kubernetes基础使用

水深无声 2022-04-24 14:34 279阅读 0赞

官方文档：[https://v1-13.docs.kubernetes.io/zh/docs/tutorials/kubernetes-basics/][https_v1-13.docs.kubernetes.io_zh_docs_tutorials_kubernetes-basics]  
pods生命周期:[https://v1-13.docs.kubernetes.io/docs/concepts/workloads/pods/pod-lifecycle/][https_v1-13.docs.kubernetes.io_docs_concepts_workloads_pods_pod-lifecycle]  
配置: [https://v1-13.docs.kubernetes.io/docs/concepts/configuration/][https_v1-13.docs.kubernetes.io_docs_concepts_configuration]  
labels: [https://v1-13.docs.kubernetes.io/docs/concepts/overview/working-with-objects/labels/][https_v1-13.docs.kubernetes.io_docs_concepts_overview_working-with-objects_labels]  
Deployments: [https://v1-13.docs.kubernetes.io/docs/concepts/workloads/controllers/deployment/][https_v1-13.docs.kubernetes.io_docs_concepts_workloads_controllers_deployment]  
Services: [https://v1-13.docs.kubernetes.io/docs/concepts/services-networking/service/][https_v1-13.docs.kubernetes.io_docs_concepts_services-networking_service]  
Scaling: [https://v1-13.docs.kubernetes.io/docs/tutorials/kubernetes-basics/scale/scale-intro/][https_v1-13.docs.kubernetes.io_docs_tutorials_kubernetes-basics_scale_scale-intro]  
autoscale: [https://v1-13.docs.kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale/][https_v1-13.docs.kubernetes.io_docs_tasks_run-application_horizontal-pod-autoscale]

#查看k8s版本
    kubectl version
    
    #查看所有的节点
    kubectl get nodes
    
    #部署应用
    kubectl run  kubernetes-bootcamp --image=jocatalin/kubernetes-bootcamp:v1 --port=8080
    
    #查看部署应用列表 
    kubectl get deployments 
    
    #查看所有pod
    kubectl get pods
    
    #获取执行中的pod并设置成环境变量POD_NAME
    export POD_NAME=$(kubectl get pods -o go-template --template '{
        {range .items}}{
        {.metadata.name}}{
        {"\n"}}{
        {end}}')
    echo Name of the Pod: $POD_NAME

#访问pod
    curl http://localhost:8001/api/v1/namespaces/default/pods/$POD_NAME/proxy/

kubectl 故障排查

kubectl get pods #查看resources列表
    kubectl describe pods  #查看具体的resources情况
    kubectl logs $POD_NAME  #查看pod里的容器日志
    kubectl exec #在pod里的容器里执行命令
    kubectl exec $POD_NAME env #查看pod环境变量
    kubectl exec -ti $POD_NAME bash #进入pod终端

Service & labels  
Service type

<table> 
 <thead> 
  <tr> 
   <th>类型</th> 
   <th>说明</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td align="left">ClusterIP</td> 
   <td>默认选项，只能集群内部访问</td> 
  </tr> 
  <tr> 
   <td align="left">NodePort</td> 
   <td>使用NAT暴露每个节点的相同端口<br>并使用&lt;NodeIP&gt;:&lt;NodePort&gt; 方式让集群外部访问<br>ClusterIP的超集</td> 
  </tr> 
  <tr> 
   <td align="left">LoadBalancer</td> 
   <td>创建负载均衡器分配一个固定的IP<br>NodePort的超集</td> 
  </tr> 
  <tr> 
   <td align="left">ExternalName</td> 
   <td>使用域名解析的CNAME来指定名字或者手动自定名字<br>不使用proxy<br> 需要v1.7及以上版本的kube-dns</td> 
  </tr> 
  <tr> 
   <td colspan="2" align="left">更多的内容参考:<br><a href="https://v1-13.docs.kubernetes.io/docs/tutorials/services/source-ip/" rel="nofollow">https://v1-13.docs.kubernetes.io/docs/tutorials/services/source-ip/</a> <br><a href="https://v1-13.docs.kubernetes.io/docs/concepts/services-networking/connect-applications-service/" rel="nofollow">https://v1-13.docs.kubernetes.io/docs/concepts/services-networking/connect-applications-service/</a> </td> 
  </tr> 
 </tbody> 
</table>

![service][]

labels  
service通过labels把一组pods管理起来。  
比如通过labels指定开发、测试、生产环境  
比如打版本tag  
使用标签分类  
![label][]

#获取service
    kubectl get services 
    
    #指定service type
    kubectl expose deployment/kubernetes-bootcamp --type="NodePort" --port 8080 
    
