10-kubernetes statefulset控制器

有状态副本集控制器，需要关注个体，无状态关注群体，坏一个替换即可

管理具有一下特性的程序

稳定且唯一的网络标识符
稳定且持久的存储
有序，平滑地部署和扩展
有序，平滑地删除和终止
有序的滚动更新

典型Statefulset有三组件组成

Headless Hervice(无头服务)
Statefulset （控制器）
volumeClaimTemplate (存储卷申请模板)

POD标识符需要稳定持久有效且唯一名称，每个节点需要有专有的存储

部署例子：

前期准备好存储，配置好，PV 与PVC

1.定义 PV

kubectl explain pv.spec.nfs   #帮助信息。

NFS 配置PV例子

apiVersion: v1                                                                                                                                                                                                    
kind: PersistentVolume
metadata:
  name: pv001
  labels:
    name: pv001
spec:
  nfs:
    path: /data/volumes/v1
    server: stor01.leiyan.com
  accessModes: ["ReadWriteMany","ReadWriteOnce"]
  capacity:
    storage: 5Gi
---

apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv002
  labels:
    name: pv002
spec:
  nfs:
    path: /data/volumes/v2
    server: stor01.leiyan.com
  accessModes: ["ReadWriteOnce"]
  capacity:
    storage: 5Gi
---

apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv003
  labels:
    name: pv003
spec:
  nfs:
    path: /data/volumes/v3
    server: stor01.leiyan.com
  accessModes: ["ReadWriteMany","ReadWriteOnce"]
  capacity:
    storage: 5Gi

---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv004
  labels:
    name: pv004
spec:
  nfs:
    path: /data/volumes/v4
    server: stor01.leiyan.com
  accessModes: ["ReadWriteMany","ReadWriteOnce"]
  capacity:
    storage: 10Gi
---

apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv005
  labels:
    name: pv005
spec:
  nfs:
    path: /data/volumes/v5
    server: stor01.leiyan.com
  accessModes: ["ReadWriteMany","ReadWriteOnce"]
  capacity:
    storage: 10Gi

配置StatefulSet例子

apiVersion: v1                                                                                                                    
kind: Service
metadata:
  name: myapp-svc
  labels:
      app: myapp-svc
spec:
  ports: 
  - port: 80
    name: web
  clusterIP: None
  selector:
    app: myapp-pod
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: myapp
spec:
  serviceName: myapp-svc
  replicas: 3
  selector:
    matchLabels:
      app: myapp-pod
  template:
    metadata:
      labels:
        app: myapp-pod
    spec:
      containers:
      - name: myapp
        image: ikubernetes/myapp:v1
        ports:
        - containerPort: 80
          name: web
        volumeMounts:
        - name: myappdata
          mountPath: /usr/share/ngin/html
  volumeClaimTemplates:
  - metadata:
      name: myappdata
    spec:
      accessModes: ["ReadWriteOnce"]
      storageClassName: "gluster-dynamic"  
      resources:
          requests:
            storage: 5Gi

验证

kubectl get svc
kubectl get sts
kubectl get pvc

#解析格式
POD_NAME.SERVICE_NAME.NS_NAME.svc.cluster.local
myapp-0.myapp.default.svc.cluster.local

扩缩容

kubectl scale sts myapp --relicas=5
kubectl patch sts myapp -p '{"spec":{"replicas":5}}'

升级

kubectl explain sts.spec.updateStrategy.rollingUpdate

#分区更新方法
partition:N
    >=4 

kubectl patch sts myapp -p '{"spec":{"updateStrategy":{"rollingUpdate":{"partition":4}}}}'

#开始更新第0个开始的容器
kubectl patch sts myapp -p '{"spec":{"template":{"spec":{"containers[0]":{"image":"ikubernetes/myapp:v2"}}}}}'

#或者
kubectl set image sts/myapp myapp=ikubernetes/myapp:v2

#验证
kubectl get sts -o wide
kubectl get pods -o wide
kubectl get pods myapp-3 -o yaml