k8s資源之statefulset

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​​不懂envoyfilter也敢說精通istio系列-02-http-corsFilter-不要隻會vs​​

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statefulset:

StatefulSet是Kubernetes提供的管理有狀态應用的負載管理控制器API。

特點：

1.具有固定的網絡标記（主機名）

2.具有持久化存儲

3.需要按順序部署和擴充

4.需要按順序終止和删除

5.需要按順序滾動和更新

Headless service:

•在Deployment中，與之對應的服務是service，而在StatefulSet中與之對應的headless service

•StatefulSet在Headless Service的基礎上又為StatefulSet控制的每個Pod副本建立了一個DNS域名，這個域名的格式為：

$(podname).(headless server name)

FQDN： $(podname).(headless server name).namespace.svc.cluster.local

示例:

apiVersion: v1
kind: Service
metadata:
 name: nginx
 labels:
  app: nginx
spec:
 ports:
 - port: 80
   name: web
 clusterIP: None
 selector:
  app: nginx
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
 name: web
spec:
 serviceName: "nginx"
 replicas: 2
 selector:
  matchLabels:
   app: nginx
 template:
  metadata:
   labels:
    app: nginx
  spec:
   containers:
   - name: nginx
     image: nginx
     ports:
     - containerPort: 80
       name: web      

yum -y install rpcbind nfs-utils
vim /etc/exports
/nfs 192.168.198.0/24(rw,no_root_squash,no_all_squash,sync)
exportfs  -rv
systemctl start rpcbind systemctl start nfs 
mount  -t nfs 192.168.198.156:/nfs /mnt

apiVersion: v1
kind: Service
metadata:
  name: nginx
  labels:
    app: nginx
spec:
  ports:
  - port: 80
    name: web
  clusterIP: None
  selector:
    app: nginx
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: web
spec:
  selector:
    matchLabels:
      app: nginx
  serviceName: "nginx"
  replicas: 3
  template:
    metadata:
      labels:
        app: nginx
    spec:
      terminationGracePeriodSeconds: 10
      containers:
      - name: nginx
        image: nginx
        ports:
        - containerPort: 80
          name: web
        volumeMounts:
        - name: www
          mountPath: /usr/share/nginx/html
  volumeClaimTemplates:
  - metadata:
      name: www
    spec:
      accessModes: [ "ReadWriteOnce" ]
      storageClassName: "nfs-sc"
      resources:
        requests:
          storage: 10Mi      

為什麼需要 headless service 無頭服務？:

•pod IP是變化的，是以是以Pod名稱來識别。pod名稱是pod唯一性的辨別符，必須持久穩定有效。這時候要用到無頭服務，它可以給每個Pod一個唯一的名稱 。

為什麼需要volumeClaimTemplate:

•statefulset的存儲卷就不能再用Pod模闆來建立了，于是statefulSet使用volumeClaimTemplate，稱為卷申請模闆，它會為每個Pod生成不同的pvc，并綁定pv， 進而實作各pod有專用存儲

podManagementPolicy:

apiVersion: v1
kind: Service
metadata:
 name: nginx
 labels:
  app: nginx
spec:
 ports:
 - port: 80
   name: web
 clusterIP: None
 selector:
  app: nginx
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
 name: web
spec:
 podManagementPolicy: Parallel  
 serviceName: "nginx"
 replicas: 2
 selector:
  matchLabels:
   app: nginx
 template:
  metadata:
   labels:
    app: nginx
  spec:
   containers:
   - name: nginx
     image: nginx
     ports:
     - containerPort: 80
       name: web      

updateStrategy:

apiVersion: v1
kind: Service
metadata:
 name: nginx
 labels:
  app: nginx
spec:
 ports:
 - port: 80
   name: web
 clusterIP: None
 selector:
  app: nginx
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
 name: web
spec:
 updateStrategy:
   type: OnDelete
 serviceName: "nginx"
 replicas: 2
 selector:
  matchLabels:
   app: nginx
 template:
  metadata:
   labels:
    app: nginx
  spec:
   containers:
   - name: nginx
     image: nginx
     ports:
     - containerPort: 80
       name: web      

partition:

apiVersion: v1
kind: Service
metadata:
 name: nginx
 labels:
  app: nginx
spec:
 ports:
 - port: 80
   name: web
 clusterIP: None
 selector:
  app: nginx
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
 name: web
spec:
 updateStrategy:
   type: RollingUpdate
   rollingUpdate:
     partition: 5
 serviceName: "nginx"
 replicas: 2
 selector:
  matchLabels:
   app: nginx
 template:
  metadata:
   labels:
    app: nginx
  spec:
   containers:
   - name: nginx
     image: nginx
     ports:
     - containerPort: 80
       name: web      

QoS:

apiVersion: v1
kind: Service
metadata:
 name: nginx
 labels:
  app: nginx
spec:
 ports:
 - port: 80
   name: web
 clusterIP: None
 selector:
  app: nginx
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
 name: web
spec:
 serviceName: "nginx"
 replicas: 2
 selector:
  matchLabels:
   app: nginx
 template:
  metadata:
   labels:
    app: nginx
  spec:
   containers:
   - name: nginx
     image: nginx
     ports:
     - containerPort: 80
       name: web
     resources:
       requests:
         cpu: 0.01
         memory: 20Mi
       limits:
         cpu: 0.01
         memory: 20Mi      

apiVersion: v1
kind: Service
metadata:
 name: nginx
 labels:
  app: nginx
spec:
 ports:
 - port: 80
   name: web
 clusterIP: None
 selector:
  app: nginx
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
 name: web
spec:
 serviceName: "nginx"
 replicas: 2
 selector:
  matchLabels:
   app: nginx
 template:
  metadata:
   labels:
    app: nginx
  spec:
   containers:
   - name: nginx
     image: nginx
     ports:
     - containerPort: 80
       name: web
     resources:
       requests:
         cpu: 0.01
         memory: 20Mi      

apiVersion: v1
kind: Service
metadata:
 name: nginx
 labels:
  app: nginx
spec:
 ports:
 - port: 80
   name: web
 clusterIP: None
 selector:
  app: nginx
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
 name: web
spec:
 serviceName: "nginx"
 replicas: 2
 selector:
  matchLabels:
   app: nginx
 template:
  metadata:
   labels:
    app: nginx
  spec:
   containers:
   - name: nginx
     image: nginx
     ports:
     - containerPort: 80
       name: web
     resources:
       requests:
         cpu: 0.01
         memory: 20Mi
       limits:
         cpu: 0.01
         memory: 40Mi      

apiVersion: v1
kind: Service
metadata:
 name: nginx
 labels:
  app: nginx
spec:
 ports:
 - port: 80
   name: web
 clusterIP: None
 selector:
  app: nginx
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
 name: web
spec:
 serviceName: "nginx"
 replicas: 2
 selector:
  matchLabels:
   app: nginx
 template:
  metadata:
   labels:
    app: nginx
  spec:
   containers:
   - name: nginx
     image: nginx
     ports:
     - containerPort: 80
       name: web