4. Pod生命周期管理

4.1 Liveness command

通过命令行实现Liveness检查

# 编写Yaml
apiVersion: v1
kind: Pod
metadata:
  labels:
    test: liveness
  name: liveness-exec
spec:
  containers:
  - name: liveness
    image: radial/busyboxplus
    imagePullPolicy: IfNotPresent
    args:
    - /bin/sh
    - -c
    - touch /tmp/healthy; sleep 60; rm -rf /tmp/healthy; sleep 600
    livenessProbe:
      exec:
        command:
        - cat
        - /tmp/healthy
      initialDelaySeconds: 5
      periodSeconds: 5
      
# 验证方法
kubectl exec -it liveness-exec -- ls /tmp
kubectl get pod

4.2 Liveness HTTP request

通过HTTP Request实现Liveness健康检查

# 编写Yaml文件
apiVersion: v1
kind: Pod
metadata:
  labels:
    test: liveness
  name: liveness-http
spec:
  containers:
  - name: liveness
    image: seedoflife/liveness
    imagePullPolicy: IfNotPresent
    args:
    - /server
    livenessProbe:
      httpGet:
        path: /healthz
        port: 8080
        httpHeaders:
        - name: X-Custom-Header
          value: Awesome
      initialDelaySeconds: 3
      periodSeconds: 3

# 验证方法
curl -v <Pod IP>:<Port>
kubectl get pod

4.3 ReadinessProbe + Service

通过tcpSocket实现ReadInessProbe + Service的健康检查

# 编写Yaml文件
apiVersion: apps/v1
kind: Deployment
metadata:
  name: service-health
spec:
  replicas: 1
  selector:
    matchLabels:
      app: service-health
  template:
    metadata:
      labels:
        app: service-health
    spec:
      containers:
      - name: service-health
        image: python:2.7
        imagePullPolicy: IfNotPresent
        command: ["/bin/bash","-c","echo $(hostname) > index.html && sleep 30 && python -m SimpleHTTPServer 8080"]
        ports:
        - containerPort: 8080
        readinessProbe:
          tcpSocket:
            port: 8080
          initialDelaySeconds: 10
          periodSeconds: 10

# 创建Service
kubectl expose deployment service-health --port=8080
          
# 验证方法
kubectl get service
kubectl scale deployment service-health --replicas=4
curl <ClusterIP>:<Port>