k8s PersistentVolume筆記

原因

在業(yè)務(wù)中需要使用kubernetes.Clientset創(chuàng)建容器，創(chuàng)建時(shí)需要對(duì)容器進(jìn)行綁定PersistentVolume所以要對(duì)其進(jìn)行一番了解

參考文檔

配置 Pod 以使用 PersistentVolume 作為存儲(chǔ)
Binding Persistent Volumes by Labels
改變默認(rèn) StorageClass

測(cè)試方式

完成k8s文檔中的測(cè)試用例

done.

根據(jù)當(dāng)前項(xiàng)目測(cè)試

問題1: storageClassName是否必須存在

根據(jù)Binding Persistent Volumes by Labels文檔中表明PersistentVolumeClaim可以使用

selector: 
    matchLabels:
      storage-tier: gold
      aws-availability-zone: us-east-1

來匹配對(duì)應(yīng)的PersistentVolume而不用指定StorageClassName
我將三個(gè)yaml復(fù)制到此處
glusterfs-pv.yaml

apiVersion: v1
kind: PersistentVolume
metadata:
  name: gluster-volume
  labels: 
    storage-tier: gold
    aws-availability-zone: us-east-1
spec:
  capacity:
    storage: 2Gi
  accessModes:
    - ReadWriteMany
  glusterfs:
    endpoints: glusterfs-cluster 
    path: myVol1
    readOnly: false
  persistentVolumeReclaimPolicy: Retain

glusterfs-pvc.yaml

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: gluster-claim
spec:
  accessModes:
  - ReadWriteMany
  resources:
     requests:
       storage: 1Gi
  selector: 
    matchLabels:
      storage-tier: gold
      aws-availability-zone: us-east-1

Volume Endpoints
glusterfs-ep.yaml

  apiVersion: v1
  kind: Endpoints
  metadata:
    name: glusterfs-cluster
  subsets:
    - addresses:
        - ip: 192.168.122.221
      ports:
        - port: 1
    - addresses:
        - ip: 192.168.122.222
      ports:
        - port: 1

實(shí)際測(cè)試時(shí),獲取版本

qiantao@qiant k8s % kubectl version -o yaml
clientVersion:
  buildDate: "2020-02-11T18:14:22Z"
  compiler: gc
  gitCommit: 06ad960bfd03b39c8310aaf92d1e7c12ce618213
  gitTreeState: clean
  gitVersion: v1.17.3
  goVersion: go1.13.6
  major: "1"
  minor: "17"
  platform: darwin/amd64
serverVersion:
  buildDate: "2020-01-15T08:18:29Z"
  compiler: gc
  gitCommit: e7f962ba86f4ce7033828210ca3556393c377bcc
  gitTreeState: clean
  gitVersion: v1.16.6-beta.0
  goVersion: go1.13.5
  major: "1"
  minor: 16+
  platform: linux/amd64

獲取endpoints

qiantao@qiant k8s % kubectl get endpoints
NAME                ENDPOINTS                             AGE
glusterfs-cluster   192.168.122.221:1,192.168.122.222:1   4m32s
kubernetes          192.168.65.3:6443                     12d

獲取pvc信息

qiantao@qiant k8s % kubectl get pvc gluster-claim -o yaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  annotations:
    pv.kubernetes.io/bind-completed: "yes"
    pv.kubernetes.io/bound-by-controller: "yes"
    volume.beta.kubernetes.io/storage-provisioner: docker.io/hostpath
  creationTimestamp: "2020-07-13T12:05:42Z"
  finalizers:
  - kubernetes.io/pvc-protection
  name: gluster-claim
  namespace: default
  resourceVersion: "201203"
  selfLink: /api/v1/namespaces/default/persistentvolumeclaims/gluster-claim
  uid: 977b792d-fc2f-440c-9746-b4670250a239
spec:
  accessModes:
  - ReadWriteMany
  resources:
    requests:
      storage: 1Gi
  selector:
    matchLabels:
      aws-availability-zone: us-east-1
      storage-tier: gold
  storageClassName: hostpath
  volumeMode: Filesystem
  volumeName: pvc-977b792d-fc2f-440c-9746-b4670250a239
status:
  accessModes:
  - ReadWriteMany
  capacity:
    storage: 1Gi
  phase: Bound

發(fā)現(xiàn)對(duì)應(yīng)的PersistentVolume居然是pvc-977b792d-fc2f-440c-9746-b4670250a239,發(fā)生了什么???

