博客
关于我
强烈建议你试试无所不能的chatGPT，快点击我
Kubernetes 学习7 Pod控制器应用进阶2
阅读量：7224 次
发布时间：2019-06-29

本文共 14842 字，大约阅读时间需要 49 分钟。

一、容器探测器

　　1、所谓的容器探测无非就是我们在里面设置了一些探针，或者称之为传感器来获取相应的数据作为判定其存活与否或就绪与否的标准，目前k8s所支持的存活性和就绪性探测方式都是一样的。

　　2、k8s的探针类型有三种

　　　　1、ExecAction

　　　　2、TCPSocketAction：TCPSocket探针

　　　　3、HTTPGetAction ： 如果对方是http服务那么直接向对方发http的get请求就可以了

　　3、相应字段在  pods.spec.containers 之上

　　　　a、livenessProbe <Object>

[root@k8smaster ~]# kubectl explain  pods.spec.containers.livenessProbeKIND:     PodVERSION:  v1RESOURCE: livenessProbe DESCRIPTION:     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     Probe describes a health check to be performed against a container to     determine whether it is alive or ready to receive traffic.FIELDS:   exec     #探针     One and only one of the following should be specified. Exec specifies the     action to take.   failureThreshold    
       
         #探测几次都失败才定义失败，默认为3，最小值为1     Minimum consecutive failures for the probe to be considered failed after     having succeeded. Defaults to 3. Minimum value is 1.   httpGet    
             HTTPGet specifies the http request to perform.   initialDelaySeconds    
         
           #不可能主程序启动以后立即对其做探测，因为有可能还没有初始化完成，因此我们要稍微等一点时间再探测，因此其意思为初始化后的延迟探测时间，不定义默认为容器一启动就开始探测。     Number of seconds after the container has started before liveness probes     are initiated. More info:     https://kubernetes.io/docs/concepts/workloads/pods/pod-lifecycle#container-probes   periodSeconds    
          
            #默认每10秒钟探测一次 How often (in seconds) to perform the probe. Default to 10 seconds. Minimum value is 1. successThreshold 
           
             Minimum consecutive successes for the probe to be considered successful after having failed. Defaults to 1. Must be 1 for liveness. Minimum value is 1. tcpSocket 
             TCPSocket specifies an action involving a TCP port. TCP hooks not yet supported timeoutSeconds 
             
               #探测超时时长，默认为1秒 Number of seconds after which the probe times out. Defaults to 1 second. Minimum value is 1. More info: https://kubernetes.io/docs/concepts/workloads/pods/pod-lifecycle#container-probes

　　　　b、readinessProbe <Object>

　　　　c、lifecycle <Object> #生命周期，定义启动后和终止前钩子的

　　4、exec指针探测

[root@k8smaster ~]# kubectl explain  pods.spec.containers.livenessProbe.execKIND:     PodVERSION:  v1RESOURCE: exec DESCRIPTION:     One and only one of the following should be specified. Exec specifies the     action to take.     ExecAction describes a "run in container" action.FIELDS:   command    <[]string>  #运行命令以后来探测其是否执行成功了，如果这个命令的返回值是成功表示存活，若返回值状态码是不成功表示不存活。     Command is the command line to execute inside the container, the working     directory for the command is root ('/') in the container's filesystem. The     command is simply exec'd, it is not run inside a shell, so traditional     shell instructions ('|', etc) won't work. To use a shell, you need to     explicitly call out to that shell. Exit status of 0 is treated as     live/healthy and non-zero is unhealthy.
[root@k8smaster manifests]# lsliveness-exec.yaml  pod-demo.yaml[root@k8smaster manifests]# cat liveness-exec.yaml apiVersion: v1kind: Podmetadata:   name: liveness-exec-pod  namespace: defaultspec:  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"] livenessProbe: exec: command: ["test","-e","/tmp/healthy"] #判断此文件是否存在 initialDelaySeconds: 1 #容器启动后等待1秒开始探测 periodSeconds: 3 #每隔3秒探测一次 restartPolicy: Always [root@k8smaster manifests]# kubectl get pods NAME READY STATUS RESTARTS AGE liveness-exec-pod 1/1 Running 6 9m myapp-848b5b879b-5k4s4 1/1 Running 0 4d myapp-848b5b879b-bzblz 1/1 Running 0 4d myapp-848b5b879b-hzbf5 1/1 Running 0 4d nginx-deploy-5b595999-d9lv5 1/1 Running 0 4d pod-demo 2/2 Running 3 5h [root@k8smaster manifests]# kubectl describe pod liveness-exec-pod Name: liveness-exec-pod Namespace: default Priority: 0 PriorityClassName: 
     
