kubectl作为我们主要的操作K8S的工具，其具备非常丰富的功能，但是如果不经过打磨，使用起来还是存在诸多不便，今天我们来看看如何将我们的kubectl打磨的更加易用。
一、命令自动补全
kubectl中提供非常多的命令，如果每一次都要手动一个字符一个字符的敲未免太累了，那么如何配置自动补全呢？这里以ubuntu系统为例：
1、安装auto-completion工具
$ sudo apt update Hit:1 http://archive.ubuntu.com/ubuntu bionic InRelease Hit:2 http://security.ubuntu.com/ubuntu bionic-security InRelease Hit:3 http://archive.ubuntu.com/ubuntu bionic-updates InRelease Hit:4 https://download.docker.com/linux/ubuntu bionic InRelease Hit:5 http://archive.ubuntu.com/ubuntu bionic-backports InRelease Reading package lists... Done Building dependency tree Reading state information... Done 144 packages can be upgraded. Run 'apt list --upgradable' to see them. $ sudo apt install bash-completion Reading package lists... Done Building dependency tree Reading state information... Done bash-completion is already the newest version (1:2.8-1ubuntu1). 0 upgraded, 0 newly installed, 0 to remove and 144 not upgraded.
PS：如果是centos系统，则使用yum install bash-completion -y命令安装
2、配置自动补全
Bash：
source <(kubectl completion bash) echo "source <(kubectl completion bash)" >> ~/.bashrc
Zsh：
source <(kubectl completion zsh) echo "[[ $commands[kubectl] ]] && source <(kubectl completion zsh)" >> ~/.zshrc
配置后就可以通过Tab键自动补全命令啦！
二、配置kubectl别名
我们可以通过设置别名简化kubectl命令，编辑.bashrc文件，添加如下内容：
alias sudo='sudo ' alias k='kubectl' alias ka='kubectl apply --recursive -f' alias kex='kubectl exec -i -t' alias klo='kubectl logs -f' alias kg='kubectl get' alias kd='kubectl describe'
PS：alias sudo是为了解决sudo下别名不可用问题
保存后记得执行 source ~/.bashrc哈，接着我们体验下：
$ sudo ka webapp_pod.yaml pod/webapp created $ sudo kg pods NAME READY STATUS RESTARTS AGE webapp 0/2 ContainerCreating 0 7s $ sudo kd pod webapp Name: webapp Namespace: default Priority: 0 Node: ayato/172.16.194.135 Start Time: Wed, 09 Feb 2022 14:04:44 +0000 Labels: app=webapp Annotations: <none> Status: Running IP: 172.17.0.6 IPs: IP: 172.17.0.6 Containers: webapp: Container ID: docker://d9ddf9dd47de12b53f2119bf75df6706bee2e7711509638ad52adc9addeda704 Image: 172.16.194.135:5000/webapp:1.0 Image ID: docker-pullable://172.16.194.135:5000/webapp@sha256:df3a447a013ada0642dec67bb31976f42f1a0699a68873d0452f514fa24e5c77 Port: 5000/TCP Host Port: 0/TCP State: Running Started: Wed, 09 Feb 2022 14:04:46 +0000 Ready: True Restart Count: 0 Environment: <none> Mounts: /tmp from webapp-logs (rw) /var/run/secrets/kubernetes.io/serviceaccount from default-token-pcr2h (ro) busybox: Container ID: docker://6a6a35a628a782fc643af3dd49986bbc77c23de1ae4726bc521c77f61abbbf5d Image: busybox Image ID: docker-pullable://busybox@sha256:afcc7f1ac1b49db317a7196c902e61c6c3c4607d63599ee1a82d702d249a0ccb Port: <none> Host Port: <none> Command: sh -c tail -f /logs/log.out State: Running Started: Wed, 09 Feb 2022 14:06:53 +0000 Ready: True Restart Count: 0 Environment: <none> Mounts: /logs from webapp-logs (rw) /var/run/secrets/kubernetes.io/serviceaccount from default-token-pcr2h (ro) Conditions: Type Status Initialized True Ready True ContainersReady True PodScheduled True Volumes: webapp-logs: Type: EmptyDir (a temporary directory that shares a pod's lifetime) Medium: SizeLimit: <unset> default-token-pcr2h: Type: Secret (a volume populated by a Secret) SecretName: default-token-pcr2h Optional: false