PV和PVC

PV（PersistentVolume）在宣告的時候需要指定大小和續寫模式:["ReadWriteMany","ReadWriteOnce","ReadOnlyMany"],pv是叢集宣告的儲存資源

實際資源部署請求的儲存空間，稱為PVC(PersistentVolumeClaim)。 pvc宣告時也需要指定讀寫模式和大小。pvc關聯某個pv後這個pv就不能再和別的pvc關聯了。k8s會根據pvc的大小和讀寫模式在可用的PV中匹配一個最佳的pv與pvc關聯。

PV的資源回收策略

PV、PVC定義檔案以及建立

#PV的定義檔案
[root@k8s-01 ~]# cat pv_mysql_wordpress.yml 
apiVersion: v1
kind: PersistentVolume
metadata:
    name: mysql-pv
spec:
    capacity:
        storage: 3Gi
    accessModes: ["ReadWriteOnce"]
    persistentVolumeReclaimPolicy: Recycle
    nfs:
        path: 
 
/kube/mysql-db
        server: k8s-01
---
apiVersion: v1
kind: PersistentVolume
metadata:
    name: wordpress-pv
spec:
    capacity:
        storage: 1Gi
    accessModes: ["ReadWriteOnce","ReadWriteMany"]
    persistentVolumeReclaimPolicy: Recycle
    nfs:
        path: /kube/wordpress
        server: k8s
 
-01

#建立PV和查詢
[root@k8s-01 ~]# kubectl create -f pv_mysql_wordpress.yml

#查詢PV

[root@k8s-01 ~]# kubectl get pv -o wide
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE VOLUMEMODE
mysql-pv 3Gi RWO Recycle Bound default/mysql-pv-claim 50d Filesystem
wordpress-pv 1Gi RWO,RWX Recycle Bound default/wordpress-pv-claim 50d Filesystem

PVC定義檔案以及建立操作

#mysql和wordpress pvc定義檔案
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
    name: mysql-pv-claim
spec:
    accessModes: ["ReadWriteOnce"]
    resources:
        requests:
            storage: 2Gi
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
    name: wordpress-pv-claim
spec:
    accessModes: ["ReadWriteOnce","ReadWriteMany"]
    resources:
        requests:
            storage: 1Gi

#建立PVC 
kubectl create -f pvc_mysql_wd.yml

#查詢建立的PVC，這裡能看到PVC根據大小和讀寫策略自動匹配到合適的PV
[root@k8s-01 ~]# kubectl get pvc -o wide
NAME                 STATUS   VOLUME         CAPACITY   ACCESS MODES   STORAGECLASS   AGE   VOLUMEMODE
mysql-pv-claim       Bound    mysql-pv       3Gi        RWO                           50d   Filesystem
wordpress-pv-claim   Bound    wordpress-pv   1Gi        RWO,RWX                       50d   Filesystem