       Node: k8snode2/192.168.10.12 Start Time: Thu, 09 May 2019 19:59:15 +0800 Labels: 
      
        Annotations: 
       
         Status: Running IP: 10.244.2.17 Containers: liveness-exec-container: Container ID: docker://37b9faa3b66df5f74ce43943e20d414a6e0498b261b65e11e7c89ab26c633109  Image: busybox:latest Image ID: docker-pullable://busybox@sha256:4b6ad3a68d34da29bf7c8ccb5d355ba8b4babcad1f99798204e7abb43e54ee3d Port: 
        
          Host Port: 
         
           Command: /bin/sh -c touch /tmp/healthy; sleep 30; rm -f /tmp/healthy; sleep 3600 State: Running Started: Thu, 09 May 2019 20:07:42 +0800 Last State: Terminated Reason: Error Exit Code: 137 Started: Thu, 09 May 2019 20:05:00 +0800 Finished: Thu, 09 May 2019 20:06:09 +0800 Ready: True Restart Count: 6 Liveness: exec [test -e /tmp/healthy] delay=1s timeout=1s period=3s #success=1 #failure=3 Environment: 
          
            Mounts: /var/run/secrets/kubernetes.io/serviceaccount from default-token-jvtl7 (ro) Conditions: Type Status Initialized True Ready True ContainersReady True PodScheduled True Volumes: default-token-jvtl7: Type: Secret (a volume populated by a Secret) SecretName: default-token-jvtl7 Optional: false QoS Class: BestEffort Node-Selectors: 
           
             Tolerations: node.kubernetes.io/not-ready:NoExecute for 300s node.kubernetes.io/unreachable:NoExecute for 300s Events: Type Reason Age From Message ---- ------ ---- ---- ------- Normal Pulled 4d (x4 over 4d) kubelet, k8snode2 Container image "busybox:latest" already present on machine Normal Created 4d (x4 over 4d) kubelet, k8snode2 Created container Normal Started 4d (x4 over 4d) kubelet, k8snode2 Started container Normal Killing 4d (x3 over 4d) kubelet, k8snode2 Killing container with id docker://liveness-exec-container:Container failed liveness probe.. Container will be killed and recreate d. Warning Unhealthy 4d (x13 over 4d) kubelet, k8snode2 Liveness probe failed: Normal Scheduled 9m default-scheduler Successfully assigned default/liveness-exec-pod to k8snode2

　　5、基于tcpSocket探测

[root@k8smaster manifests]#  kubectl explain  pods.spec.containers.livenessProbe.tcpSocketKIND:     PodVERSION:  v1RESOURCE: tcpSocket DESCRIPTION:     TCPSocket specifies an action involving a TCP port. TCP hooks not yet     supported     TCPSocketAction describes an action based on opening a socketFIELDS:   host    
      
        #基于主机，默认为pod自己的IP地址     Optional: Host name to connect to, defaults to the pod IP.   port    
       
         -required- #基于端口     Number or name of the port to access on the container. Number must be in     the range 1 to 65535. Name must be an IANA_SVC_NAME.

　　6、httpGet探测

[root@k8smaster manifests]#  kubectl explain  pods.spec.containers.livenessProbe.httpGetKIND:     PodVERSION:  v1RESOURCE: httpGet DESCRIPTION:     HTTPGet specifies the http request to perform.     HTTPGetAction describes an action based on HTTP Get requests.FIELDS:   host    
      
            Host name to connect to, defaults to the pod IP. You probably want to set     "Host" in httpHeaders instead.   httpHeaders    <[]Object>     Custom headers to set in the request. HTTP allows repeated headers.   path    
       
         #指定地址指定端口的url发送请求，如果响应码为200则ok     Path to access on the HTTP server.   port    
        
          -required- #可以直接引用service的名称而不用端口号     Name or number of the port to access on the container. Number must be in     the range 1 to 65535. Name must be an IANA_SVC_NAME.   scheme    
         
               Scheme to use for connecting to the host. Defaults to HTTP.

