K8s（九）持久化存储PV与PVC

PV和PVC

PV 和 PVC 之间的关系是一种动态的供需匹配关系。PVC 表示应用程序对持久化存储的需求，而 PV 表示可用的持久化存储资源。Kubernetes 控制平面会根据 PVC 的需求来选择和绑定合适的 PV，将其挂载到应用程序的 Pod 中，从而使应用程序可以访问持久化存储。

PV可以静态或动态的创建；PV和PVC必须一一对应；PVC如果没有对应的绑定PV则会Pending

PVC被删除后，PV内的数据有两种处理策略分别是Retain保留（默认）、Delete删除

接下来的实验中会对这几种模式进行测试，测试结果发现并没有什么区别（k8s1.26）

静态创建PV

#绑定master2节点的/dirfornfs
yum -y install nfs-utils
#创建一个新的nfs目录，并添加到/etc/exports文件中
mkdir -p /dirfornfs/{1..5}
#
echo "/dirfornfs *(rw,no_root_squash)
/dirfornfs/1 *(rw,no_root_squash)
/dirfornfs/2 *(rw,no_root_squash)
/dirfornfs/3 *(rw,no_root_squash)
/dirfornfs/4 *(rw,no_root_squash)
/dirfornfs/5 *(rw,no_root_squash)" > /etc/exports
#创建pv资源
cat > jintai-PV.yaml << EOF
apiVersion: v1
kind: PersistentVolume
metadata: 
  name: jintai-pv1
  labels:
     stor: pv1
spec: 
  nfs: 
    server: 192.168.8.159
    path: /dirfornfs/1
  accessModes: ["ReadWriteOnce"]  #访问模式 只支持同一node的读写
  capacity:
     storage: 1.5Gi  #分配1.5个G
---
apiVersion: v1
kind: PersistentVolume
metadata: 
  name: jintai-pv2
  labels:
     stor: pv2
spec: 
  nfs: 
    server: 192.168.8.159
    path: /dirfornfs/2
  accessModes: ["ReadWriteMany"] #支持多个node读写
  capacity:
     storage: 2Gi  #分配2个G
---
apiVersion: v1
kind: PersistentVolume
metadata: 
  name: jintai-pv3
  labels:
     stor: pv3
spec: 
  nfs: 
    server: 192.168.8.159
    path: /dirfornfs/3
  accessModes: ["ReadOnlyMany"]  #多个node只读
  capacity:
     storage: 3Gi  #分配3个G
EOF
kubectl apply -f jintai-PV.yaml
kubectl get pv
NAME         CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS     
jintai-pv1   1536Mi     RWO            Retain           Available   #单节点读写   
jintai-pv2   2Gi        RWX            Retain           Available   #多节点读写   
jintai-pv3   3Gi        ROX            Retain           Available   #多节点只读

#创建pvc
cat > pvc.yaml << EOF
apiVersion: v1
kind: PersistentVolumeClaim
metadata: 
  name: pvc1
spec:
  accessModes: ["ReadWriteOnce"] #对应的pv必须访问模式保持相同
  selector: 
    matchLabels:
       stor: pv1
  resources:
     requests:
       storage: 1.5Gi
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata: 
  name: pvc2
spec:
  accessModes: ["ReadWriteMany"] #对应的pv必须访问模式保持相同
  selector: 
    matchLabels:
       stor: pv2
  resources:
     requests:
       storage: 2Gi
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata: 
  name: pvc3
spec:
  accessModes: ["ReadOnlyMany"] #对应的pv必须访问模式保持相同
  selector: 
    matchLabels:
       stor: pv3 #对应上pv的标签
  resources:
     requests:
       storage: 3Gi
EOF
kubectl apply -f pvc.yaml
kubectl get pvc
NAME   STATUS   VOLUME       CAPACITY   ACCESS MODES   STORAGECLASS   AGE
pvc1   Bound    jintai-pv1   1536Mi     RWO                           54s
pvc2   Bound    jintai-pv2   2Gi        RWX                           54s
pvc3   Bound    jintai-pv3   3Gi        ROX                           54s

