實驗目的

• 判斷Liveness 探測 對副本數(shù)變化
• 判斷Readiness 探測 對副本數(shù)變化
• 判斷Readiness 探測 再次健康時是否從新加入svc

Liveness 實驗

# cat centos.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  creationTimestamp: null
  labels:
    app: centos-test
  name: centos-test
spec:
  replicas: 5
  selector:
    matchLabels:
      app: centos-test
  strategy: {}
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: centos-test
    spec:
      containers:
      - image: centos:7
        name: centos
        args:
        - tail
        - -f
        - /etc/hosts
        livenessProbe:
          httpGet:
            path: /
            port: 80
          initialDelaySeconds: 60
          periodSeconds: 3
          
# kubectl exec -it POD_NAME -- python -m SimpleHTTPServer 80

實驗小結(jié)

副本數(shù)變化沒有任何變化,pod名字也沒有變化.

Readiness 實驗

# cat centos.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  creationTimestamp: null
  labels:
    app: centos-test
  name: centos-test
spec:
  replicas: 5
  selector:
    matchLabels:
      app: centos-test
  strategy: {}
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: centos-test
    spec:
      containers:
      - image: centos:7
        name: centos
        args:
        - tail
        - -f
        - /etc/hosts
        readinessProbe:
          httpGet:
            path: /
            port: 80
          initialDelaySeconds: 60
          periodSeconds: 3
---
apiVersion: v1
kind: Service
metadata:
  creationTimestamp: null
  labels:
    app: centos-test
  name: centos-svc
spec:
  ports:
  - port: 80
    protocol: TCP
    targetPort: 80
  selector:
    app: centos-test
  type: NodePort
  
# kubectl exec -it POD_NAME -- python -m SimpleHTTPServer 80

實驗小結(jié)

副本數(shù)變化沒有任何變化,健康狀態(tài)下ep可以掛載Pod IP
健康健康,不健康從ep摘除,健康從ep掛載

整體總結(jié)

• Liveness 探測 用于應用本身導致的錯誤重啟可以快速解決
• Readiness 探測 用于自身是否可以正常接收流量，和非本身問題導致的錯誤，等待后端問題解決就可以恢復