QoS Class: BestEffort Node-Selectors: <none> Tolerations: node.kubernetes.io/not-ready:NoExecute op=Exists for 300s node.kubernetes.io/unreachable:NoExecute op=Exists for 300s Events: Type Reason Age From Message ---- ------ ---- ---- ------- Normal Scheduled 2m23s default-scheduler Successfully assigned default/webapp to ayato Normal Pulled 2m22s kubelet Container image "172.16.194.135:5000/webapp:1.0" already present on machine Normal Created 2m21s kubelet Created container webapp Normal Started 2m21s kubelet Started container webapp Normal Pulling 2m21s kubelet Pulling image "busybox" Normal Pulled 15s kubelet Successfully pulled image "busybox" in 14.633078305s Normal Created 15s kubelet Created container busybox Normal Started 14s kubelet Started container busybox
真的是飞一般的感觉！！！
三、Context和Namespace切换
我们在公司的容器平台上使用kubectl时，经常需要切换context和namespace，导致命令非常繁琐，那有没有简便的方式呢？—— kubectx
kubectx安装
$ sudo git clone https://github.com/ahmetb/kubectx /opt/kubectx Cloning into '/opt/kubectx'... remote: Enumerating objects: 1457, done. remote: Counting objects: 100% (172/172), done. remote: Compressing objects: 100% (115/115), done. remote: Total 1457 (delta 85), reused 97 (delta 51), pack-reused 1285 Receiving objects: 100% (1457/1457), 905.30 KiB | 69.00 KiB/s, done. Resolving deltas: 100% (817/817), done. $ sudo ln -s /opt/kubectx/kubens /usr/local/bin/kubectl-ns $ sudo ln -s /opt/kubectx/kubectx /usr/local/bin/kubectl-ctx
我们来看一下效果：
$ sudo k ctx minikube $ sudo k ctx minikube Switched to context "minikube". $ sudo k ns default kube-node-lease kube-public kube-system kubernetes-dashboard $ sudo k ns kube-public Context "minikube" modified. Active namespace is "kube-public". $ sudo k ns default Context "minikube" modified. Active namespace is "default".
四、跟踪查看多个Pod的日志
我们一般使用kubectl logs命令查看Pod日志，但是它不能通过-f参数同时跟踪查看多个Pod日志，这就不方便了，毕竟实际生产环境中每个服务都会有多个Pod，这时我们可以使用stern这个工具，它具备如下能力：
- 允许使用正则表达式来选择需要查看的PodName
- 为不同 Pod 的日志展示不同的颜色
- 跟踪日志过程中假如有符合规则的新 Pod 被创建, 那么会自动添加到输出中
首先安装stern（下载stern时可能较慢可以多试几次）：
wget https://github.com/wercker/stern/releases/download/1.11.0/stern_linux_amd64 sudo mv stern_linux_amd64 /usr/local/bin/kubectl-tail sudo chomd +x /usr/local/bin/kubectl-tail
安装完毕后让我一起感受一下stern的魅力吧，我的Pod里面有两个容器：webapp和busybox，如果使用kubectl logs 还得指定具体的容器，而使用stern就没有这样的限制。
$ sudo k tail . + webapp › busybox + webapp › webapp webapp busybox 14:04:53.197 [INFO ] [main] [org.apache.coyote.http11.Http11NioProtocol] Initializing ProtocolHandler ["http-nio-4567"] webapp busybox 14:04:53.200 [INFO ] [main] [org.apache.catalina.core.StandardService] Starting service [Tomcat] webapp busybox 14:04:53.201 [INFO ] [main] [org.apache.catalina.core.StandardEngine] Starting Servlet engine: [Apache Tomcat/9.0.41] webapp busybox 14:04:53.324 [INFO ] [main] [org.apache.catalina.core.ContainerBase.[Tomcat].[localhost].