pod生命周期:
状态:pending 挂起
没有节点满足条件
running 运行
Failed
sucess
unkonwn
pod生命周期中的重要行为：
初始化容器
容器探测：liveness probe 探测容器是否活着 探测容器 存活性探针
readindess probe 探测容器中主程序是否正常提供服务 就绪性探针
restartPolicy:容器重启策略
Always,OnFailure,Never,Default to always
pod终止过程:发送指令给容器并有等待机制
查看liveness, readindess
kubectl explain pods.spec.containers
探针类型有三种：探测容器
ExecAction:
TCPSocketAction:套接字探针
HTTPGetAction:
liveness Probe探测情况
kubectl explain pods.spec.containers.livenessProbe
例如
kubectl explain pods.spec.containers.livenessProbe.exec
liveness Probe探针类型:三种只用其中一种
exec <Object>
tcpSocket <Object>
httpGet <Object>
附加属性
failureThreshold <integer> 探测几次失败，才认为失败
periodSeconds <integer> 探测间隔时间 单位秒
timeoutSeconds <integer> 每次探测超时时间响应
initialDelaySeconds <integer> 容器初始化后延迟的探测时间,容器第一次探测时间 默认容器一启动就开始探测
readinessProbe就绪行探测的属性与livenessProbe一样
kubectl explain pods.spec.containers.readinessProbe
livenessProbe实例：
exec<Object>
kubectl explain pods.spec.containers.livenessProbe.exec
实例:
vim leveness-exec.yaml
apiVersion: v1
kind: Pod
metadata:
name: liveness-exec-pod
namespace: default
spec:
containers:
- name: liveness-exec-container
image: busybox:latest
imagePullPolicy: IfNotPresent
command: ["/bin/sh","-c","touch /tmp/healthy;sleep 30;rm -f /tmp/healthy;sleep 3600"] 容器初始化命令
livenessProbe:
exec: exec探针 执行
command: ["test","-e","/tmp/healthy"] 探测命令 返回true false 返回false的话restartPolicy容器重启策略执行 restart
initialDelaySeconds: 2 容器初始化后2秒探测
periodSeconds: 3 探针返回true 间隔3秒再探测
kubectl create -f leveness-exec.yaml
kubectl get pods –w
kubectl describe pods liveness-exec-pod
livenessProbe
tcpSocket探针
kubectl explain pods.spec.containers.livenessProbe.tcpSocket
livenessProbe
httpGet探针
kubectl explain pods.spec.containers.livenessProbe.httpGet
实例:
cp leveness-exec.yaml liveness-httpdget.yaml
vim liveness-httpdget.yaml
apiVersion: v1
kind: Pod
metadata:
name: liveness-httpget-pod
namespace: default
spec:
containers:
- name: liveness-httpget-container
image: ikubernetes/myapp:v1
imagePullPolicy: IfNotPresent
ports:
- name: http
containerPort: 80
livenessProbe:
httpGet: 探针
port: http port的name
path: /index.html 请求的网页 网页请求不到,restartPolicy重启策略执行restart，重启之后 容器文件会重置
initialDelaySeconds: 1 容器初始化1秒后探测
periodSeconds: 3 间隔3秒探测
kubectl create -f liveness-httpdget.yaml
kubectl get pods –w
kubectl describe pods liveness-httpget-pod
查看Liveness:结果
实验过程：
kubectl exec -it liveness-httpget-pod -- /bin/sh 进入容器
rm -rf /usr/share/nginx/html/index.html
kubectl describe pods liveness-httpget-pod 显示 restart count
就绪性探测实例：
cp liveness-httpdget.yaml readiness-httpget.yaml
vim readiness-httpget.yaml
apiVersion: v1
kind: Pod
metadata:
name: readiness-httpget-pod
namespace: default
spec:
containers:
- name: readiness-httpget-container
image: ikubernetes/myapp:v1
imagePullPolicy: IfNotPresent
ports:
- name: http
containerPort: 80
readinessProbe:
httpGet:
port: http
path: /index.html 能够访问就会显示就绪 ready 1，访问不到就会显示不就绪 ready为0
initialDelaySeconds: 1
periodSeconds: 3
kubectl create -f readiness-httpget.yaml
kubectl get pods
实验过程
kubectl exec -it readiness-httpget-pod -- /bin/sh
rm -rf /usr/share/nginx/html/index.html
kubectl get pods
kubectl get pods 此时显示ready状态为0
kubectl exec -it readiness-httpget-pod -- /bin/sh
touch /usr/share/nginx/html/index.html
kubectl get pods 此时ready为1 因为已经能够探测到了
kubectl describe pods readiness-httpget-pod 查看Readiness
容器启动后勾子,结束前勾子
kubectl explain pods.spec.containers.lifecycle
postStart <Object>
kubectl explain pods.spec.containers.lifecycle.postStart
实例:
vim poststart-pod.yaml
apiVersion: v1
kind: Pod
metadata:
name: poststart-pod
namespace: default
spec:
containers:
- name: busybox-httpd
image: busybox:latest
imagePullPolicy: IfNotPresent
lifecycle:
postStart:
exec:
command: ["/bin/sh","-c","mkdir -p /data/web/html;echo Home_Page>> /data/web/html/index.html"] 容器初始化后执行
command: ["/bin/sh",”-c”,”sleep 3600”] 容器启动 时执行 既容器初始化前就已经执行 先执行
kubectl create -f poststart-pod.yaml
kubectl get pods
登录检查勾子执行的结果
kubectl exec -it poststart-pod -- /bin/sh
ls /data/web/html/
cat /data/web/html/index.html
preStop <Object>
kubectl explain pods.spec.containers.lifecycle.preStop
注释：/bin/httpd -f -h /data/web/html
在前台执行 指定家目录