一、Nfs動態分配pv

有兩種PV提供的方式：靜態和動態，
靜態PV：集群管理員創建多個PV，它們攜帶著真實存盤的詳細資訊，這些存盤對于集群用戶是可用的，它們存在于Kubernetes API中，并可用于存盤使用，
動態PV：當管理員創建的靜態PV都不匹配用戶的PVC時，集群可能會嘗試專門地供給volume給PVC，這種供給基于StorageClass，

StorageClass提供了一種描述存盤類（class）的方法，不同的class可能會映射到不同的服務質量等級和備份策略或其他策略等，

每個 StorageClass 都包含 provisioner、parameters 和 reclaimPolicy 欄位， 這些欄位會在StorageClass需要動態分配 PersistentVolume 時會使用到，

自動創建PV和對應的PVC，本身不提供NFS存盤，需要外部先有一套NFS存盤服務，所以本章操作是基于實驗環境中nfs已部署完成才進行的，

創建操作目錄并進入，將檔案移入

mkdir nfs-client
cd nfs-client/
cp ~/nfs-client-provisioner.yaml .

編輯資源清單，參考官網：https://github.com/kubernetes-incubator/external-storage/tree/master/nfs-client

vim nfs-client-provisioner.yaml

apiVersion: v1
kind: ServiceAccount
metadata:
  name: nfs-client-provisioner
  # replace with namespace where provisioner is deployed
  namespace: nfs-client-provisioner
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: nfs-client-provisioner-runner
rules:
  - apiGroups: [""]
    resources: ["nodes"]
    verbs: ["get", "list", "watch"]
  - 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
    # replace with namespace where provisioner is deployed
    namespace: nfs-client-provisioner
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
  # replace with namespace where provisioner is deployed
  namespace: nfs-client-provisioner
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
  # replace with namespace where provisioner is deployed
  namespace: nfs-client-provisioner
subjects:
  - kind: ServiceAccount
    name: nfs-client-provisioner
    # replace with namespace where provisioner is deployed
    namespace: nfs-client-provisioner
roleRef:
  kind: Role
  name: leader-locking-nfs-client-provisioner
  apiGroup: rbac.authorization.k8s.io
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nfs-client-provisioner
  labels:
    app: nfs-client-provisioner
  # replace with namespace where provisioner is deployed
  namespace: nfs-client-provisioner
spec:
  replicas: 1
  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: nfs-subdir-external-provisioner:v4.0.0
          volumeMounts:
            - name: nfs-client-root
              mountPath: /persistentvolumes
          env:
            - name: PROVISIONER_NAME
              value: westos.org/nfs
            - name: NFS_SERVER
              value: 172.25.9.1 #指定nfs server主機
            - name: NFS_PATH
              value: /mnt/nfs #指定nfs共享路徑
      volumes:
        - name: nfs-client-root
          nfs:
            server: 172.25.9.1 #同上
            path: /mnt/nfs
---
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: managed-nfs-storage
provisioner: westos.org/nfs
parameters:
  archiveOnDelete: "true" #true為洗掉后自動打包備份，false為洗掉后不打包

拉起清單前，先創建好storageclass，準備好鏡像

創建sc，拉起清單

kubectl create namespace nfs-client-provisioner
kubectl apply -f nfs-client-provisioner.yaml
kubectl get sc

創建pvc

vim test-pvc.yaml

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: nfs-pv1
  annotations:
    volume.beta.kubernetes.io/storage-class: "managed-nfs-storage"
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 100Mi

查看創建好的pv和pvc狀態，顯示Bound

kubectl apply -f test-pvc.yaml
kubectl get pvc
kubectl get pv

Delete表示洗掉pvc后 pv也會洗掉，同時檔案會打包
測驗：

首先查看掛載目錄中的檔案

洗掉識訓清單，可以看到pv和pvc均已經洗掉

kubectl delete -f test-pvc.yaml
kubectl get pvc
kubectl get pv

再次查看掛載目錄，檔案已被打包，

測驗完畢，拉起pvc

kubectl apply -f test-pvc.yaml

創建pod節點test-pd

vim pod.yaml
cat pod.yaml

apiVersion: v1
kind: Pod
metadata:
  name: test-pd
spec:
  containers:
  - image: nginx
    name: nginx
    volumeMounts:
    - mountPath: /usr/share/nginx/html
      name: pv1
  volumes:
  - name: pv1
    persistentVolumeClaim:
      claimName: nfs-pv1

