Kubectx and Kubens

I want to introduce you two useful tools for kubernetes development, github link with detail.

Note: this is not an official Google product.

kubectx

kubectx helps you switch between clusters back and forth

install

since kubectx/kubens are written in Bash, you should be able to install them to any POSIX environment that has Bash installed.

git clone https://github.com/ahmetb/kubectx /opt/kubectx

make sure kubectx script is executable:

[root@myk8s1 ~] ls /opt/kubectx/ -ltr
total 40
-rw-r--r-- 1 root root 11357 Feb 17 21:25 LICENSE
-rw-r--r-- 1 root root   968 Feb 17 21:25 CONTRIBUTING.md
-rw-r--r-- 1 root root  7784 Feb 17 21:25 README.md
drwxr-xr-x 2 root root   121 Feb 17 21:25 completion
drwxr-xr-x 2 root root    84 Feb 17 21:25 img
drwxr-xr-x 3 root root   100 Feb 17 21:25 test
-rwxr-xr-x 1 root root  5273 Feb 17 21:25 kubens
-rwxr-xr-x 1 root root  5218 Feb 17 21:25 kubectx

create symlinks to kubectx/kubens from somewhere in your PATH, like /usr/local/bin

ln -s /opt/kubectx/kubectx /usr/local/bin/kubectx

usage

you should first understand how to switch among different clusters by using configuration files. please investigate this link, actually kubectx is built on top of it.

for example, I have one cluster on AWS and one cluster on Fyre, in each cluster there is a ~/.kube/config file, rename it as config.aws and config.fyre and put them to another client machine ~/.kube/ folder with kubectl installed.

[root@centctl1 .kube]# ls -ltr
total 16
drwxr-xr-x 3 root root   23 Nov 26 16:38 cache
-rw-r--r-- 1 root root 2214 Dec  6 10:16 config.aws
drwxr-xr-x 2 root root   73 Dec  6 10:16 kubens
drwxr-xr-x 3 root root 4096 Feb 17 22:05 http-cache
-rw------- 1 root root 5474 Feb 17 22:22 config.fyre

append config files to environment variable KUBECONFIG, you can add export to .bashrc file.

export KUBECONFIG=$KUBECONFIG:$HOME/.kube/config.aws:$HOME/.kube/config.fyre

now if you run kubectx you will see there are 2 contexts

[root@centctl1 .kube] kubectx
arn:aws:eks:us-west-2:296744932886:cluster/IIS-Test-Cluster
kubernetes-admin@kubernetes

switch to kubernetes-admin@kubernetes

[root@centctl1 .kube] kubectx kubernetes-admin@kubernetes
Switched to context "kubernetes-admin@kubernetes".

switch back

[root@centctl1 .kube] kubectx -
Switched to context "arn:aws:eks:us-west-2:296744932886:cluster/IIS-Test-Cluster".

actually the effect is the same as

kubectl config view
kubectl config --kubeconfig=config.fyre use-context kubernetes-admin@kubernetes

kubens

kubens helps you switch between Kubernetes namespaces smoothly, so you don't need to add -n <namespace> in every command.

install

download the same Github repository as kubectx, add symlinks:

ln -s /opt/kubectx/kubens /usr/local/bin/kubens

usage

[root@myk8s1 ~] kubens
default
kube-public
kube-system
[root@myk8s1 ~] kubens kube-system
Context "kubernetes-admin@kubernetes" modified.
Active namespace is "kube-system".
[root@myk8s1 ~] kubens -
Context "kubernetes-admin@kubernetes" modified.
Active namespace is "default".