獲取一下我們?cè)O(shè)置的gluster-volume和pvc-977b792d-fc2f-440c-9746-b4670250a239

qiantao@qiant k8s % kubectl get pv pvc-977b792d-fc2f-440c-9746-b4670250a239 gluster-volume -o yaml
apiVersion: v1
items:
- apiVersion: v1
  kind: PersistentVolume
  metadata:
    annotations:
      docker.io/hostpath: /var/lib/k8s-pvs/gluster-claim/pvc-977b792d-fc2f-440c-9746-b4670250a239
      pv.kubernetes.io/provisioned-by: docker.io/hostpath
    creationTimestamp: "2020-07-13T12:05:42Z"
    finalizers:
    - kubernetes.io/pv-protection
    name: pvc-977b792d-fc2f-440c-9746-b4670250a239
    resourceVersion: "201200"
    selfLink: /api/v1/persistentvolumes/pvc-977b792d-fc2f-440c-9746-b4670250a239
    uid: 1269e814-3d66-4757-b379-c1d65b6bd178
  spec:
    accessModes:
    - ReadWriteMany
    capacity:
      storage: 1Gi
    claimRef:
      apiVersion: v1
      kind: PersistentVolumeClaim
      name: gluster-claim
      namespace: default
      resourceVersion: "201195"
      uid: 977b792d-fc2f-440c-9746-b4670250a239
    hostPath:
      path: /var/lib/k8s-pvs/gluster-claim/pvc-977b792d-fc2f-440c-9746-b4670250a239
      type: ""
    persistentVolumeReclaimPolicy: Delete
    storageClassName: hostpath
    volumeMode: Filesystem
  status:
    phase: Bound
- apiVersion: v1
  kind: PersistentVolume
  metadata:
    creationTimestamp: "2020-07-13T12:05:28Z"
    finalizers:
    - kubernetes.io/pv-protection
    labels:
      aws-availability-zone: us-east-1
      storage-tier: gold
    name: gluster-volume
    resourceVersion: "201169"
    selfLink: /api/v1/persistentvolumes/gluster-volume
    uid: 12f08ccd-454c-46d0-b2dd-cf5f774b9266
  spec:
    accessModes:
    - ReadWriteMany
    capacity:
      storage: 2Gi
    glusterfs:
      endpoints: glusterfs-cluster
      path: myVol1
    persistentVolumeReclaimPolicy: Retain
    volumeMode: Filesystem
  status:
    phase: Available
kind: List
metadata:
  resourceVersion: ""
  selfLink: ""

根據(jù)輸出的 claimRef來看，我們?cè)O(shè)置的PersistentVolume沒有被使用反而自行設(shè)置了一個(gè)，為什么？

qiantao@qiant k8s %  kubectl get storageclass

NAME                 PROVISIONER          AGE
hostpath (default)   docker.io/hostpath   12d

獲取默認(rèn)的storageclass發(fā)現(xiàn)我們有個(gè)默認(rèn)的hostpath

重點(diǎn)就是，如果我們不設(shè)置storageclass那么k8s會(huì)使用默認(rèn)的storageclass來創(chuàng)建我們需要的PersistentVolume

如何修改默認(rèn)的storageclass參考https://k8smeetup.github.io/docs/tasks/administer-cluster/change-default-storage-class/

關(guān)于StorageClass的詳細(xì)介紹可以參考此處https://kubernetes.io/zh/docs/concepts/storage/storage-classes/

