kubenetes入门学习-六-Pod控制器应用进阶

水深无声 2022-03-12 02:43 283阅读 0赞

原理听着好累，加油！

Pod控制器应用进阶  
   资源格式清单格式：  
      一级字段：apiVersion（group/version）,kind(资源类别),metadata(name,namespace,labels,annotations,.....),spec,status(只读)  
        
  kubectl explain pods.spec.containers    
  kubectl explain pods.spec.containers.ports  
  Pod资源：  
      spec.container <\[\]object>  
      - name <string>  
        image <stting>         镜像来源  
        imagePullPolicy <string>  
           Always, Never, IfNotPresent  
        ports <\[\]Object>  
        修改镜像中的默认应用：  
        command, args   
        https://kubernetes.io/docs/tasks/inject-data-application/define-command-argument-container/      
        标签：  
           key=value  
              key：字母、数字 \_ - .       
              value: 可以为空，只能字母或者数字开头或者结尾，中间可使用

一个资源对象上可以有多个标签，一个标签也可以添加到多个资源对象上

k8s两种标签选择器：  
        等值关系  = == !=  
        集合关系    
           KEY in (VALUE1,VALUE2,....)  
           KEY notin (VALUE1,VALUE2,....)  
           KEY   
           !key

许多资源支持内嵌字段定义其使用的标签选择器  
     matchLabels:直接给定键值  
     matchExpression:基于给定的表达式来定义使用的标签选择器，｛key: "KEY", operator: "OPERTOR", values: \[VAL1,VAL2,...\]｝  
        操作符：  
           In,NotIn： values字段的值必须为非空列表；  
           Exists,NotExists：values字段的值必须为空列表；  
nodeSelector  <map\[string\]string>  
     节点标签选择器  
      nodeSelector：  
      disktype: ssd   指定标签选择主机  
        
nodeName <string>

annotations:  
    与labels不同的地方在于，它不能用于挑选资源对象，仅用于为对象提供元数据。

Pod生命周期  
     状态：Pending，Running，Failed，Succeeded,Unkuown,....  
       
     创建Pod：  
     初始化--|----主容器启动------------------|  
             |poststart---------------pre stop|  
                  存活性探测  
                  就绪性探测  
    Pod生命周期中的重要行为：：  
        初始化容器  
        容器探测：  
            liveness  存活性探测  
            readiness 就绪性探测  
    restartPolicy：  
        Always, OnFailure,Never. Default to Always.  
    探针类型有三种  
        ExecAction、TCPSockketAction、HTTPGetAction

就绪性探测和service ip关系  
      客户端访问直接访问service ip，service ip通过标签选择器选择后端pod执行调度。  
        
      
===================================  
apiVersion: v1  
kind: Pod  
metadata:  
  name: pod-demo  
  namespace: default  
  labels:  
    app: myapp  
    tier: frontend  
spec:  
  containers:  
  - name: myapp  
    image: nginx:1.14-alpine  
    imagePullPolicy: IfNotPresent     
  - name: apache  
    image: httpd:2.4  
    ports:  
    - name: http  
      containerPort:80  
    - name: https  
      containerPort:443  
    command:  
    - "/bin/sh"  
    - "-c"  
    - "sleep 3600"  
  nodeSelector：  
    disktype: ssd   
===============================  
\[root@master manifests\]\# kubectl explain pods.spec.containers  
KIND:     Pod  
VERSION:  v1

RESOURCE: containers <\[\]Object>

DESCRIPTION:  
     List of containers belonging to the pod. Containers cannot currently be  
     added or removed. There must be at least one container in a Pod. Cannot be  
     updated.

A single application container that you want to run within a pod.

FIELDS:  
   args    <\[\]string>  
     Arguments to the entrypoint. The docker image's CMD is used if this is not  
     provided. Variable references $(VAR\_NAME) are expanded using the  
     container's environment. If a variable cannot be resolved, the reference in  
     the input string will be unchanged. The $(VAR\_NAME) syntax can be escaped  
     with a double $$, ie: $$(VAR\_NAME). Escaped references will never be  
     expanded, regardless of whether the variable exists or not. Cannot be  
     updated. More info:  
     https://kubernetes.io/docs/tasks/inject-data-application/define-command-argument-container/\#running-a-command-in-a-shell

command    <\[\]string>  
     Entrypoint array. Not executed within a shell. The docker image's  
     ENTRYPOINT is used if this is not provided. Variable references $(VAR\_NAME)  
     are expanded using the container's environment. If a variable cannot be  
     resolved, the reference in the input string will be unchanged. The  
     $(VAR\_NAME) syntax can be escaped with a double $$, ie: $$(VAR\_NAME).  
     Escaped references will never be expanded, regardless of whether the  
     variable exists or not. Cannot be updated. More info:  
     https://kubernetes.io/docs/tasks/inject-data-application/define-command-argument-container/\#running-a-command-in-a-shell

env    <\[\]Object>  
     List of environment variables to set in the container. Cannot be updated.

