kubectl插件管理器krew

1 krew

krew是kubectl命令行的插件管理器，可以和yum一样，查找，安装，更新插件，让插件使用起来更方便。

2 安装

从github下载最新的安装包，然后解压安装，

(
  set -x; cd "$(mktemp -d)" &&
  OS="$(uname | tr '[:upper:]' '[:lower:]')" &&
  ARCH="$(uname -m | sed -e 's/x86_64/amd64/' -e 's/\(arm\)\(64\)\?.*/\1\2/' -e 's/aarch64$/arm64/')" &&
  KREW="krew-${OS}_${ARCH}" &&
  curl -fsSLO "https://github.com/kubernetes-sigs/krew/releases/latest/download/${KREW}.tar.gz" &&
  tar zxvf "${KREW}.tar.gz" &&
  ./"${KREW}" install krew
)

然后需要将krew路径添加到PATH环境变量中，可以放到对应用户home目录下.bash_profile

echo 'export PATH="${KREW_ROOT:-$HOME/.krew}/bin:$PATH"' >> ~/.bash_profile

3 使用

• 查找插件

[root@master ~]# kubectl krew search
NAME                            DESCRIPTION                                         INSTALLED
access-matrix                   Show an RBAC access matrix for server resources     no
accurate                        Manage Accurate, a multi-tenancy controller         no
advise-policy                   Suggests PodSecurityPolicies and OPA Policies f...  no
advise-psp                      Suggests PodSecurityPolicies for cluster.           no
...

• 安装插件

[root@master ~]# kubectl krew install get-all
Updated the local copy of plugin index.
Updated the local copy of plugin index "kvaps".
Installing plugin: get-all
Installed plugin: get-all
\
 | Use this plugin:
 | 	kubectl get-all
 | Documentation:
 | 	https://github.com/corneliusweig/ketall
/
WARNING: You installed plugin "get-all" from the krew-index plugin repository.
   These plugins are not audited for security by the Krew maintainers.
   Run them at your own risk.

• 更新插件

[root@master ~]# kubectl krew upgrade
Updated the local copy of plugin index.
Updated the local copy of plugin index "kvaps".
Upgrading plugin: get-all
Skipping plugin get-all, it is already on the newest version
Upgrading plugin: krew
Skipping plugin krew, it is already on the newest version

• 使用插件

[root@master ~]# kubectl get-all -n kyverno
NAME                                             NAMESPACE  AGE
configmap/istio-ca-root-cert                     kyverno    55d  
configmap/kube-root-ca.crt                       kyverno    55d  
secret/default-token-b5k8b                       kyverno    55d  
secret/kyverno-svc.kyverno.svc.kyverno-tls-ca    kyverno    55d  
secret/kyverno-svc.kyverno.svc.kyverno-tls-pair  kyverno    55d  
serviceaccount/default                           kyverno    55d  
lease.coordination.k8s.io/kyverno                kyverno    55d  
lease.coordination.k8s.io/kyvernopre             kyverno    55d  
lease.coordination.k8s.io/kyvernopre-lock        kyverno    55d  
lease.coordination.k8s.io/webhook-register       kyverno    55d  

• 卸载插件

[root@master ~]# kubectl krew uninstall get-all
Uninstalled plugin: get-all

4 常用插件

• get-all 可以列出某个namespace下所有资源，是真的所有资源，和kubectl get all不同

[root@master ~]# kubectl get all -n kyverno
No resources found in kyverno namespace.
[root@master ~]# kubectl get-all -n kyverno
NAME                                             NAMESPACE  AGE
configmap/istio-ca-root-cert                     kyverno    55d  
configmap/kube-root-ca.crt                       kyverno    55d  
secret/default-token-b5k8b                       kyverno    55d  
secret/kyverno-svc.kyverno.svc.kyverno-tls-ca    kyverno    55d  
secret/kyverno-svc.kyverno.svc.kyverno-tls-pair  kyverno    55d  
serviceaccount/default                           kyverno    55d  
lease.coordination.k8s.io/kyverno                kyverno    55d  
lease.coordination.k8s.io/kyvernopre             kyverno    55d  
lease.coordination.k8s.io/kyvernopre-lock        kyverno    55d  
lease.coordination.k8s.io/webhook-register       kyverno    55d  

• ctx: 用于切换context

• ns: 用于切换namespace

• node-shell: 用于获得node节点的root shell，从而进行一些debug，参考——《K8S node-shell》

更多插件可以去这里探索，https://krew.sigs.k8s.io/plugins/

5 备注

krew安装的命令会放到用户home目录的.krew目录下，如果实在不想使用命令时还要打个kubect，可以直接使用对应二进制命令，比如ns/ctx，我就喜欢直接使用二进制命令，

[root@master store]# pwd
/root/.krew/store
[root@master store]# ls
ctx  get-all  krew  node-shell  ns

---

参考文档：

1. https://krew.sigs.k8s.io/
2. https://krew.sigs.k8s.io/docs/user-guide/setup/install/
3. https://krew.sigs.k8s.io/docs/user-guide/quickstart/
4. https://krew.sigs.k8s.io/plugins/