　　　　案例如下

[root@k8smaster manifests]# cat liveness-httpget.yaml apiVersion: v1kind: Podmetadata:   name: liveness-httpget-pod  namespace: defaultspec:  containers:  - name: liveness-httpget-container    image: ikubernetes/myapp:v1    imagePullPolicy: IfNotPresent    ports:    - name: http      containerPort: 80    livenessProbe:      httpGet:        port: http #也可以使用80        path: /index.html      initialDelaySeconds: 1 #容器启动后等待1秒开始探测      periodSeconds: 3 #每隔3秒探测一次  restartPolicy: Always

　　7、就绪性探测，其与service调度有着重要的关联性。如果不做就绪性探测那么pod刚创建就立即被关联到service后端对象中，此时pod如果未就绪将造成服务无法被访问，因此几乎只要使用pod就必须做readinessProbe（就绪性检测）。

　　　　其检测方式和探针与liveness一样，只是目标不一样，livenessProbe只是为了判断存活与否，而readinessProbe则是用来判断它就绪与否。因此只是探测命令可能会不一样。

[root@k8smaster manifests]# cat readiness-httpget.yaml apiVersion: v1kind: Podmetadata:   name: readiness-httpget-pod  namespace: defaultspec:  containers:  - name: readiness-httpget-container    image: ikubernetes/myapp:v1    imagePullPolicy: IfNotPresent    ports:    - name: http      containerPort: 80    readinessProbe:      httpGet:        port: http #也可以使用80        path: /index.html      initialDelaySeconds: 1 #容器启动后等待1秒开始探测      periodSeconds: 3 #每隔3秒探测一次  restartPolicy: Always[root@k8smaster manifests]# kubectl create -f readiness-httpget.yaml pod/readiness-httpget-pod created[root@k8smaster manifests]# kubectl get podsNAME                          READY     STATUS    RESTARTS   AGEliveness-httpget-pod          1/1       Running   1          32mmyapp-848b5b879b-5k4s4        1/1       Running   0          4dmyapp-848b5b879b-bzblz        1/1       Running   0          4dmyapp-848b5b879b-hzbf5        1/1       Running   0          4dnginx-deploy-5b595999-d9lv5   1/1       Running   0          5dpod-demo                      2/2       Running   4          6hreadiness-httpget-pod         1/1       Running   0          6s[root@k8smaster manifests]# kubectl describe pod readiness-httpget-podName:               readiness-httpget-podNamespace:          defaultPriority:           0PriorityClassName:  
     
      Node:               k8snode2/192.168.10.12Start Time:         Thu, 09 May 2019 21:02:50 +0800Labels:             
      
       Annotations:        
       
        Status:             RunningIP:                 10.244.2.19Containers:  readiness-httpget-container:    Container ID:   docker://2972a892e1c91c2cfa6168f5729cbf1dae02e079f5bd1e8dc370e2ed56dcbf61    Image:          ikubernetes/myapp:v1    Image ID:       docker-pullable://ikubernetes/myapp@sha256:9c3dc30b5219788b2b8a4b065f548b922a34479577befb54b03330999d30d513    Port:           80/TCP    Host Port:      0/TCP    State:          Running      Started:      Thu, 09 May 2019 21:02:51 +0800    Ready:          True    Restart Count:  0    Readiness:      http-get http://:http/index.html delay=1s timeout=1s period=3s #success=1 #failure=3    Environment:    
        
             Mounts:      /var/run/secrets/kubernetes.io/serviceaccount from default-token-jvtl7 (ro)Conditions:  Type              Status  Initialized       True   Ready             True   ContainersReady   True   PodScheduled      True Volumes:  default-token-jvtl7:    Type:        Secret (a volume populated by a Secret)    SecretName:  default-token-jvtl7    Optional:    falseQoS Class:       BestEffortNode-Selectors:  
         
          Tolerations:     node.kubernetes.io/not-ready:NoExecute for 300s                 node.kubernetes.io/unreachable:NoExecute for 300sEvents:  Type    Reason     Age   From               Message  ----    ------     ----  ----               -------  Normal  Pulled     4d    kubelet, k8snode2  Container image "ikubernetes/myapp:v1" already present on machine  Normal  Created    4d    kubelet, k8snode2  Created container  Normal  Started    4d    kubelet, k8snode2  Started container  Normal  Scheduled  23s   default-scheduler  Successfully assigned default/readiness-httpget-pod to k8snode2#进入容器删除index.html发现不再ready[root@k8smaster manifests]# kubectl get podsNAME                          READY     STATUS    RESTARTS   AGEliveness-httpget-pod          1/1       Running   1          34mmyapp-848b5b879b-5k4s4        1/1       Running   0          4dmyapp-848b5b879b-bzblz        1/1       Running   0          4dmyapp-848b5b879b-hzbf5        1/1       Running   0          4dnginx-deploy-5b595999-d9lv5   1/1       Running   0          5dpod-demo                      2/2       Running   4          6hreadiness-httpget-pod         0/1       Running   0          2m