envFrom    <\[\]Object>  
     List of sources to populate environment variables in the container. The  
     keys defined within a source must be a C\_IDENTIFIER. All invalid keys will  
     be reported as an event when the container is starting. When a key exists  
     in multiple sources, the value associated with the last source will take  
     precedence. Values defined by an Env with a duplicate key will take  
     precedence. Cannot be updated.

image    <string>  
     Docker image name. More info:  
     https://kubernetes.io/docs/concepts/containers/images This field is  
     optional to allow higher level config management to default or override  
     container images in workload controllers like Deployments and StatefulSets.

imagePullPolicy    <string>  
     Image pull policy. One of Always, Never, IfNotPresent. Defaults to Always  
     if :latest tag is specified, or IfNotPresent otherwise. Cannot be updated.  
     More info:  
     https://kubernetes.io/docs/concepts/containers/images\#updating-images

lifecycle    <Object>  
     Actions that the management system should take in response to container  
     lifecycle events. Cannot be updated.

livenessProbe    <Object>  
     Periodic probe of container liveness. Container will be restarted if the  
     probe fails. Cannot be updated. More info:  
     https://kubernetes.io/docs/concepts/workloads/pods/pod-lifecycle\#container-probes

name    <string> -required-  
     Name of the container specified as a DNS\_LABEL. Each container in a pod  
     must have a unique name (DNS\_LABEL). Cannot be updated.

ports    <\[\]Object>  
     List of ports to expose from the container. Exposing a port here gives the  
     system additional information about the network connections a container  
     uses, but is primarily informational. Not specifying a port here DOES NOT  
     prevent that port from being exposed. Any port which is listening on the  
     default "0.0.0.0" address inside a container will be accessible from the  
     network. Cannot be updated.

readinessProbe    <Object>  
     Periodic probe of container service readiness. Container will be removed  
     from service endpoints if the probe fails. Cannot be updated. More info:  
     https://kubernetes.io/docs/concepts/workloads/pods/pod-lifecycle\#container-probes

resources    <Object>  
     Compute Resources required by this container. Cannot be updated. More info:  
     https://kubernetes.io/docs/concepts/configuration/manage-compute-resources-container/

securityContext    <Object>  
     Security options the pod should run with. More info:  
     https://kubernetes.io/docs/concepts/policy/security-context/ More info:  
     https://kubernetes.io/docs/tasks/configure-pod-container/security-context/

stdin    <boolean>  
     Whether this container should allocate a buffer for stdin in the container  
     runtime. If this is not set, reads from stdin in the container will always  
     result in EOF. Default is false.

stdinOnce    <boolean>  
     Whether the container runtime should close the stdin channel after it has  
     been opened by a single attach. When stdin is true the stdin stream will  
     remain open across multiple attach sessions. If stdinOnce is set to true,  
     stdin is opened on container start, is empty until the first client  
     attaches to stdin, and then remains open and accepts data until the client  
     disconnects, at which time stdin is closed and remains closed until the  
     container is restarted. If this flag is false, a container processes that  
     reads from stdin will never receive an EOF. Default is false

terminationMessagePath    <string>  
     Optional: Path at which the file to which the container's termination  
     message will be written is mounted into the container's filesystem. Message  
     written is intended to be brief final status, such as an assertion failure  
     message. Will be truncated by the node if greater than 4096 bytes. The  
     total message length across all containers will be limited to 12kb.  
     Defaults to /dev/termination-log. Cannot be updated.

terminationMessagePolicy    <string>  
     Indicate how the termination message should be populated. File will use the  
     contents of terminationMessagePath to populate the container status message  
     on both success and failure. FallbackToLogsOnError will use the last chunk  
     of container log output if the termination message file is empty and the  
     container exited with an error. The log output is limited to 2048 bytes or  
     80 lines, whichever is smaller. Defaults to File. Cannot be updated.

tty    <boolean>  
     Whether this container should allocate a TTY for itself, also requires  
     'stdin' to be true. Default is false.

volumeDevices    <\[\]Object>  
     volumeDevices is the list of block devices to be used by the container.  
     This is a beta feature.

