k8s 存活探针（健康检查）

重启策略 （RestartPolicy ）

Always：当容器终止退出后，总是重启容器，默认策略。

OnFailure：当容器异常退出（退出状态码非0）时，才重启容器。

Never：当容器终止退出，从不重启容器。

 

probe有以下两种类型：

livenessProbe：如果检查失败，将杀死容器，根据Pod的restartPolicy来操作。

readinessProbe： 如果检查失败，Kubernetes会把Pod从service endpoints中剔除

 

Probe支持以下三种检查方法：

httpGet：发送HTTP请求，返回200-400范围状态码为成功。

exec：执行Shell命令返回状态码是0为成功。

tcpSocket：发起TCP Socket建立成功。

 

 

方法一 httpGet

nginx使用httpGet健康检查的方法

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx
  minReadySeconds: 1
  progressDeadlineSeconds: 60
  revisionHistoryLimit: 2
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 1
  template:
    metadata:
      name: nginx
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.19
        ports:
        - containerPort: 80
        resources:
          requests:
            memory: "500Mi"
            cpu: "250m"
          limits: 
            memory: "500Mi" 
            cpu: "500m"
        livenessProbe:
           httpGet:
             path: /
             port: 80
           initialDelaySeconds: 10  #pod启动10秒执行第一次检查
           periodSeconds: 5         #第一次检查后每隔5秒检查一次
        volumeMounts:
        - name: html
          mountPath: /usr/share/nginx/html
      volumes:
      - name: html
        hostPath:
          path: /home/k8s/data/nginx
---
apiVersion: v1
kind: Service
metadata:
  name: nginx
spec:
  type: NodePort
  ports:
   - port: 8080
     nodePort: 30080
  selector:
    app: nginx

 

方法二：tcpSocket

nginx使用tcpSocket健康检查的方法

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx
  minReadySeconds: 1
  progressDeadlineSeconds: 60
  revisionHistoryLimit: 2
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 1
  template:
    metadata:
      name: nginx
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.19
        ports:
        - containerPort: 80
        resources:
          requests:
            memory: "500Mi"
            cpu: "250m"
          limits: 
            memory: "500Mi" 
            cpu: "500m"
        livenessProbe:
           tcpSocket:
             port: 80
           initialDelaySeconds: 10
           periodSeconds: 5
        volumeMounts:
        - name: html
          mountPath: /usr/share/nginx/html
      volumes:
      - name: html
        hostPath:
          path: /home/k8s/data/nginx
---
apiVersion: v1
kind: Service
metadata:
  name: nginx
spec:
  type: NodePort
  ports:
   - port: 8080
     nodePort: 30080
  selector:
    app: nginx