常用的KubeCtl命令

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个人习惯

在~/.bash_profile里增加alias: 

alias k='kubectl'

资源相关命令

Pod

创建pod

  • 快速创建pod

    k run mytest --image=k8s.gcr.io/pause:2.0

  • 根据yaml创建pod

    k apply -f my-pause.yaml

列出pod(包含所在的node)

k get pod -n kube-system -o wide

查看pod详情(包含所在的node)

k describe pod nginx

包含如下重要信息:

  • Pod对应的clusterIp
  • Pod所在的nodeName
  • Pod所属的replicaSet Controlled By xxx
  • Pod的事件 Events
  • Pod里container的定义, Volumes的定义, Labels & Annotations

登录pod

k exec -ti <your-pod-name> -n <your-namespace>  -- /bin/sh

查看pod事件

[root@iZ2ze8h8q419hf1fze66dkZ ~]# k get events --sort-by=.metadata.creationTimestamp
LAST SEEN   TYPE      REASON    OBJECT              MESSAGE
3m17s       Normal    BackOff   pod/no-annotation   Back-off pulling image "k8s.gcr.io/pause:2.0"
23m         Warning   Failed    pod/no-annotation   Error: ImagePullBackOff
28m         Warning   Failed    pod/no-annotation   Error: ErrImagePull

查看pod日志

k logs <your-pod-name> -n <your-namespace>

删除pod

k delete pod <your-pod-name> -n <your-namespace>
k delete -f <your-pod.yaml> -n <your-namespace>

注意, k8s里没有停止Pod的概念, 只有删除(delete)

Kubernetes does not allow you to stop or pause a pod’s present state and resume it later. No. It is not feasible to pause a pod and restart it at a later time.

这里可以思考下, pod与vm的区别, 为啥vm可以stop, delete的概念?

Node

获取nodes列表

k get no/node/nodes -o wide

注意, node没有namespace的概念

查看node详情

k describe node <your-node-name>

包含如下重要信息

  • Non-terminated Pods: 即所有在当前Node上的pod
  • Capacity: cpu, mem等, 代表Node整体的.
  • Allocatable: cpu, mem等, 代表Node去除给kubeproxy/kubelet等系统关键组件预留的资源之后, 可以分配给pod的
  • Allocated resources: 已经分配出去的cpu, mem等. 按照所有pod的request进行叠加的.

Service

获取service列表

[root@iZ2ze8h8q419hf1fze66dkZ ~]# k get svc -o wide
NAME            TYPE        CLUSTER-IP        EXTERNAL-IP   PORT(S)   AGE    SELECTOR
kubernetes      ClusterIP   192.168.0.1       <none>        443/TCP   258d   <none>
nginx-service   ClusterIP   192.168.198.117   <none>        80/TCP    5d8h   app.kubernetes.io/name=proxy

注意: 这里的kubernetes就是apiserver的clusterIp地址了

查看svc详情

[root@iZ2ze8h8q419hf1fze66dkZ ~]# k describe svc nginx-service
Name:              nginx-service
Namespace:         default
Labels:            <none>
Annotations:       <none>
Selector:          app.kubernetes.io/name=proxy
Type:              ClusterIP
IP Families:       <none>
IP:                192.168.198.117
IPs:               192.168.198.117
Port:              name-of-service-port  80/TCP
TargetPort:        http-web-svc/TCP
Endpoints:         172.24.241.16:80,172.24.241.17:80,172.24.241.18:80 + 1 more...
Session Affinity:  None
Events:            <none>

查看对应的endpoints

[root@iZ2ze8h8q419hf1fze66dkZ ~]# k get ep
NAME            ENDPOINTS                                                        AGE
kubernetes      10.10.0.162:6443,10.11.0.33:6443,10.9.0.58:6443                  258d
nginx-service   172.24.241.16:80,172.24.241.17:80,172.24.241.18:80 + 1 more...   5d8h

注意: 这里的kubernetes就是apiserver的pod地址了

查看endpoints详情

[root@iZ2ze8h8q419hf1fze66dkZ ~]# k describe ep nginx-service
Name:         nginx-service
Namespace:    default
Labels:       <none>
Annotations:  endpoints.kubernetes.io/last-change-trigger-time: 2022-04-01T15:22:45+08:00
Subsets:
  Addresses:          172.24.241.16,172.24.241.17,172.24.241.18,172.24.241.19
  NotReadyAddresses:  <none>
  Ports:
    Name                  Port  Protocol
    ----                  ----  --------
    name-of-service-port  80    TCP

Events:  <none>

其他

快速创建deploy

k run redis --image=reids

获取deployments列表

k get deploy/deployment/deployments -n <your-namesapce> -o wide

查看deployments详细信息

k describe deploy/deployment <your-deploy-name> -n <your-namesapce>

包含如下关键信息

  • Replicas: 副本个数情况
  • Pod Template: Pod模板的详细信息, 例如label, image等
  • NewReplicaSet: 对应的rs name信息

查看rs列表与详细信息

k get rs
k describe rs

查看cluster详细信息

k cluster-info
k cluster-info dump

快捷修改deploy/pod等配置

如下, 修改完成自动生效:

k edit deploy nginx