#创建pod1，让pvc1挂载上去
cat > pod-pvc.yaml << EOF
apiVersion: apps/v1
kind: Deployment
metadata:
  name: pod-pvc1
spec:
  replicas: 3
  selector:
    matchLabels:
      stor: pvc
  template:
    metadata:
      labels:
        stor: pvc
    spec:
      containers:
      - name: test
        image: docker.io/library/nginx
        imagePullPolicy: IfNotPresent
        volumeMounts:
        - mountPath: /usr/share/nginx/html
          name: pvc1
      volumes:
      - name: pvc1
        persistentVolumeClaim:
          claimName: pvc1
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: pod-pvc2
spec:
  replicas: 3
  selector:
    matchLabels:
      stor: pvc
  template:
    metadata:
      labels:
        stor: pvc
    spec:
      containers:
      - name: test
        image: docker.io/library/nginx
        imagePullPolicy: IfNotPresent
        volumeMounts:
        - mountPath: /usr/share/nginx/html
          name: pvc2
      volumes:
      - name: pvc2
        persistentVolumeClaim:
          claimName: pvc2
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: pod-pvc3
spec:
  replicas: 3
  selector:
    matchLabels:
      stor: pvc
  template:
    metadata:
      labels:
        stor: pvc
    spec:
      containers:
      - name: test
        image: docker.io/library/nginx
        imagePullPolicy: IfNotPresent
        volumeMounts:
        - mountPath: /usr/share/nginx/html
          name: pvc3
      volumes:
      - name: pvc3
        persistentVolumeClaim:
          claimName: pvc3
EOF
kubectl apply -f pod-pvc.yaml
kubectl get pods -owide
NAME                        READY   STATUS    RESTARTS   AGE   IP             NODE           NOMINATED NODE   READINESS GATES
pod-pvc1-69b655447-5zmjn    1/1     Running   0          95s   10.10.179.12   ws-k8s-node1              
pod-pvc1-69b655447-crnfr    1/1     Running   0          95s   10.10.179.11   ws-k8s-node1              
pod-pvc1-69b655447-kzpf5    1/1     Running   0          95s   10.10.234.75   ws-k8s-node2              
pod-pvc2-697979cddb-6x658   1/1     Running   0          95s   10.10.179.13   ws-k8s-node1              
pod-pvc2-697979cddb-bxcxm   1/1     Running   0          95s   10.10.179.15   ws-k8s-node1              
pod-pvc2-697979cddb-zffwh   1/1     Running   0          95s   10.10.234.74   ws-k8s-node2              
pod-pvc3-7588fbc489-2v8pt   1/1     Running   0          95s   10.10.179.14   ws-k8s-node1              
pod-pvc3-7588fbc489-5scpd   1/1     Running   0          95s   10.10.234.76   ws-k8s-node2              
pod-pvc3-7588fbc489-b7cp9   1/1     Running   0          95s   10.10.234.77   ws-k8s-node2              
#进入不同node节点的pod查看是否同步
#pvc1
kubectl exec -it pod-pvc1-69b655447-5zmjn -- /bin/bash
cd  /usr/share/nginx/html/
touch 11
exit
kubectl exec -it pod-pvc1-69b655447-kzpf5  -- /bin/bash
ls /usr/share/nginx/html/11
/usr/share/nginx/html/11 #不同节点依然可以同时访问到这个pv

#pvc2也可以，略过了

#pvc3  ACCESS MODES为ROX，无法创建
root@pod-pvc3-7588fbc489-b7cp9:/# touch 123454 /usr/share/nginx/html/
root@pod-pvc3-7588fbc489-b7cp9:/#
root@pod-pvc3-7588fbc489-b7cp9:/# ls /usr/share/nginx/html/ 
root@pod-pvc3-7588fbc489-b7cp9:/# 无输出
#
#删除
kubectl delete -f pod-pvc.yaml
kubectl delete -f pvc.yaml
kubectl delete -f jintai-PV.yaml
#启用
kubectl apply -f jintai-PV.yaml
kubectl apply -f pvc.yaml
kubectl apply -f pod-pvc.yaml
kubectl exec -it pod-pvc1-69b655447-46h5h -- /bin/bash
ls /usr/share/nginx/html/
11 #依然保留了数据

#修改回收策略
#
vim jintai-PV.yaml
...
capacity:
     storage: 1.5Gi  #分配1.5个G
persistentVolumeReclaimPolicy: Delete #回收策略为Delete
---
...
kubectl delete -f pod-pvc.yaml
kubectl delete -f pvc.yaml
kubectl delete -f jintai-PV.yaml
kubectl apply -f jintai-PV.yaml
kubectl apply -f pvc.yaml
kubectl apply -f pod-pvc.yaml

#创建一个新pod关联pvc1
cat > pod-test.yaml << EOF
apiVersion: v1
kind: Pod
metadata:
  name: pod-pvc-test
spec:
    containers:
      - name: test10
        image: docker.io/library/nginx
        imagePullPolicy: IfNotPresent
        volumeMounts:
        - mountPath: /usr/share/nginx/html
          name: pvc1
    volumes:
      - name: pvc1
        persistentVolumeClaim:
          claimName: pvc1
EOF
kubectl apply -f pod-test.yaml
#使用测试pod新建文件
kubectl exec -it pod-pvc-test -- /bin/bash
cd  /usr/share/nginx/html/
mkdir 123
exit 
#进入另一个pod查看
kubectl exec -it pod-pvc1-69b655447-7lxwl  -- /bin/bash
ls /usr/share/nginx/html/
123  12345
#删除新建文件的测试pod
kubectl delete -f pod-test.yaml
#在另一个查看
ls /usr/share/nginx/html/
123  12345 #依然存在
#
#回收策略Delete和Retain没什么区别，都不会被删除
#清理
kubectl delete -f pod-pvc.yaml
kubectl delete -f pvc.yaml
kubectl delete -f jintai-PV.yaml

StorageClass创建pv

#查看帮助
kubectl explain storageclass
allowVolumeExpansion  # 是否允许持久卷的扩展，不能支持缩小
allowedTopologies <[]Object> # 定义允许使用该StorageClass的节点拓扑约束
apiVersion  
kind  
metadata