volumeMounts    <\[\]Object>  
     Pod volumes to mount into the container's filesystem. Cannot be updated.

workingDir    <string>  
     Container's working directory. If not specified, the container runtime's  
     default will be used, which might be configured in the container image.  
     Cannot be updated.

\[root@master manifests\]\# kubectl explain pods.spec.containers.ports  
KIND:     Pod  
VERSION:  v1

RESOURCE: ports <\[\]Object>

DESCRIPTION:  
     List of ports to expose from the container. Exposing a port here gives the  
     system additional information about the network connections a container  
     uses, but is primarily informational. Not specifying a port here DOES NOT  
     prevent that port from being exposed. Any port which is listening on the  
     default "0.0.0.0" address inside a container will be accessible from the  
     network. Cannot be updated.

ContainerPort represents a network port in a single container.

FIELDS:  
   containerPort    <integer> -required-  
     Number of port to expose on the pod's IP address. This must be a valid port  
     number, 0 < x < 65536.

hostIP    <string>  
     What host IP to bind the external port to.

hostPort    <integer>  
     Number of port to expose on the host. If specified, this must be a valid  
     port number, 0 < x < 65536. If HostNetwork is specified, this must match  
     ContainerPort. Most containers do not need this.

name    <string>  
     If specified, this must be an IANA\_SVC\_NAME and unique within the pod. Each  
     named port in a pod must have a unique name. Name for the port that can be  
     referred to by services.

protocol    <string>  
     Protocol for port. Must be UDP, TCP, or SCTP. Defaults to "TCP".  
       
标签  
\[root@master manifests\]\# kubectl get pods  
NAME                            READY   STATUS    RESTARTS   AGE  
nginx-7849c4bbcd-dscjr          1/1     Running   0          2d20h  
nginx-7849c4bbcd-vdd45          1/1     Running   0          2d20h  
nginx-7849c4bbcd-wrvks          1/1     Running   0          2d20h  
nginx-deploy-84cbfc56b6-mjcw5   1/1     Running   0          2d22h  
pod-demo                        2/2     Running   21         21h  
\[root@master manifests\]\# kubectl get pods --show-labels  
NAME                            READY   STATUS    RESTARTS   AGE     LABELS  
nginx-7849c4bbcd-dscjr          1/1     Running   0          2d20h   pod-template-hash=7849c4bbcd,run=nginx  
nginx-7849c4bbcd-vdd45          1/1     Running   0          2d20h   pod-template-hash=7849c4bbcd,run=nginx  
nginx-7849c4bbcd-wrvks          1/1     Running   0          2d20h   pod-template-hash=7849c4bbcd,run=nginx  
nginx-deploy-84cbfc56b6-mjcw5   1/1     Running   0          2d22h   pod-template-hash=84cbfc56b6,run=nginx-deploy  
pod-demo                        2/2     Running   21         21h     app=myapp,tier=frontend  
\[root@master manifests\]\# kubectl get pods -L app        -L 获取标签为app的标签值  
NAME                            READY   STATUS    RESTARTS   AGE     APP  
nginx-7849c4bbcd-dscjr          1/1     Running   0          2d20h     
nginx-7849c4bbcd-vdd45          1/1     Running   0          2d20h     
nginx-7849c4bbcd-wrvks          1/1     Running   0          2d20h     
nginx-deploy-84cbfc56b6-mjcw5   1/1     Running   0          2d22h     
pod-demo                        2/2     Running   21         21h     myapp  
\[root@master manifests\]\# kubectl get pods -l app   只显标签值为app的pod  
NAME       READY   STATUS    RESTARTS   AGE  
pod-demo   2/2     Running   21         21h  
\[root@master manifests\]\# kubectl get pods -L app,run  
NAME                            READY   STATUS    RESTARTS   AGE     APP     RUN  
nginx-7849c4bbcd-dscjr          1/1     Running   0          2d20h           nginx  
nginx-7849c4bbcd-vdd45          1/1     Running   0          2d20h           nginx  
nginx-7849c4bbcd-wrvks          1/1     Running   0          2d20h           nginx  
nginx-deploy-84cbfc56b6-mjcw5   1/1     Running   0          2d22h           nginx-deploy  
pod-demo                        2/2     Running   21         21h     myapp     
\[root@master manifests\]\# kubectl label pods pod-demo release=canary   打标签  
pod/pod-demo labeled  
\[root@master manifests\]\# kubectl get pods -l app --show-labels  
NAME       READY   STATUS    RESTARTS   AGE   LABELS  
pod-demo   2/2     Running   21         21h   app=myapp,release=canary,tier=frontend  
\[root@master manifests\]\# kubectl label pods pod-demo release=stable  
error: 'release' already has a value (canary), and --overwrite is false  
\[root@master manifests\]\# kubectl label pods pod-demo release=stable --overwrite  覆盖  
pod/pod-demo labeled  
\[root@master manifests\]\# kubectl get pods -l app --show-labels  
NAME       READY   STATUS    RESTARTS   AGE   LABELS  
pod-demo   2/2     Running   21         21h   app=myapp,release=stable,tier=\[root@master manifests\]\# kubectl get pods -l release  
NAME       READY   STATUS    RESTARTS   AGE  
pod-demo   2/2     Running   21         21h  
\[root@master manifests\]\# kubectl get pods -l release,app  
NAME       READY   STATUS    RESTARTS   AGE  
pod-demo   2/2     Running   21         21h