官方文檔說明如下

默認(rèn)行為

可以在群集上啟用動(dòng)態(tài)卷供應(yīng)，以便在未指定存儲(chǔ)類的情況下動(dòng)態(tài)設(shè)置所有聲明。 集群管理員可以通過以下方式啟用此行為：

管理員可以通過向其添加 storageclass.kubernetes.io/is-default-class 注解來將特定的 StorageClass 標(biāo)記為默認(rèn)。 當(dāng)集群中存在默認(rèn)的 StorageClass 并且用戶創(chuàng)建了一個(gè)未指定 storageClassName 的 PersistentVolumeClaim 時(shí)， DefaultStorageClass 準(zhǔn)入控制器會(huì)自動(dòng)向其中添加指向默認(rèn)存儲(chǔ)類的 storageClassName 字段。

請(qǐng)注意，群集上最多只能有一個(gè) 默認(rèn) 存儲(chǔ)類，否則無法創(chuàng)建沒有明確指定 storageClassName 的 PersistentVolumeClaim。

2.PV在Retain策略Released狀態(tài)下重新分配到PVC恢復(fù)數(shù)據(jù)

參考文檔 https://blog.51cto.com/ygqygq2/2308576
問題:
傳出PVC之后出現(xiàn)PV還在還處于占中狀態(tài)，無法重新分配
示例如下：

kind: PersistentVolume
apiVersion: v1
metadata:
  name: chenjunhao1-10-26-133-27-pv-nfs-data
  selfLink: /api/v1/persistentvolumes/chenjunhao1-10-26-133-27-pv-nfs-data
  uid: 75e64e9d-94f6-4bc0-baea-9b89b5fcc7fb
  resourceVersion: '208095'
  creationTimestamp: '2020-07-10T08:48:10Z'
  labels:
    pv: chenjunhao1-10-26-133-27-pv-nfs-data
  annotations:
    pv.kubernetes.io/bound-by-controller: 'yes'
  finalizers:
    - kubernetes.io/pv-protection
spec:
  capacity:
    storage: 200Gi
  nfs:
    server: 10.26.133.27
    path: /home/chenjunhao1
  accessModes:
    - ReadWriteMany
  claimRef:
    kind: PersistentVolumeClaim
    namespace: default
    name: chenjunhao1-10-26-133-27-pvc-nfs-data
    uid: b1be9f21-3fec-49c5-a803-94a30783be86
    apiVersion: v1
    resourceVersion: '123603'
  persistentVolumeReclaimPolicy: Retain
  storageClassName: nfs-data
  volumeMode: Filesystem
status:
  phase: Released

但是對(duì)應(yīng)的PVC已經(jīng)刪除，
這時(shí)候我們可以放心大膽的刪除spec. claimRef字段重新 kubectl apply -f <spec.yaml>
就可以得到

kind: PersistentVolume
apiVersion: v1
metadata:
  name: chenjunhao1-10-26-133-27-pv-nfs-data
  selfLink: /api/v1/persistentvolumes/chenjunhao1-10-26-133-27-pv-nfs-data
  uid: 75e64e9d-94f6-4bc0-baea-9b89b5fcc7fb
  resourceVersion: '208224'
  creationTimestamp: '2020-07-10T08:48:10Z'
  labels:
    pv: chenjunhao1-10-26-133-27-pv-nfs-data
  annotations:
    pv.kubernetes.io/bound-by-controller: 'yes'
  finalizers:
    - kubernetes.io/pv-protection
spec:
  capacity:
    storage: 200Gi
  nfs:
    server: 10.26.133.27
    path: /home/chenjunhao1
  accessModes:
    - ReadWriteMany
  persistentVolumeReclaimPolicy: Retain
  storageClassName: nfs-data
  volumeMode: Filesystem
status:
  phase: Available

故障查詢說明

https://kubernetes.io/zh/docs/tasks/debug-application-cluster/debug-application/

命令路徑

https://kubernetes.io/zh/docs/reference/kubectl/cheatsheet/

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