需要注意的是，選取pvc名稱需與之前創建的pvc名稱一致，

拉起pod

kubectl apply -f pod.yaml

初次訪問報錯403，原因是默認發布檔案被覆寫

kubectl get pod -o wide
curl 10.244.141.237

添加測驗頁，再次測驗，訪問成功

kubectl get pod -o wide
curl 10.244.141.237

編輯資源清單nfs-client-provisioner.yaml，關閉洗掉后打包，洗掉pvc后檔案會消失

vim nfs-client-provisioner.yaml

parameters:
  archiveOnDelete: "false"

想要檔案更新修改內容，必須洗掉sc后再次生成

kubectl delete sc managed-nfs-storage
kubectl apply -f nfs-client-provisioner.yaml
kubectl get sc

洗掉pvc或pod節點

kubectl delete -f test-pvc.yaml

洗掉太慢可以之間洗掉節點

kubectl delete pod test-pd
kubectl get pvc
kubectl get pv

進入共享目錄下查看

默認的 StorageClass 將被用于動態的為沒有特定 storage class 需求的PersistentVolumeClaims 配置存盤

為pvc設定默認sc狀態

編輯pvc檔案，不特指sc
vim test-pvc.yaml
cat test-pvc.yaml

apiVersion: v1
metadata:
  name: nfs-pv1
spec:
  #storageClassName: managed-nfs-storage
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 100Mi

設定默認storageclass

 kubectl patch storageclass managed-nfs-storage -p '{"metadata": {"annotations":{"storageclass.kubernetes.io/is-default-class":"true"}}}'

拉起清單，查看sc

kubectl apply -f test-pvc.yaml
kubectl get sc

二、StatefulSet如何通過Headless Service維持Pod的拓撲狀態

創建作業目錄并進入

mkdir statefulset
cd statefulset/

編輯資源清單，創建服務nginx
vim nginx-svc.yaml

apiVersion: v1
kind: Service
metadata:
 name: nginx-svc
 labels:
  app: nginx
spec:
 ports:
 - port: 80
   name: web
 clusterIP: None
 selector:
  app: nginx

拉起并查看服務

kubectl apply -f nginx-svc.yaml
kubectl get svc

此時服務還沒有后端endpoint

kubectl describe svc nginx-svc

編輯資源清單創建StatefulSet，設定初始副本數為二個
vim statefulset.yaml

apiVersion: apps/v1
kind: StatefulSet
metadata:
 name: web
spec:
 serviceName: "nginx-svc"
 replicas: 2
 selector:
  matchLabels:
   app: nginx
 template:
  metadata:
   labels:
    app: nginx
  spec:
   containers:
   - name: nginx
     image: myapp:v1
     ports:
     - containerPort: 80
       name: web

拉起容器，查看pod

kubectl apply -f statefulset.yaml

擴容pv，只需將清黨副本數改為6

vim statefulset.yaml

```yaml
apiVersion: apps/v1
kind: StatefulSet
metadata:
 name: web
spec:
 serviceName: "nginx-svc"
 replicas: 3
 selector:
  matchLabels:
   app: nginx
 template:
  metadata:
   labels:
    app: nginx
  spec:
   containers:
   - name: nginx
     image: myapp:v1
     ports:
     - containerPort: 80
       name: web
     volumeMounts:
       - name: www
         mountPath: /usr/share/nginx/html
 volumeClaimTemplates:
  - metadata:
     name: www
    spec:
     #storageClassName: nfs
     accessModes:
     - ReadWriteOnce
     resources:
      requests:
       storage: 1Gi

拉起容器并查看

kubectl get pod

測驗采用三個副本數，恢復副本數到3

vim statefulset.yaml

kubectl apply -f statefulset.yaml

查看節點健康狀況

kubectl get pod

進入容器 ，訪問查看
進入容器，測驗訪問

kubectl run demo --image=busyboxplus -it

kubectl attach demo -it

將pvc與pod節點結合

創建測驗index.html，進入/mnt/nfs各目錄中

 echo web-0 > index.html

echo web-1 > index.html

echo web-2 > index.html

進入容器查看修改內容

kubectl attach demo -it

訪問查看是否負載均衡

curl nginx-svc

洗掉副本后重新拉起，可繼續保留之前的內容

vim statefulset.yaml

將副本改為0即視為洗掉

kubectl apply -f statefulset.yaml

節點正在逐個回收

重新拉起三個副本

進入容器測驗：
依舊負載均衡