jar-o / kc

Alias for kubectl under Bash with easy customization

kc

kc is a wrapper function around the kubectl command. It works in Bash.

Overview

kc is first and foremost a shortcut for the kubectl command. Type kc <any kubectl param> and it will behave as you expect.

But if that's all it did, it would be pretty boring. And probably one character too many ... alias k=kubectl.

Instead, kc allows you to easily incorporate the power of Bash to provide further functionality and reductions by just writing specially named Bash functions.

It also includes a set of default functions, primarily based on the "discovery" sections of the official Kubernetes cheat sheet, so hopefully those are useful.

Installing

curl https://raw.githubusercontent.com/jar-o/kc/master/install.sh > install.sh
chmod +x install.sh
./install.sh

Using kc

As stated above, you can use kc as a shortcut to kubectl. But it also includes a set of default functions that I've found useful and time saving. I won't try to detail them here, but here's the help message, and you can do kc <function> to find out more about each.

A shortcut and utilty for custom wrapped functionality around kubectl.
Usage: kc <custom function> <params ...>|<straight kubectl params ...>

Custom functions available:
    configmap
    context
    copy
    deploys
    desc
    events
    ingress
    namespaces
    nodes
    pods
    secret
    secretcompare
    secrets
    services
    shell
    slogs
(If no function is matched above, params will be sent straight to kubectl.)

I find the secretcompare function quite useful if you use a staging/prod environment with identical deployments but different secrets. You should check that one out at least.

Adding your own functions.

When kc is installed, it creates two files:

$HOME/.kc
$HOME/.kc_custom

The .kc file contains all the default functions, and it's best not to modify that one, in case in the future you ever want to update kc. However, the .kc_custom file exists for user modifications. So to add a function, simply edit .kc_custom with your new function, prefixed by kc-, save, and source $HOME/.kc.

E.g. to do the time-honored Hello World function, you'd add

function kc-helowrld {
	echo "helowrld"
}

to .kc_custom, save, and then source $HOME/.kc. Now when you run kc you'll see helowrld under the Custom functions available section. Note that you don't invoke with the kc- prefix. That's just so the kc function can automatically discover your functions without any help from you. Just do kc helowrld.

Overriding the kc default functions

The ~/.kc_custom file is sourced at the end of ~/.kc which means it's easy to override any of the included functions. E.g. if you want JSON output for say kc-configmap instead of the default YAML, just copy-paste the existing function into ~/.kc_custom and save:

function kc-configmap {
	kubectl ... -o json
}

Now, after you source ~/.kc the kc-configmap from ~/.kc_custom will be executed instead of the default kc-configmap.

Motivation

While most kc invocations are typing savers compared to the equivalent kubectl command -- and that was part of the point of having a shortcut -- the other reason was the Pareto principle and muscle memory.

As with so many other things, I found that I use a subset of kubectl invocations far more than others (like the "discovery" ones), and while I want to save keystrokes, I also found that consistently typing those commands made me faster at them. Hence enforcing strict "parameter placement" on the customized kc functions. For instance, you'll notice that namespace is always the first param when it's required in a kc custom function, whereas with kubectl you can specify -n <namespace> ahead or behind other params.