:
  - apiGroups: [""]
    resources: ["endpoints"]
    verbs: ["get", "list", "watch", "create", "update", "patch"]
---
kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: leader-locking-nfs-client-provisioner
subjects:
  - kind: ServiceAccount
    name: nfs-client-provisioner
    namespace: default
roleRef:
  kind: Role
  name: leader-locking-nfs-client-provisioner
  apiGroup: rbac.authorization.k8s.io

# 创建 RBAC 资源
user1@k8s-master:~/cka-2022-05-01/13$ kubectl apply -f rbac.yaml

# 编写 nfs-client 的资源清单文件
user1@k8s-master:~/cka-2022-05-01/13$ cat nfs-client-provisioner.yaml 
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nfs-client-provisioner
  labels:
    app: nfs-client-provisioner
  namespace: default
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nfs-client-provisioner
  strategy:
    type: Recreate
  selector:
    matchLabels:
      app: nfs-client-provisioner
  template:
    metadata:
      labels:
        app: nfs-client-provisioner
    spec:
      serviceAccountName: nfs-client-provisioner
      containers:
        - name: nfs-client-provisioner
          image: quay.io/external_storage/nfs-client-provisioner:latest
          volumeMounts:
            - name: nfs-client-root
              mountPath: /persistentvolumes
          env:
            - name: PROVISIONER_NAME
              value: nfs-storage  # provisioner 的名称，后面创建SC使用
            - name: NFS_SERVER
              value: k8s-master   # nfs server: k8s-master
            - name: NFS_PATH  
              value: /nfs-server  # nfs 共享的目录
      volumes:
        - name: nfs-client-root
          nfs:
            server: k8s-master
            path: /nfs-server

# 创建 nfs-client 资源
user1@k8s-master:~/cka-2022-05-01/13$ kubectl apply -f nfs-client-provisioner.yaml

# 查看 nfs-client 的 pod
user1@k8s-master:~$ kubectl get pod nfs-client-provisioner-6546c4b76-zw2k2 
NAME                                     READY   STATUS    RESTARTS      AGE
nfs-client-provisioner-6546c4b76-zw2k2   1/1     Running   0             30s

# 编写 storageclass 资源清单
# 注意: allowVolumeExpansion 可以根据情况是否设置为 true (默认为 false ), allowVolumeExpansion 为 flase 时不能动态扩容（例如不能直接修改 pvc 大小，当 allowVolumeExpansion 为 true 时可以修改）
user1@k8s-master:~/cka-2022-05-01/13$ cat managed-nfs-storageclass.yaml 
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: csi-hostpath-sc
provisioner: nfs-storage
allowVolumeExpansion: true

# 创建 storageclass 资源
user1@k8s-master:~/cka-2022-05-01/13$ kubectl apply -f managed-nfs-storageclass.yaml  
storageclass.storage.k8s.io/csi-hostpath-sc created

# 查看 storageclass 资源
user1@k8s-master:~$ kubectl get storageclasses.storage.k8s.io csi-hostpath-sc 
NAME              PROVISIONER   RECLAIMPOLICY   VOLUMEBINDINGMODE   ALLOWVOLUMEEXPANSION   AGE
csi-hostpath-sc   nfs-storage   Delete          Immediate           true                   36s

# 有可能出现错误：k8s升级到1.20.X以上版本时，nfs-client-provisioner 启动中出现了报错，可以修改 /etc/kubernetes/manifests/kube-apiserver.yaml，增加’–feature-gates=RemoveSelfLink=false’的参数。
user1@k8s-master:~$ sudo cat /etc/kubernetes/manifests/kube-apiserver.yaml
apiVersion: v1
···
    - --tls-private-key-file=/etc/kubernetes/pki/apiserver.key
    - --feature-gates=RemoveSelfLink=false # 添加这个配置

# 重启 kubelet.service 
user1@k8s-master:~$ sudo systemctl restart kubelet.service 

# 具体错误如下：
$ kubectl describe pod nfs-client-provisioner-6546c4b76-mgxv7 
......
persistentvolume-controller  waiting for a volume to be created, either by external provisioner "nfs-storage" or manually created by system administrator

# pvc pending 状态
$ kubectl describe pvc pv-volume 
 Normal  ExternalProvisioning  13s (x3 over 35s)  persistentvolume-controller  waiting for a volume to be created, either by external provisioner "nfs-storage" or manually created by system administrator

 LAB 答案

# 切换 content
$ kubectl config use-context k8s

# 编写 yaml 文件
$ cat pv-volume.yaml 
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pv-volume
spec:
  storageClassName: csi-hostpath-sc
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 10Mi
---
apiVersion: v1
kind: Pod
metadata:
  name: web-server
spec:
  volumes:
    - name: task-pv-storage
      persistentVolumeClaim:
        claimName: pv-volume
  containers:
    - name: web-server
      image: nginx:1.18.0
      ports:
        - containerPort: 80
          name: "http-server"
      volumeMounts:
        - mountPath: "/usr/share/nginx/html"
          name: task-pv-storage

# 执行 yaml 文件
user1@k8s-master:~/cka-2022-05-01/13$ kubectl apply -f pv-volume.yaml 

# 扩容（注，NFS 不支持扩容）修改为70Mi
# 方式1: Patch
$ kubectl patch pvc pv-volume  -p '{"spec":{"resources":{"requests":{"storage": "70Mi"}}}}' --record

# 方式2: edit
$ kubectl  edit pvc pv-volume

 LAB 验证

# 查看 PVC
user1@k8s-master:~$ kubectl get pvc
NAME        STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS      AGE
pv-volume   Bound    pvc-39e0aef5-21da-4af3-b375-6e9744da3f78   10Mi       RWO            csi-hostpath-sc   6m54s

# 查看 nfs 上多了一个目录
user1@k8s-master:~$ sudo ls -d /nfs-server/default-pv-volume-pvc-39e0aef5-21da-4af3-b375-6e9744da3f78 
/nfs-server/default-pv-volume-pvc-39e0aef5-21da-4af3-b375-6e9744da3f78

# 在 NFS 上写入 index.html
user1@k8s-master:~$ sudo sh -c 'echo "http-server storageclass" > /nfs-server/default-pv-volume-pvc-39e0aef5-21da-4af3-b375-6e9744da3f78/index.html'

# 测试访问
user1@k8s-master:~$ kubectl get pod web-server  -o wide
NAME         READY   STATUS    RESTARTS   AGE   IP              NODE         NOMINATED NODE   READINESS GATES
web-server   1/1     Running   0          16m   10.244.76.155   k8s-node-3   <none>           <none>
user1@k8s-master:~$ curl 10.244.76.155
http-server storageclass

 

参考资料

• https://kubernetes.io/zh/docs/tasks/configure-pod-container/configure-persistent-volume-storage/