kubernetes资源清单之Pod应用

# kubectl explain pod.spec.containers
spec.containers <[]object>

- name <string>
  image <string>
  imagePullPolicy: <string>  
  #如果标签是latest则默认值是Always，如果是其他标签则默认值是IfNotPresent
    Always：总是去仓库下载，latest标签的镜像用
    Never：本地有就用，没有就不用
    IfNotPresent：本地有用本地的，本地没有去仓库下载

  ports:  - name: http    containerPort: 80  - name: https    containerPort: 443

metadata:
  name: pod-demo
  namespace: default
  labels:
    app: myapp
    tier: frontend

# kubectl get pods --show-labels  
#查看所有pod的标签
# kubectl get pods --show-labels -L app 
 #显示拥有app标签的值
# kubectl get pods --show-labels -L app,run  
#显示多个标签的标签值
# kubectl get pods --show-labels -l app  
#过滤拥有app标签的pod
# kubectl get pods --show-labels -l app=myapp  
#基于等值的标签选择器（=, ==, !=）
# kubectl get pods --show-labels -l "app in (myapp,noapp)"  
#基于集合关系的标签选择器（in, ontin）

# kubectl label pods pod-demo release=canary  
#给pod打标
# kubectl label pods pod-demo release=stable --overwrite  
#修改标签的值

node标签

# kubectl get nodes --show-labels  
#基于nodeSelector节点选择器
# kubectl label node node01 disktype=ssd  
#给node01增加disktype=ssd的标签

spec:
  nodeSelector:  #使其pod只能运行在拥有disktype=ssd标签的node上
    disktype: ssd

spec:
  nodeName: node01  #使其pod只能运行在node01上

metadata:
  annotations:
    dongfei.tech/created-by: "cluster admin"

# kubectl describe pods pod-demo |grep Annotations

spec:
  restartPolicy:
    Always：默认，总是重启
    OnFailure：Pod失败则会重启
    Never：不会重启

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 10; rm -rf /tmp/healthy; sleep 3600"]
    livenessProbe:
      exec:
        command: ["test","-e","/tmp/healthy"]  #探测命令
      initialDelaySeconds: 1  #初始化延迟时间，默认0s
      periodSeconds: 3  #隔多长时间探测一次，默认10s
      failureThreshold: 3  #探测失败3次为失败，默认3次
      successThreshold: 1  #探测成功1次为成功
  restartPolicy: Always  #探测失败时的重启策略
# kubectl get pods -w  #监控POD状态
# kubectl describe pods liveness-exec-pod |grep "Restart Count"  #查看Pod重启次数

apiVersion: v1
kind: Pod
metadata:
  name: liveness-httpget-pod
  namespace: default
spec:
  containers:
  - name: liveness-httpget-container
    image: dongfeimg/myapp:v1
    imagePullPolicy: IfNotPresent
    ports:
    - name: http
      containerPort: 80
    livenessProbe:
      httpGet:
        port: http
        path: /index.html
      initialDelaySeconds: 1
      periodSeconds: 3
# kubectl exec -it liveness-httpget-pod -- /bin/sh  #手动连入pod
/ # rm -f /usr/share/nginx/html/index.html  #删除index.html文件，探测失败会重启

apiVersion: v1
kind: Pod
metadata:
  name: readiness-httpget-pod
  namespace: default
spec:
  containers:
  - name: readiness-httpget-container
    image: dongfeimg/myapp:v1
    imagePullPolicy: IfNotPresent
    ports:
    - name: http
      containerPort: 80
    readinessProbe:
      httpGet:
        port: http
        path: /index.html
      initialDelaySeconds: 1
      periodSeconds: 3

apiVersion: v1
kind: Pod
metadata:
  name: poststart-pod
  namespace: default
spec:
  containers:
  - name: busybox-httpd
    image: busybox:latest
    imagePullPolicy: IfNotPresent
    lifecycle:
      postStart:
        exec:
          command: ["mkdir","-p","/data/web/html"]  #在command命令后执行此命令
    command: ["/bin/sh","-c","sleep 3600"]