k8s两种标签选择器：  
        等值关系  = ==  
        集合关系    
           KEY in (VALUE1,VALUE2,....)  
           KEY notin (VALUE1,VALUE2,....)  
           KEY   
           !key  
\[root@master manifests\]\# kubectl label pods nginx-deploy-84cbfc56b6-mjcw5 release=canary  
pod/nginx-deploy-84cbfc56b6-mjcw5 labeled  
\[root@master manifests\]\# kubectl get pods -l release,app  
NAME       READY   STATUS    RESTARTS   AGE  
pod-demo   2/2     Running   22         22h  
\[root@master manifests\]\# kubectl get pods -l release=canary  
NAME                            READY   STATUS    RESTARTS   AGE  
nginx-deploy-84cbfc56b6-mjcw5   1/1     Running   0          2d22h  
\[root@master manifests\]\# kubectl get pods -l release=stable,app=myapp  
NAME       READY   STATUS    RESTARTS   AGE  
pod-demo   2/2     Running   22         22h  
\[root@master manifests\]\# kubectl get pods -l release!=canary  
NAME                     READY   STATUS    RESTARTS   AGE  
nginx-7849c4bbcd-dscjr   1/1     Running   0          2d21h  
nginx-7849c4bbcd-vdd45   1/1     Running   0          2d21h  
nginx-7849c4bbcd-wrvks   1/1     Running   0          2d21h  
pod-demo                 2/2     Running   22         22h

\[root@master manifests\]\# kubectl get pods -l "release in (canary,bete,aplha)"  
NAME                            READY   STATUS    RESTARTS   AGE  
nginx-deploy-84cbfc56b6-mjcw5   1/1     Running   0          2d22h  
\[root@master manifests\]\# kubectl get pods -l "release notin (canary,bete,aplha)"  
NAME                     READY   STATUS    RESTARTS   AGE  
nginx-7849c4bbcd-dscjr   1/1     Running   0          2d21h  
nginx-7849c4bbcd-vdd45   1/1     Running   0          2d21h  
nginx-7849c4bbcd-wrvks   1/1     Running   0          2d21h  
pod-demo                 2/2     Running   22         22

\[root@master manifests\]\# kubectl get nodes  
NAME     STATUS   ROLES    AGE    VERSION  
master   Ready    master   4d2h   v1.13.3  
node01   Ready    <none>   4d2h   v1.13.3  
node02   Ready    <none>   4d2h   v1.13.3  
\[root@master manifests\]\# kubectl get nodes --show-labels  
NAME     STATUS   ROLES    AGE    VERSION   LABELS  
master   Ready    master   4d2h   v1.13.3   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/hostname=master,node-role.kubernetes.io/master=  
node01   Ready    <none>   4d2h   v1.13.3   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/hostname=node01  
node02   Ready    <none>   4d2h   v1.13.3   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/hostname=node02  
\[root@master manifests\]\# kubectl label nodes node01 disktype=ssd  
node/node01 labeled  
\[root@master manifests\]\# kubectl get nodes --show-labels  
NAME     STATUS   ROLES    AGE    VERSION   LABELS  
master   Ready    master   4d2h   v1.13.3   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/hostname=master,node-role.kubernetes.io/master=  
node01   Ready    <none>   4d2h   v1.13.3   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,disktype=ssd,kubernetes.io/hostname=node01  
node02   Ready    <none>   4d2h   v1.13.3   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/hostname=node02

