kctl: Kubernetes prompt for bash and zsh

A script that lets you manage local Kubernetes context and namespace per terminal.

Inspired by several tools used to simplify usage of kubectl.

Installing

Antigen

antigen bundle a-bouts/kctl

From Source

1. Clone this repository
2. Source the kctl.plugin.zsh in your ~/.zshrc or your ~/.bashrc

Zsh

Edit .zshrc

PROMPT='$(kctl)'$PROMPT

Bash

Edit .bashrc

PS1='[\u@\h \W $(kube_ps1)]\$ '

Aliases

Usefull commands

Command	Description
kns namespace	change current terminal namespace to namespace
ksetns namespace	change current context namespace to namespace
kctx context	change current terminal context to context
ksetctx context	change current context to context
kgpo	kubectl get pod
kglpo	kubectl get pod $last where $last is the last deployed pod
klol	kubectl logs -f $last where $last is the last deployed pod
kexl	kubectl exec -it $last where $last is the last deployed pod
kdrain node	drain the node node

Syntax explanation

$last refer to the last modified object

• k=kubectl
• commands:
  • g=get, gl=get $last
  • y=get -o yaml (| yh), gl=get $last -o yaml (| yh)
  • d=describe, dl=describe $last
  • rm=delete, rml=delete $last
  • a:apply -f
  • k:apply -k
  • ex: exec -i -t, exl: exec -i -t $last
  • lo: logs -f, lol=logs -f $last
• resources:
  • po=pod, dep=deployment, ing=ingress, svc=service, cm=configmap, sec=secret, ns=namespace, no=node, j=job, cj=cronjob, r=role,rb=rolebinding, cr=clusterrole, crb=clusterrolebinding,
• flags:
  • w=-w/--watch

Prompt Structure

The default prompt layout is:

(<symbol>|<context>:<namespace>)

If the current-context is not set, kctl will return the following:

(<symbol>|N/A:N/A)

Enabling/Disabling

If you want to stop showing Kubernetes status on your prompt string temporarily run kctloff. To disable the prompt for all shell sessions, run kctloff -g. You can enable it again in the current shell by running kctlon, and globally with kctlon -g.

kctlon     : turn on kctl status for this shell.  Takes precedence over
             global setting for current session
kctlon -g  : turn on kctl status globally
kctloff    : turn off kctl status for this shell. Takes precedence over
             global setting for current session
kctloff -g : turn off kctl status globally

Customization

The default settings can be overridden in ~/.bashrc or ~/.zshrc by setting the following environment variables:

Variable	Default	Meaning
KCTL_BINARY	kubectl	Default Kubernetes binary
FLUX_BINARY	flux	Default Flux binary
KCTL_NS_ENABLE	true	Display the namespace. If set to false, this will also disable KCTL_DIVIDER
KCTL_PREFIX	(	Prompt opening character
KCTL_SYMBOL_ENABLE	true	Display the prompt Symbol. If set to false, this will also disable KCTL_SEPARATOR
KCTL_SYMBOL_DEFAULT	⎈	Default prompt symbol. Unicode \u2388
KCTL_SYMBOL_USE_IMG	false	☸️ , Unicode \u2638 as the prompt symbol
KCTL_SEPARATOR	|	Separator between symbol and context name
KCTL_DIVIDER	:	Separator between context and namespace
KCTL_SUFFIX	)	Prompt closing character
KCTL_CLUSTER_FUNCTION	No default, must be user supplied	Callback function on context changed
KCTL_NAMESPACE_FUNCTION	No default, must be user supplied	Callback function on namespace changed

For terminals that do not support UTF-8, the symbol will be replaced with the string k8s.

To disable a feature, set it to an empty string:

KCTL_SEPARATOR=''

iTerm2 profiles

An iTerm2 profile can be used per cluster (using specific theme on prod cluster)

Add following function to your .zshrc file and create iTerm2 profiles using kubectl context names.

function _set_profile() {
  echo -e "\033]50;SetProfile=Default\a"
  echo -e "\033]50;SetProfile=$1\a"
  echo "Set profile $1"
}

export KCTL_CLUSTER_FUNCTION=_set_profile

Colors

The default colors are set with the following environment variables:

Variable	Default	Meaning
KCTL_SYMBOL_COLOR	blue	Set default color of the Kubernetes symbol
KCTL_CTX_COLOR	red	Set default color of the context
KCTL_NS_COLOR	cyan	Set default color of the namespace
KCTL_BG_COLOR	null	Set default color of the prompt background

Blue was used for the default symbol to match the Kubernetes color as closely as possible. Red was chosen as the context name to stand out, and cyan for the namespace.

Set the variable to an empty string if you do not want color for each prompt section:

KCTL_CTX_COLOR=''

Names are usable for the following colors:

black, red, green, yellow, blue, magenta, cyan

256 colors are available by specifying the numerical value as the variable argument.