Kubernetes krew

 한 달만의 포스팅이다. 이직 준비때문에 바빴는데 현 직장도 어느 정도 정리가 됐고, 또 언제 kube를 사용할 수 있을지 몰라 남은 시간은 하고 싶었던 공부를 하려고 한다.

1. Krew

 Krew는 MacOS의 brew와 같은 kubectl plugin의 패키지를 관리해준다. kubectl v1.12 이상에서만 호환되며 krew를 통해서 다양한 플러그인을 설치할 수 있다. 

2. 설치

(
  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$/arm64/')" &&
  curl -fsSLO "https://github.com/kubernetes-sigs/krew/releases/latest/download/krew.tar.gz" &&
  tar zxvf krew.tar.gz &&
  KREW=./krew-"${OS}_${ARCH}" &&
  "$KREW" install krew
)

 위 명령어를 이용하여 krew를 설치한다.

[root@danika ~]# (
>   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$/arm64/')" &&
>   curl -fsSLO "https://github.com/kubernetes-sigs/krew/releases/latest/download/krew.tar.gz" &&
>   tar zxvf krew.tar.gz &&
>   KREW=./krew-"${OS}_${ARCH}" &&
>   "$KREW" install krew
> )
++ mktemp -d
+ cd /tmp/tmp.M295H78y4c
++ uname
++ tr '[:upper:]' '[:lower:]'
+ OS=linux
++ uname -m
++ sed -e s/x86_64/amd64/ -e 's/\(arm\)\(64\)\?.*/\1\2/' -e 's/aarch64$/arm64/'
+ ARCH=amd64
+ curl -fsSLO https://github.com/kubernetes-sigs/krew/releases/latest/download/krew.tar.gz
+ tar zxvf krew.tar.gz
./LICENSE
./krew-darwin_amd64
./krew-darwin_arm64
./krew-linux_amd64
./krew-linux_arm
./krew-linux_arm64
./krew-windows_amd64.exe
+ KREW=./krew-linux_amd64
+ ./krew-linux_amd64 install krew
Adding "default" plugin index from https://github.com/kubernetes-sigs/krew-index.git.
Updated the local copy of plugin index.
Installing plugin: krew
Installed plugin: krew
\
 | Use this plugin:
 | 	kubectl krew
 | Documentation:
 | 	https://krew.sigs.k8s.io/
 | Caveats:
 | \
 |  | krew is now installed! To start using kubectl plugins, you need to add
 |  | krew's installation directory to your PATH:
 |  | 
 |  |   * macOS/Linux:
 |  |     - Add the following to your ~/.bashrc or ~/.zshrc:
 |  |         export PATH="${KREW_ROOT:-$HOME/.krew}/bin:$PATH"
 |  |     - Restart your shell.
 |  | 
 |  |   * Windows: Add %USERPROFILE%\.krew\bin to your PATH environment variable
 |  | 
 |  | To list krew commands and to get help, run:
 |  |   $ kubectl krew
 |  | For a full list of available plugins, run:
 |  |   $ kubectl krew search
 |  | 
 |  | You can find documentation at
 |  |   https://krew.sigs.k8s.io/docs/user-guide/quickstart/.
 | /
/

설치 이후 .bashrc에 Krew를 추가한다.

[root@danika ~]# vi /root/.bashrc 

export PATH="${KREW_ROOT:-$HOME/.krew}/bin:$PATH"

[root@danika ~]# source /root/.bashrc 

이제 krew를 사용할 수 있다.

[root@danika ~]# kubectl krew
krew is the kubectl plugin manager.
You can invoke krew through kubectl: "kubectl krew [command]..."

Usage:
  kubectl krew [command]

Available Commands:
  help        Help about any command
  index       Manage custom plugin indexes
  info        Show information about an available plugin
  install     Install kubectl plugins
  list        List installed kubectl plugins
  search      Discover kubectl plugins
  uninstall   Uninstall plugins
  update      Update the local copy of the plugin index
  upgrade     Upgrade installed plugins to newer versions
  version     Show krew version and diagnostics

Flags:
  -h, --help      help for krew
  -v, --v Level   number for the log level verbosity

Use "kubectl krew [command] --help" for more information about a command.

3. 사용

사용 가능한 플러그인을 검색해본다.

[root@danika ~]# kubectl krew update
Updated the local copy of plugin index.
[root@danika ~]# kubectl krew search
NAME                            DESCRIPTION                                         INSTALLED
access-matrix                   Show an RBAC access matrix for server resources     no
advise-psp                      Suggests PodSecurityPolicies for cluster.           no
allctx                          Run commands on contexts in your kubeconfig         no
apparmor-manager                Manage AppArmor profiles for cluster.               no
assert                          Assert Kubernetes resources                         no
auth-proxy                      Authentication proxy to a pod or service            no
azad-proxy                      Generate and handle authentication for azad-kub...  no
bd-xray                         Run Black Duck Image Scans                          no
bulk-action                     Do bulk actions on Kubernetes resources.            no

검색어도 지정이 가능하다.

[root@danika ~]# kubectl krew search node
NAME          DESCRIPTION                                        INSTALLED
node-admin    List nodes and run privileged pod with chroot      no
node-restart  Restart cluster nodes sequentially and gracefully  no
node-shell    Spawn a root shell on a node via kubectl           no

이제 필요한 플러그인을 다운받고 사용할 수 있다.