指定带ssd标签的主机  
\[root@master manifests\]\# cat pod-demo.yaml   
apiVersion: v1  
kind: Pod  
metadata:  
  name: pod-demo  
  namespace: default  
  labels:  
    app: myapp  
    tier: frontend  
spec:  
  containers:  
  - name: myapp  
    image: nginx:1.14-alpine  
  - name: apache  
    image: httpd:2.4  
    ports:  
    - name: http  
      containerPort: 80  
    - name: https  
      containerPort: 443  
    command:  
    - "/bin/sh"  
    - "-c"  
    - "sleep 3600"  
  nodeSelector:  
    disktype: ssd  
\[root@master manifests\]\# kubectl get pods  
NAME                            READY   STATUS    RESTARTS   AGE  
nginx-7849c4bbcd-dscjr          1/1     Running   0          2d21h  
nginx-7849c4bbcd-vdd45          1/1     Running   0          2d21h  
nginx-7849c4bbcd-wrvks          1/1     Running   0          2d21h  
nginx-deploy-84cbfc56b6-mjcw5   1/1     Running   0          2d22h  
pod-demo                        2/2     Running   0          9s  
\[root@master manifests\]\# kubectl get pods  
NAME                            READY   STATUS    RESTARTS   AGE  
nginx-7849c4bbcd-dscjr          1/1     Running   0          2d21h  
nginx-7849c4bbcd-vdd45          1/1     Running   0          2d21h  
nginx-7849c4bbcd-wrvks          1/1     Running   0          2d21h  
nginx-deploy-84cbfc56b6-mjcw5   1/1     Running   0          2d22h  
pod-demo                        2/2     Running   0          11s  
\[root@master manifests\]\# kubectl get pods -o wide  
NAME                            READY   STATUS    RESTARTS   AGE     IP            NODE     NOMINATED NODE   READINESS GATES  
nginx-7849c4bbcd-dscjr          1/1     Running   0          2d21h   10.244.1.13   node01   <none>           <none>  
nginx-7849c4bbcd-vdd45          1/1     Running   0          2d21h   10.244.2.15   node02   <none>           <none>  
nginx-7849c4bbcd-wrvks          1/1     Running   0          2d21h   10.244.1.14   node01   <none>           <none>  
nginx-deploy-84cbfc56b6-mjcw5   1/1     Running   0          2d22h   10.244.2.9    node02   <none>           <none>  
pod-demo                        2/2     Running   0          16s     10.244.1.17   node01   <none>           <none>  
\[root@master manifests\]\# kubectl describe pod pod-demo

