本示例中会创建多个pv、pvc示例以验证pvc在挑选pvc时的策略，pv所使用的后端存储为nfs。

创建nfs共享目录

在nfs-server上创建出共享的目录

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# 创建出目录
[root@nfs ~]# mkdir /data/redis00{1,2,3,4,5}

# 修改nfs配置文件
[root@nfs data]# vim /etc/exports
/data/redis     172.16.11.0/24(rw)
/data/redis001  172.16.11.0/24(rw)
/data/redis002  172.16.11.0/24(rw)
/data/redis003  172.16.11.0/24(rw)
/data/redis004  172.16.11.0/24(rw)
/data/redis005  172.16.11.0/24(rw)

# 重新导出目录
[root@nfs data]# exportfs -ar
[root@nfs data]# exportfs 
/data/redis     172.16.11.0/24
/data/redis001  172.16.11.0/24
/data/redis002  172.16.11.0/24
/data/redis003  172.16.11.0/24
/data/redis004  172.16.11.0/24
/data/redis005  172.16.11.0/24

# 将该目录下目录的属主改为999
[root@nfs data]# chown 999 ./*
[root@nfs data]# ll
total 24
drwxr-xr-x 2 systemd-coredump root 4096 Jul 13 14:47 redis
drwxr-xr-x 2 systemd-coredump root 4096 Jul 13 17:49 redis001
drwxr-xr-x 2 systemd-coredump root 4096 Jul 13 17:47 redis002
drwxr-xr-x 2 systemd-coredump root 4096 Jul 13 17:49 redis003
drwxr-xr-x 2 systemd-coredump root 4096 Jul 13 17:49 redis004
drwxr-xr-x 2 systemd-coredump root 4096 Jul 13 17:49 redis005

PV定义示例

1.创建资源清单

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# pv-nfs-demo资源清单，大小5Gi，多路读写
root@k8s-master01:~/yaml/chapter05# vim pv-nfs-demo.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv-nfs-demo
spec:
  capacity:
    storage: 5Gi
  volumeMode: Filesystem
  accessModes:
  - ReadWriteMany                             # 多路读写
  persistentVolumeReclaimPolicy: Retain				# PV回收策略为保留
  mountOptions:
  - hard  
  - nfsvers=4.1
  nfs:
    path: "/data/redis001"
    server: 172.16.11.79
    
# pv-nfs-001资源清单，访问模式RWM，大小10Gi
root@k8s-master01:~/yaml/chapter05# vim pv-nfs-002.yaml
apiVersion: v1
kind: PersistentVolume
metadata: 
  name: pv-nfs-002
spec:
  capacity:
    storage: 10Gi
  volumeMode: Filesystem
  accessModes:
  - ReadWriteMany
  persistentVolumeReclaimPolicy: Retain
  mountOptions:
  - hard  
  - nfsvers=4.1
  nfs:
    path: "/data/redis002"
    server: 172.16.11.79

# pv-nfs-003资源清单，访问模式RWO，大小1Gi
root@k8s-master01:~/yaml/chapter05# vim pv-nfs-003.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv-nfs-003
spec:
  capacity:
    storage: 1Gi
  volumeMode: Filesystem
  accessModes:
  - ReadWriteOnce
  persistentVolumeReclaimPolicy: Retain
  mountOptions:
  - hard  
  - nfsvers=4.1
  nfs:
    path: "/data/redis003"
    server: 172.16.11.79

2.创建出pv

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root@k8s-master01:~/yaml/chapter05# kubectl apply -f pv-nfs-demo.yaml -f pv-nfs-002.yaml -f pv-nfs-003.yaml 
persistentvolume/pv-nfs-demo created
persistentvolume/pv-nfs-002 created
persistentvolume/pv-nfs-003 created

