Kubernetes探针检测

探针分为两种类型：

1. readinessProbe：判断容器是否准备好服务请求，初始延迟之前的就绪状态默认为Failure，如果容器不提供就绪探针，则默认状态为Success；
2. livenessProbe：指示容器是否运行，如果探测失败kubelet则会杀死该Pod，并且容器将会受到重启策略的影响。

 探针的三种检测方法：

1. ExecAction：在容器内执行指定命令，如果命令退出时的状态码为0，则判断 为诊断成功；
2. TCPSockeAction：对指定端口上的IP地址进行TCP检查，如果端口打开，则被诊断为成功；
3. HTTPGetAction：对指定端口和路径上的容器IP执行HTTP Get请求，如果响应的状态码大于等于200且小于400，则为诊断成功。

例子：

readlinessProbe-httpget

apiVersion: v1
kind: Pod
metadata:
  name: nginx-test
  namespace: nginx
spec:
  containers:
    - name: nginx
      image: ntp.wei.club/nginx:v1
      imagePullPolicy: IfNotPresent
      readinessProbe:                        #定义为readinessProbe
        httpGet:
          port: 80                           #检测80端口也可写为http
          path: /index1.html                 #检测路径为/index1.html
        initialDelaySeconds: 1               #容器启动后1秒进行检测
        periodSeconds: 3                     #检测周期为3秒间隔

livenessProbe-exec

apiVersion： v1
kind: Pod
metadata:
  name: nginx_test
  namespace: nginx
spce:
  containers:
  - name: nginx
    image: ntp.weij.club/nginx:v1
    imagePullPolicay
    ports:
    - containerport: 80
    command: ["/bin/sh","-c","touch /tmp/live;sleep 10"]
    livenessProbe:
      exec:
        command: ["test","-e","/tmp/live"]
      initialDelaySeconds: 1
      periodSeconds: 3

livenessPorbe-httpget

apiVersion: v1
kind: Pod
metadata:
  name: nginx-test
  namespace: nginx
spce:
  containers:
  - name: nginx
    image: ntp.weij.club/nginx:v1
    imagePullPolicy: IfNotPresent
    ports:
    - name: http
      containerPort: 80
    livenessProbe:
      httpGet:
        port: 80
        path: /index.html
      initialDelaySeconds: 1
      periodSeconds: 3
      timeoutSeconds: 10                            #指定超时时间即为检测失败

livenessProbe-tcpsocket

apiVersion: v1
kind: Pod
metadata:
  name: nginx-test
  namespace: nginx
spec:
  containers:
  - name: nginx
    image: ntp.weij.club/nginx:v1
    imagePullPolicy: IfNotPresent
    ports:
    - name: nginx
      containerPort: 80
    livenessProbe:
      tcpSocket:
        port: 80
      initiaDelaySeconds: 1
      periodSeconds: 3
      timeoutSeconds: 5

注：livenessPorbe可以和readlinessProbe结合，也可以存在多个livenessProbe只需格式写的相对应