探针测试  
探针类型有三种  
        ExecAction、TCPSockketAction、HTTPGetAction   
          
ExecAction实例  
\[root@master manifests\]\# cat liveness-exec.yaml   
apiVersion: v1  
kind: Pod  
metadata:  
  name: liveness-exec-pod  
  namespace: default  
spec:  
  containers:  
  - name: liveness-exec-container  
    image: busybox:latest  
    command: \["/bin/sh","touch /tmp/healthy; sleep 30; rm -rf /tmp/healthy; sleep 3600"\]  
    livenessProbe:  
      exec:  
        command: \["test","-e","/tmp/healthy"\]  
      initialDelaySeconds: 1  
      periodSeconds: 3  
\[root@master manifests\]\# kubectl get pods -w  
NAME                            READY   STATUS             RESTARTS   AGE  
liveness-exec-pod               0/1     CrashLoopBackOff   3          72s   这里已经重启3次了  
nginx-7849c4bbcd-dscjr          1/1     Running            0          3d21h  
nginx-7849c4bbcd-vdd45          1/1     Running            0          3d21h  
nginx-7849c4bbcd-wrvks          1/1     Running            0          3d21h  
nginx-deploy-84cbfc56b6-mjcw5   1/1     Running            0          3d22h  
^C\[root@master manifests\]\# kubectl describe liveness-exec-pod  
error: the server doesn't have a resource type "liveness-exec-pod"  
\[root@master manifests\]\# kubectl describe pod liveness-exec-pod  
Name:               liveness-exec-pod  
Namespace:          default  
Priority:           0  
PriorityClassName:  <none>  
Node:               node01/10.249.6.101  
Start Time:         Tue, 05 Mar 2019 08:48:00 -0500  
Labels:             <none>  
Annotations:        <none>  
Status:             Running  
IP:                 10.244.1.18  
Containers:  
  liveness-exec-container:  
    Container ID:  docker://abe787745904f4c45324ea80b3d587dc11ed9e382ebdead4e9f31e8041dcc4b7  
    Image:         busybox:latest  
    Image ID:      docker-pullable://busybox@sha256:061ca9704a714ee3e8b80523ec720c64f6209ad3f97c0ff7cb9ec7d19f15149f  
    Port:          <none>  
    Host Port:     <none>  
    Command:  
      /bin/sh  
      touch /tmp/healthy; sleep 30; rm -rf /tmp/healthy; sleep 3600  
    State:          Waiting  
      Reason:       CrashLoopBackOff  
    Last State:     Terminated  
      Reason:       Error  
      Exit Code:    2  
      Started:      Tue, 05 Mar 2019 08:49:42 -0500  
      Finished:     Tue, 05 Mar 2019 08:49:42 -0500  
    Ready:          False  
    Restart Count:  4      这个库  
    Liveness:       exec \[test -e /tmp/healthy\] delay=1s timeout=1s period=3s \#success=1 \#failure=3  这里  
    Environment:    <none>  
    Mounts:  
      /var/run/secrets/kubernetes.io/serviceaccount from default-token-6q28w (ro)  
Conditions:  
  Type              Status  
  Initialized       True   
  Ready             False   
  ContainersReady   False   
  PodScheduled      True   
Volumes:  
  default-token-6q28w:  
    Type:        Secret (a volume populated by a Secret)  
    SecretName:  default-token-6q28w  
    Optional:    false  
QoS Class:       BestEffort  
Node-Selectors:  <none>  
Tolerations:     node.kubernetes.io/not-ready:NoExecute for 300s  
                 node.kubernetes.io/unreachable:NoExecute for 300s  
Events:  
  Type     Reason     Age                 From               Message  
  ----     ------     ----                ----               -------  
  Normal   Scheduled  117s                default-scheduler  Successfully assigned default/liveness-exec-pod to node01  
  Normal   Pulling    69s (x4 over 116s)  kubelet, node01    pulling image "busybox:latest"  
  Normal   Pulled     68s (x4 over 115s)  kubelet, node01    Successfully pulled image "busybox:latest"  
  Normal   Created    68s (x4 over 115s)  kubelet, node01    Created container  
  Normal   Started    67s (x4 over 114s)  kubelet, node01    Started container  
  Warning  BackOff    66s (x9 over 111s)  kubelet, node01    Back-off restarting failed container  
\[root@master manifests\]\# kubectl get pods -w  
NAME                            READY   STATUS             RESTARTS   AGE  
liveness-exec-pod               0/1     CrashLoopBackOff   4          2m46s  重启四次了  
nginx-7849c4bbcd-dscjr          1/1     Running            0          3d21h  
nginx-7849c4bbcd-vdd45          1/1     Running            0          3d21h  
nginx-7849c4bbcd-wrvks          1/1     Running            0          3d21h  
nginx-deploy-84cbfc56b6-mjcw5   1/1     Running            0          3d22h  
\[root@master manifests\]\# kubectl delete -f liveness-exec.yaml    删除掉他  
pod "liveness-exec-pod" deleted