# get pv资源
root@k8s-master01:~/yaml/chapter05# kubectl get pv
NAME          CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS      CLAIM   STORAGECLASS   REASON   AGE
pv-nfs-002    10Gi       RWX            Retain           Available                                   98m
pv-nfs-003    1Gi        RWO            Retain           Available                                   98m
pv-nfs-demo   5Gi        RWX            Retain           Available                                   98m

pvc定义示例

1.创建资源清单

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# 创建pvc资源清单，要求访问模式RWM，指定pv大小，最大10Gi最小3Gi
root@k8s-master01:~/yaml/chapter05# vim pvc-demo-001.yaml 
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pvc-demo-001
  namespace: default
spec:
  accessModes: ["ReadWriteMany"]
  volumeMode: Filesystem
  resources:
    requests:
      storage: 3Gi     # 最小3Gi
    limits:
      storage: 10Gi    # 最大10Gi
      
# 创建pvc资源清单，要求pv的访问模型为RWO，PV大小最大2Gi，最小5Gi
root@k8s-master01:~/yaml/chapter05# vim pvc-demo-002.yaml 
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pvc-demo-002
spec:
  accessMode: ["ReadWriteOnce"]
  volumeMode: Filesystem
  resource:
    requests:
      storage: 2Gi
    limits:
      storage: 5Gi
  selector:
    matchLabels:
      usedof: "redisdata"

2.应用pvc配置清单

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root@k8s-master01:~/yaml/chapter05# kubectl apply -f pvc-demo-001.yaml 
persistentvolumeclaim/pvc-demo-001 created

# 可以看到pvc资源已经被创建
root@k8s-master01:~/yaml/chapter05# kubectl get pvc
NAME           STATUS   VOLUME        CAPACITY   ACCESS MODES   STORAGECLASS   AGE
pvc-demo-001   Bound    pv-nfs-demo   5Gi        RWX                           6s

# 查看哪个pv被关联
root@k8s-master01:~/yaml/chapter05# kubectl get pv
NAME          CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS      CLAIM                  STORAGECLASS   REASON   AGE
pv-nfs-002    10Gi       RWX            Retain           Available                                                  117m
pv-nfs-003    1Gi        RWO            Retain           Available                                                  117m
pv-nfs-demo   5Gi        RWX            Retain           Bound       default/pvc-demo-001                           117m
# 5G的pv被关联，因为pvc-demo-001请求的大小为2Gi，RWM，Filesystem，而5Gi大小的PV符合其要求。

Pod中使用PVC来挂载卷

1.创建资源清单

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root@k8s-master01:~/yaml/chapter05# vim volumes-pvc-demo.yaml
apiVersion: v1
kind: Pod
metadata:
  name: volumes-pvc-demo
  namespace: default
spec:
  containers:
  - name: redis
    image: redis:alpine
    imagePullPolicy: IfNotPresent
    ports:
    - containerPort: 6379
      name: redisport
    volumeMounts:
    - mountPath: /data
      name: redis-rbd-vol
    securityContext:
      runAsUser: 999
      runAsGroup: 999
  volumes:
  - name: redis-rbd-vol								# 定义卷名称
    persistentVolumeClaim:						# 使用PVC
      claimName: pvc-demo-001         # 绑定创建的pvc-demo-001的pvc

2.应用配置清单

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root@k8s-master01:~/yaml/chapter05# kubectl apply -f volumes-pvc-demo.yaml 
pod/volumes-pvc-demo created

# 创建成功
root@k8s-master01:~/yaml/chapter05# kubectl get pods volumes-pvc-demo 
NAME               READY   STATUS    RESTARTS   AGE
volumes-pvc-demo   1/1     Running   0          10s

3.进入容器验证

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# 可以看到已经被挂载
root@k8s-master01:~/yaml/chapter05# kubectl exec volumes-pvc-demo -- mount | grep "data"
172.16.11.79:/data/redis001 on /data type nfs4 (rw,relatime,vers=4.1,rsize=1048576,wsize=1048576,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,clientaddr=172.16.11.83,local_lock=none,addr=172.16.11.79)

总结

以上可以看出用户只需要定义pvc，以及pod，而存储相关的细节只需要交给管理员即可。