[/]] Initializing Spring embedded WebApplicationContext webapp busybox 14:04:53.325 [INFO ] [main] [org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext] Root WebApplicationContext: initialization completed in 2952 ms webapp busybox 14:04:53.801 [INFO ] [main] [org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor] Initializing ExecutorService 'applicationTaskExecutor' webapp busybox 14:04:54.264 [WARN ] [main] [org.springframework.boot.autoconfigure.thymeleaf.ThymeleafAutoConfiguration$DefaultTemplateResolverConfiguration] Cannot find template location: classpath:/templates/ (please add some templates or check your Thymeleaf configuration) webapp busybox 14:04:54.377 [INFO ] [main] [org.apache.coyote.http11.Http11NioProtocol] Starting ProtocolHandler ["http-nio-4567"] webapp busybox 14:04:54.481 [INFO ] [main] [org.springframework.boot.web.embedded.tomcat.TomcatWebServer] Tomcat started on port(s): 4567 (http) with context path '' webapp busybox 14:04:54.509 [INFO ] [main] [org.demo.webapp.todolist.TodoListApplication] Started TodoListApplication in 6.235 seconds (JVM running for 8.074) webapp webapp webapp webapp . ____ _ __ _ _ webapp webapp /\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \ webapp webapp ( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \ webapp webapp \\/ ___)| |_)| | | | | || (_| | ) ) ) ) webapp webapp ' |____| .__|_| |_|_| |_\__, | / / / / webapp webapp =========|_|==============|___/=/_/_/_/ webapp webapp :: Spring Boot :: (v2.4.2) webapp webapp webapp webapp 14:04:50.124 [INFO ] [main] [org.demo.webapp.todolist.TodoListApplication] Starting TodoListApplication v1.0-SNAPSHOT using Java 1.8.0_111 on webapp with PID 1 (/opt/soft/webapp.jar started by root in /opt/soft) webapp webapp 14:04:50.165 [INFO ] [main] [org.demo.webapp.todolist.TodoListApplication] No active profile set, falling back to default profiles: default webapp webapp 14:04:53.158 [INFO ] [main] [org.springframework.boot.web.embedded.tomcat.TomcatWebServer] Tomcat initialized with port(s): 4567 (http) webapp webapp 14:04:53.197 [INFO ] [main] [org.apache.coyote.http11.Http11NioProtocol] Initializing ProtocolHandler ["http-nio-4567"] webapp webapp 14:04:53.200 [INFO ] [main] [org.apache.catalina.core.StandardService] Starting service [Tomcat] webapp webapp 14:04:53.201 [INFO ] [main] [org.apache.catalina.core.StandardEngine] Starting Servlet engine: [Apache Tomcat/9.0.41] webapp webapp 14:04:53.324 [INFO ] [main] [org.apache.catalina.core.ContainerBase.[Tomcat].[localhost].[/]] Initializing Spring embedded WebApplicationContext webapp webapp 14:04:53.325 [INFO ] [main] [org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext] Root WebApplicationContext: initialization completed in 2952 ms webapp webapp 14:04:53.801 [INFO ] [main] [org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor] Initializing ExecutorService 'applicationTaskExecutor' webapp webapp 14:04:54.264 [WARN ] [main] [org.springframework.boot.autoconfigure.thymeleaf.ThymeleafAutoConfiguration$DefaultTemplateResolverConfiguration] Cannot find template location: classpath:/templates/ (please add some templates or check your Thymeleaf configuration) webapp webapp 14:04:54.377 [INFO ] [main] [org.apache.coyote.http11.Http11NioProtocol] Starting ProtocolHandler ["http-nio-4567"] webapp webapp 14:04:54.481 [INFO ] [main] [org.springframework.boot.web.embedded.tomcat.TomcatWebServer] Tomcat started on port(s): 4567 (http) with context path '' webapp webapp 14:04:54.509 [INFO ] [main] [org.demo.webapp.todolist.TodoListApplication] Started TodoListApplication in 6.235 seconds (JVM running for 8.074)
分类: 容器技术