HTTPGetAction 实例       
\[root@master manifests\]\# cat liveness-httpget.yaml   
apiVersion: v1  
kind: Pod  
metadata:  
  name: liveness-httpget-pod  
  namespace: default  
spec:  
  containers:  
  - name: liveness-httpget-container  
    image: nginx  
    ports:  
    - name: http  
      containerPort: 80  
    livenessProbe:  
      httpGet:  
        port: http  
        path: /index.html  
      initialDelaySeconds: 1  
      periodSeconds: 3  
\[root@master manifests\]\# kubectl create -f liveness-httpget.yaml   
pod/liveness-httpget-pod created  
\[root@master manifests\]\# kubectl get pod  
NAME                            READY   STATUS    RESTARTS   AGE  
liveness-httpget-pod            1/1     Running   0          8s  
nginx-7849c4bbcd-dscjr          1/1     Running   0          3d21h  
nginx-7849c4bbcd-vdd45          1/1     Running   0          3d21h  
nginx-7849c4bbcd-wrvks          1/1     Running   0          3d21h  
nginx-deploy-84cbfc56b6-mjcw5   1/1     Running   0          3d22h  
\[root@master manifests\]\# kubectl describe pod liveness-httpget-pod  
Name:               liveness-httpget-pod  
Namespace:          default  
Priority:           0  
PriorityClassName:  <none>  
Node:               node02/10.249.6.102  
Start Time:         Tue, 05 Mar 2019 08:58:45 -0500  
Labels:             <none>  
Annotations:        <none>  
Status:             Running  
IP:                 10.244.2.17  
Containers:  
  liveness-httpget-container:  
    Container ID:   docker://3ca6b2cd842dc03f89c600b18942271a69bb34b541411e4186ee8242c892e821  
    Image:          nginx  
    Image ID:       docker-pullable://nginx@sha256:18c0755594af107923baa2e65fcef35aea4ab0cea7862d19c27aa127bacb458e  
    Port:           80/TCP  
    Host Port:      0/TCP  
    State:          Running  
      Started:      Tue, 05 Mar 2019 08:58:51 -0500  
    Ready:          True  
    Restart Count:  0  
    Liveness:       http-get http://:http/index.html delay=1s timeout=1s period=3s \#success=1 \#failure=3  
    Environment:    <none>  
    Mounts:  
      /var/run/secrets/kubernetes.io/serviceaccount from default-token-6q28w (ro)  
Conditions:  
  Type              Status  
  Initialized       True   
  Ready             True   
  ContainersReady   True   
  PodScheduled      True   
Volumes:  
  default-token-6q28w:  
    Type:        Secret (a volume populated by a Secret)  
    SecretName:  default-token-6q28w  
    Optional:    false  
QoS Class:       BestEffort  
Node-Selectors:  <none>  
Tolerations:     node.kubernetes.io/not-ready:NoExecute for 300s  
                 node.kubernetes.io/unreachable:NoExecute for 300s  
Events:  
  Type    Reason     Age   From               Message  
  ----    ------     ----  ----               -------  
  Normal  Scheduled  88s   default-scheduler  Successfully assigned default/liveness-httpget-pod to node02  
  Normal  Pulling    87s   kubelet, node02    pulling image "nginx"  
  Normal  Pulled     82s   kubelet, node02    Successfully pulled image "nginx"  
  Normal  Created    82s   kubelet, node02    Created container  
  Normal  Started    82s   kubelet, node02    Started container  
手动进入容器  
\[root@master manifests\]\# kubectl exec -it liveness-httpget-pod -- /bin/sh  
\#  
\# ls  
50x.html  index.html  
\# rm index.html  
\# ls   
50x.html  
这里立马退出了容器命令行  
\[root@master manifests\]\# kubectl describe pod liveness-httpget-pod  
Name:               liveness-httpget-pod  
Namespace:          default  
Priority:           0  
PriorityClassName:  <none>  
Node:               node02/10.249.6.102  
Start Time:         Tue, 05 Mar 2019 08:58:45 -0500  
Labels:             <none>  
Annotations:        <none>  
Status:             Running  
IP:                 10.244.2.17  
Containers:  
  liveness-httpget-container:  
    Container ID:   docker://09feb70eeb2fe1870fb63145770321afc54470353bfeebba5151c0acadc915cf  
    Image:          nginx  
    Image ID:       docker-pullable://nginx@sha256:18c0755594af107923baa2e65fcef35aea4ab0cea7862d19c27aa127bacb458e  
    Port:           80/TCP  
    Host Port:      0/TCP  
    State:          Running  
      Started:      Tue, 05 Mar 2019 09:03:02 -0500  
    Last State:     Terminated  
      Reason:       Completed  
      Exit Code:    0  
      Started:      Tue, 05 Mar 2019 08:58:51 -0500  
      Finished:     Tue, 05 Mar 2019 09:03:00 -0500  
    Ready:          True  
    Restart Count:  1  这里重启了一次  
    Liveness:       http-get http://:http/index.html delay=1s timeout=1s period=3s \#success=1 \#failure=3 这里失败了3次  
    Environment:    <none>  
    Mounts:  
      /var/run/secrets/kubernetes.io/serviceaccount from default-token-6q28w (ro)  
Conditions:  
  Type              Status  
  Initialized       True   
  Ready             True   
  ContainersReady   True   
  PodScheduled      True   
Volumes:  
  default-token-6q28w:  
    Type:        Secret (a volume populated by a Secret)  
    SecretName:  default-token-6q28w  
    Optional:    false  
QoS Class:       BestEffort  
Node-Selectors:  <none>  
Tolerations:     node.kubernetes.io/not-ready:NoExecute for 300s  
                 node.kubernetes.io/unreachable:NoExecute for 300s  
Events:  
  Type     Reason     Age                  From               Message  
  ----     ------     ----                 ----               -------  
  Normal   Scheduled  5m2s                 default-scheduler  Successfully assigned default/liveness-httpget-pod to node02  
  Normal   Pulling    47s (x2 over 5m1s)   kubelet, node02    pulling image "nginx"  
  Warning  Unhealthy  47s (x3 over 53s)    kubelet, node02    Liveness probe failed: HTTP probe failed with statuscode: 404  
  Normal   Killing    47s                  kubelet, node02    Killing container with id docker://liveness-httpget-container:Container failed liveness probe.. Container will be killed and recreated.  
  Normal   Pulled     45s (x2 over 4m56s)  kubelet, node02    Successfully pulled image "nginx"  
  Normal   Created    45s (x2 over 4m56s)  kubelet, node02    Created container  
  Normal   Started    45s (x2 over 4m56s)  kubelet, node02    Started container  
\[root@master manifests\]\# kubectl get pod  
NAME                            READY   STATUS    RESTARTS   AGE  
liveness-httpget-pod            1/1     Running   1          6m31s  过一会这里重新部署上了  
nginx-7849c4bbcd-dscjr          1/1     Running   0          3d21h  
nginx-7849c4bbcd-vdd45          1/1     Running   0          3d21h  
nginx-7849c4bbcd-wrvks          1/1     Running   0          3d21h  
nginx-deploy-84cbfc56b6-mjcw5   1/1     Running   0          3d22h