    #查看指定services信息
    kubectl describe services/kubernetes-bootcamp
    
    #设置NODE_PORT端口为环境变量
    export NODE_PORT=$(kubectl get services/kubernetes-bootcamp -o go-template='{
        {(index .spec.ports 0).nodePort}}')
    echo NODE_PORT=$NODE_PORT
    
    #查看部署情况
    kubectl describe deployment 
    
    #-l根据label查询pods
    kubectl get pods -l run=kubernetes-bootcamp
    
    #-l根据label查询services 
    kubectl get services -l run=kubernetes-bootcamp
    
    export POD_NAME=$(kubectl get pods -o go-template --template '{
        {range .items}}{
        {.metadata.name}}{
        {"\n"}}{
        {end}}')
    echo Name of the Pod: $POD_NAME
    
    #设置label,label是key/value对
    kubectl label pod $POD_NAME app=v1
    
    #根据label查询pods
    kubectl get pods -l app=v1
    
    #删除service
    kubectl delete service -l run=kubernetes-bootcamp
    
    #pod里执行命令
    kubectl exec -ti $POD_NAME curl localhost:808

扩缩容

kubectl get deployments
    
    #扩容成4个
    kubectl scale deployments/kubernetes-bootcamp --replicas=4
    
    #查看pod是否变成4个
    kubectl get pods -o wide
    
    #查看deployments详情
    kubectl describe deployments/kubernetes-bootcamp
    
    #设置环境变量
    export NODE_PORT=$(kubectl get services/kubernetes-bootcamp -o go-template='{
        {(index .spec.ports 0).nodePort}}')
    echo NODE_PORT=$NODE_PORT
    
    #缩容
    kubectl scale deployments/kubernetes-bootcamp --replicas=2

滚动升级

#查看deployments
    kubectl get deployments
    kubectl get pods
    kubectl describe pods
    #滚动升级
    kubectl set image deployments/kubernetes-bootcamp kubernetes-bootcamp=jocatalin/kubernetes-bootcamp:v2
    
    #查看升级是否成功
    kubectl describe services/kubernetes-bootcamp
    
    #查看升级状态
    kubectl rollout status deployments/kubernetes-bootcamp
    
    #升级一个不存在的版本，让升级失败。
    kubectl set image deployments/kubernetes-bootcamp kubernetes-bootcamp=gcr.io/google-samples/kubernetes-bootcamp:v10
    
    #查看pods是否失败
    kubectl  get pods
    
    #查看失败日志
    kubectl logs  $POD_NAME
    
    #回退版本，然后用上面的命令查看是否回退成功
    kubectl rollout undo deployments/kubernetes-bootcamp

根据上面的内容部署官网的例子:[https://kubernetes.io/docs/tutorials/stateless-application/guestbook/][https_kubernetes.io_docs_tutorials_stateless-application_guestbook]  
image 从docker hub 上找，先pull下来

#在有问题的node上执行以下命令 查看问题
    journalctl -f -u kubelet

[https_v1-13.docs.kubernetes.io_zh_docs_tutorials_kubernetes-basics]: https://v1-13.docs.kubernetes.io/zh/docs/tutorials/kubernetes-basics/
[https_v1-13.docs.kubernetes.io_docs_concepts_workloads_pods_pod-lifecycle]: https://v1-13.docs.kubernetes.io/docs/concepts/workloads/pods/pod-lifecycle/
[https_v1-13.docs.kubernetes.io_docs_concepts_configuration]: https://v1-13.docs.kubernetes.io/docs/concepts/configuration/
[https_v1-13.docs.kubernetes.io_docs_concepts_overview_working-with-objects_labels]: https://v1-13.docs.kubernetes.io/docs/concepts/overview/working-with-objects/labels/
[https_v1-13.docs.kubernetes.io_docs_concepts_workloads_controllers_deployment]: https://v1-13.docs.kubernetes.io/docs/concepts/workloads/controllers/deployment/
[https_v1-13.docs.kubernetes.io_docs_concepts_services-networking_service]: https://v1-13.docs.kubernetes.io/docs/concepts/services-networking/service/
[https_v1-13.docs.kubernetes.io_docs_tutorials_kubernetes-basics_scale_scale-intro]: https://v1-13.docs.kubernetes.io/docs/tutorials/kubernetes-basics/scale/scale-intro/
[https_v1-13.docs.kubernetes.io_docs_tasks_run-application_horizontal-pod-autoscale]: https://v1-13.docs.kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale/
[service]: /images/20220214/32269aca8c894cf58f5b0fbd22900c17.png
[label]: /images/20220214/46cdc84ef1a2402caff3b39d049a0684.png
[https_kubernetes.io_docs_tutorials_stateless-application_guestbook]: https://kubernetes.io/docs/tutorials/stateless-application/guestbook/