K8S 部署策略详解-重建、滚动、蓝绿、金丝雀

我们要更细一个服务，都用什么策略呢？

部署策略实践

• Rolling update (滚动更新）
• Recreate (重建），先停止旧的服务，都停掉之后再启动一批新的服务
• 蓝绿部署，利用 service 的 selector，去选择不同版本的服务，
• 金丝雀部署，通过一个ingress 同时去轮询的访问不同的两个后端服务

重建

web-recreate.yaml 文件

#deploy
apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-recreate
  namespace: dev
spec:
  strategy:
    type: Recreate
  selector:
    matchLabels:
      app: web-recreate
  replicas: 2
  template:
    metadata:
      labels:
        app: web-recreate
    spec:
      containers:
      - name: web-recreate
        image: hub.mooc.com/kubernetes/web:v1
        ports:
        - containerPort: 8080
        livenessProbe:
          tcpSocket:
            port: 8080
          initialDelaySeconds: 20
          periodSeconds: 10
          failureThreshold: 2
          successThreshold: 1
          timeoutSeconds: 5
        readinessProbe:
          httpGet:
            path: /examples/index.html
            port: 8080
            scheme: HTTP
          initialDelaySeconds: 10
          periodSeconds: 5
          failureThreshold: 1
          successThreshold: 1
          timeoutSeconds: 5
---
#service
apiVersion: v1
kind: Service
metadata:
  name: web-recreate
  namespace: dev
spec:
  ports:
  - port: 80
    protocol: TCP
    targetPort: 8080
  selector:
    app: web-recreate
  type: ClusterIP

---
#ingress
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: web-recreate
  namespace: dev
spec:
  rules:
  - host: web-recreate.mooc.com
    http:
      paths:
      - path: /
        backend:
          serviceName: web-recreate
          servicePort: 80

部署：

kubectl apply -f web-recreate.yaml

查看运行状态：

[hemei@master 6-deployment]$ kubectl get pods -n dev
NAME                           READY   STATUS    RESTARTS   AGE
web-recreate-65b55f46c-8lbgn   1/1     Running   0          10m
web-recreate-65b55f46c-wphfk   1/1     Running   0          10m
[hemei@master 6-deployment]$ 

修改部署文件，然后再更新

...
spec:
  strategy:
    type: Recreate
  selector:
    matchLabels:
      app: web-recreate
  replicas: 2
  template:
    metadata:
      labels:
        app: web-recreate
       type: webapp
    ...

可以看到先停止服务，然后再重建。

由于资源有限，所以，删掉部署的服务：

[heimei@master 6-deployment]$ kubectl delete -f web-recreate-new.yaml 
deployment.apps "web-recreate" deleted
service "web-recreate" deleted
Warning: extensions/v1beta1 Ingress is deprecated in v1.14+, unavailable in v1.22+; use networking.k8s.io/v1 Ingress
ingress.extensions "web-recreate" deleted
[hemei@master 6-deployment]$ 

[heimei@master 6-deployment]$ kubectl get pods -n dev
No resources found in dev namespace.

可以看到服务已经被删掉了。

滚动更新

web-rollingupdate.yaml

#deploy
apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-rollingupdate
  namespace: dev
spec:
  strategy:
    rollingUpdate:
      maxSurge: 25%
      maxUnavailable: 25%
    type: RollingUpdate
  selector:
    matchLabels:
      app: web-rollingupdate
  replicas: 2
  template:
    metadata:
      labels:
        app: web-rollingupdate
    spec:
      containers:
      - name: web-rollingupdate
        image: hub.mooc.com/kubernetes/web:v1
        ports:
        - containerPort: 8080
        resources:
          requests:
            memory: 1024Mi
            cpu: 500m
          limits:
            memory: 2048Mi
            cpu: 2000m
        livenessProbe:
          tcpSocket:
            port: 8080
          initialDelaySeconds: 20
          periodSeconds: 10
          failureThreshold: 3
          successThreshold: 1
          timeoutSeconds: 5
        readinessProbe:
          httpGet:
            path: /hello?name=test
            port: 8080
            scheme: HTTP
          initialDelaySeconds: 20
          periodSeconds: 10
          failureThreshold: 1
          successThreshold: 1
          timeoutSeconds: 5
---
#service
apiVersion: v1
kind: Service
metadata:
  name: web-rollingupdate
  namespace: dev
spec:
  ports:
  - port: 80
    protocol: TCP
    targetPort: 8080
  selector:
    app: web-rollingupdate
  type: ClusterIP

---
#ingress
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: web-rollingupdate
  namespace: dev
spec:
  rules:
  - host: web-rollingupdate.mooc.com
    http:
      paths:
      - path: /
        backend:
          serviceName: web-rollingupdate
          servicePort: 80

在部署后，会间隔的访问新服务和旧服务。

# 如果部署的有问题，可以再次更新部署
kubectl rollout undo deploy web-rooling.yaml

蓝绿部署

web-bluegreen.yaml

#deploy
apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-bluegreen
  namespace: dev
spec:
  strategy:
    rollingUpdate:
      maxSurge: 25%
      maxUnavailable: 25%
    type: RollingUpdate
  selector:
    matchLabels:
      app: web-bluegreen
  replicas: 2
  template:
    metadata:
      labels:
        app: web-bluegreen
        version: v1.0
    spec:
      containers:
      - name: web-bluegreen
        image: hub.mooc.com/kubernetes/web:v1
        ports:
        - containerPort: 8080
        resources:
          requests:
            memory: 1024Mi
            cpu: 500m
          limits:
            memory: 2048Mi
            cpu: 2000m
        livenessProbe:
          tcpSocket:
            port: 8080
          initialDelaySeconds: 20
          periodSeconds: 10
          failureThreshold: 3
          successThreshold: 1
          timeoutSeconds: 5
        readinessProbe:
          httpGet:
            path: /hello?name=test
            port: 8080
            scheme: HTTP
          initialDelaySeconds: 20
          periodSeconds: 10
          failureThreshold: 1
          successThreshold: 1
          timeoutSeconds: 5

bluegreen-service.yaml

---
#service
apiVersion: v1
kind: Service
metadata:
  name: web-bluegreen
  namespace: dev
spec:
  ports:
  - port: 80
    protocol: TCP
    targetPort: 8080
  selector:
    app: web-bluegreen
    version: v1.0
  type: ClusterIP

---
#ingress
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: web-bluegreen
  namespace: dev
spec:
  rules:
  - host: web-bluegreen.mooc.com
    http:
      paths:
      - path: /
        backend:
          serviceName: web-bluegreen
          servicePort: 80

为者常成，行者常至