就绪性探测和service ip关系  
   客户端访问直接访问service ip，service ip通过标签选择器选择后端pod执行调度。  
apiVersion: v1  
kind: Pod  
metadata:  
  name: readiness-httpget-pod  
  namespace: default  
spec:  
  containers:  
  - name: readiness-httpget-container  
    image: nginx  
    ports:  
    - name: http  
      containerPort: 80  
    readinessProbe:  
      httpGet:  
        port: http  
        path: /index.html  
      initialDelaySeconds: 1  
      periodSeconds: 3  
\[root@master manifests\]\# kubectl create -f readiness-httpget.yaml   
pod/readiness-httpget-pod created  
\[root@master manifests\]\# kubectl get pods  
NAME                            READY   STATUS    RESTARTS   AGE  
liveness-httpget-pod            1/1     Running   1          17m  
nginx-7849c4bbcd-dscjr          1/1     Running   0          3d21h  
nginx-7849c4bbcd-vdd45          1/1     Running   0          3d21h  
nginx-7849c4bbcd-wrvks          1/1     Running   0          3d21h  
nginx-deploy-84cbfc56b6-mjcw5   1/1     Running   0          3d22h  
readiness-httpget-pod           1/1     Running   0          7s  
同样进去删掉  
\[root@master manifests\]\# kubectl exec -it readiness-httpget-pod -- /bin/sh  
\# cd html  
\# ls  
50x.html  index.html  
\# rm index.html  
\[root@master ~\]\# kubectl get pods  
NAME                            READY   STATUS    RESTARTS   AGE  
liveness-httpget-pod            1/1     Running   1          20m  
nginx-7849c4bbcd-dscjr          1/1     Running   0          3d21h  
nginx-7849c4bbcd-vdd45          1/1     Running   0          3d21h  
nginx-7849c4bbcd-wrvks          1/1     Running   0          3d21h  
nginx-deploy-84cbfc56b6-mjcw5   1/1     Running   0          3d22h  
readiness-httpget-pod           0/1     Running   0          2m55s   不就绪了 ，不健康了

创建一个文件  
\[root@master manifests\]\# kubectl exec -it readiness-httpget-pod -- /bin/sh  
 \# echo 1 >index.html  
\[root@master ~\]\# kubectl get pods  
NAME                            READY   STATUS    RESTARTS   AGE  
liveness-httpget-pod            1/1     Running   1          22m  
nginx-7849c4bbcd-dscjr          1/1     Running   0          3d21h  
nginx-7849c4bbcd-vdd45          1/1     Running   0          3d21h  
nginx-7849c4bbcd-wrvks          1/1     Running   0          3d21h  
nginx-deploy-84cbfc56b6-mjcw5   1/1     Running   0          3d22h  
readiness-httpget-pod           1/1     Running   0          5m2s   恢复了

生命周期存活检测    
apiVersion: v1  
kind: Pod  
metadata:  
  name: poststart-pod  
  namespace: default  
spec:  
  containers:  
  - name: busybox-httpd  
    image: busybox:latest  
    lifecycle:  
      postStart:  
        exec:  
          command: \["/bin/sh","-c","mkdir -p /data/web/html; echo home\_page >> /data/web/html/index.html"\]  
    command: \["/bin/httpd"\]  
    args: \["-f","-h /data/web/html"\]

群名称：k8s学习群   群   号：153144292