 　　8、lifecycle <Object> #生命周期，定义启动后和终止前钩子的

[root@k8smaster manifests]# kubectl explain  pods.spec.containers.lifecycleKIND:     PodVERSION:  v1RESOURCE: lifecycle DESCRIPTION:     Actions that the management system should take in response to container     lifecycle events. Cannot be updated.     Lifecycle describes actions that the management system should take in     response to container lifecycle events. For the PostStart and PreStop     lifecycle handlers, management of the container blocks until the action is     complete, unless the container process fails, in which case the handler is     aborted.FIELDS:   postStart     #容器启动后立即执行的操作     PostStart is called immediately after a container is created. If the     handler fails, the container is terminated and restarted according to its     restart policy. Other management of the container blocks until the hook     completes. More info:     https://kubernetes.io/docs/concepts/containers/container-lifecycle-hooks/#container-hooks   preStop     #容器终止前执行的操作     PreStop is called immediately before a container is terminated. The     container is terminated after the handler completes. The reason for     termination is passed to the handler. Regardless of the outcome of the     handler, the container is eventually terminated. Other management of the     container blocks until the hook completes. More info:     https://kubernetes.io/docs/concepts/containers/container-lifecycle-hooks/#container-hooks

　　　　a、postStart ，默认会在容器的command命令运行完后再运行其定义的命令。

[root@k8smaster manifests]# more poststart-pod.yaml apiVersion: v1kind: Podmetadata:    name: poststart-pod    namespace: defaultspec:    containers:    - name: busybox-pod      image: busybox:latest      imagePullPolicy: IfNotPresent      lifecycle:        postStart:          exec:            command: ["mkdir","-p","/data/web/html"]      command: ["/bin/sh","-c"] #默认此命令+args执行完才会执行上面的postStart.exec.command中的命令      args: ["sleep 3600"][root@k8smaster manifests]# kubectl exec -it  poststart-pod /bin/sh/ # ls /data/web/html// # exit[root@k8smaster manifests]# kubectl get podsNAME                          READY     STATUS    RESTARTS   AGEliveness-httpget-pod          1/1       Running   1          1hmyapp-848b5b879b-5k4s4        1/1       Running   0          4dmyapp-848b5b879b-bzblz        1/1       Running   0          4dmyapp-848b5b879b-hzbf5        1/1       Running   0          4dnginx-deploy-5b595999-d9lv5   1/1       Running   0          5dpod-demo                      2/2       Running   5          7hpoststart-pod                 1/1       Running   0          1mreadiness-httpget-pod         1/1       Running   0          58m

　　　　b、preStop ，和postStart类似

　

转载于:https://www.cnblogs.com/Presley-lpc/p/10862836.html

你可能感兴趣的文章
奥迪与Alta达成合作，将为电动汽车打造太阳能天窗
查看>>
【连载】物联网全栈教程-从云端到设备（十一）---调用阿里云API，获取物的属性。...
查看>>
美军制造3D打印无人机，最高时速55英里
查看>>
Netweaver和CloudFoundry里的trace开关
查看>>
工作负载不要全部放在公共云的篮子中！
查看>>
tf.Graph().get_operations
查看>>
【工业串口和网络软件通讯平台(SuperIO)教程】一.通讯机制
查看>>
[图文教程]阿里云万网域名一键签发SSL证书 快捷申请免费SSL证书
查看>>
区块链简介
查看>>
大谷无人机将追求“才貌双全”
查看>>
量子世界的十个事实
查看>>
U-Boot启动过程完全分析
查看>>
Web性能优化工具WebPageTest（二）——性能数据
查看>>
Lucene 6.0中BooleanQuery
查看>>
数据库反规范设计
查看>>
Oracle数据库在线备份原理
查看>>
阿里云MaxCompute香港开服 将引入更多人工智能服务
查看>>
你的指纹还安全吗？ - BlackHat 2015 黑帽大会总结 day 2
查看>>
2、SRX笔记及基础配置
查看>>
RH134 UNIT7
查看>>
喝酒易醉，品茶养心，人生如梦，品茶悟道，何以解忧？唯有杜康！-- 愿君每日到此一游！
当前时间: 2025-02-12 13:23:23   当前IP: 3.22.79.212   联系邮箱:javaeecc@qq.com     Copyright © 2020 - 2022 baihongyu.com 京ICP备2021015314号-2
强烈建议你试试无所不能的CHAT-GPT，快点击我
强烈建议你试试无所不能的CHAT-GPT，快点击我