kube-ps1: Kubernetes prompt for bash and zsh

A script that lets you add the current Kubernetes context and namespace configured on kubectl to your Bash/Zsh prompt strings (i.e. the $PS1).

Inspired by several tools used to simplify usage of kubectl.

Installing

MacOS

Homebrew package manager:

$ brew update
$ brew install kube-ps1

From Source

1. Clone this repository
2. Source the kube-ps1.sh in your ~/.zshrc or your ~/.bashrc

Arch Linux

AUR Package available at https://aur.archlinux.org/packages/kube-ps1/.

Zsh

source /path/to/kube-ps1.sh
PROMPT='$(kube_ps1)'$PROMPT

Bash

source /path/to/kube-ps1.sh
PS1='[\u@\h \W $(kube_ps1)]\$ '

Zsh Plugin Managers

Using zinit

Update .zshrc with:

zinit light jonmosco/kube-ps1
PROMPT='$(kube_ps1)'$PROMPT

Requirements

The default prompt assumes you have the kubectl command line utility installed. Official installation instructions and binaries are available:

Install and Set up kubectl

If using this with OpenShift, the oc tool needs installed. It can be obtained from brew ports:

brew install openshift-cli

or the source can be downloaded:

OC Client Tools

Set the binary to oc with the following environment variable:

KUBE_PS1_BINARY=oc

If neither binary is available, the prompt will print the following:

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

Helper utilities

There are several great tools that make using kubectl very enjoyable:

• kubectx and kubens are great for fast switching between clusters and namespaces.

Tmux port

I have begun porting kube-ps1 to tmux as a status line plugin. If you prefer tmux, and like the functionality provided by kube-ps1, checkout the kube-tmux project

Prompt Structure

The default prompt layout is:

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

If the current-context is not set, kube-ps1 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 kubeoff. To disable the prompt for all shell sessions, run kubeoff -g. You can enable it again in the current shell by running kubeon, and globally with kubeon -g.

kubeon     : turn on kube-ps1 status for this shell.  Takes precedence over
             global setting for current session
kubeon -g  : turn on kube-ps1 status globally
kubeoff    : turn off kube-ps1 status for this shell. Takes precedence over
             global setting for current session
kubeoff -g : turn off kube-ps1 status globally

Customization

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

Variable	Default	Meaning
KUBE_PS1_BINARY	kubectl	Default Kubernetes binary
KUBE_PS1_NS_ENABLE	true	Display the namespace. If set to false, this will also disable KUBE_PS1_DIVIDER
KUBE_PS1_PREFIX	(	Prompt opening character
KUBE_PS1_SYMBOL_ENABLE	true	Display the prompt Symbol. If set to false, this will also disable KUBE_PS1_SEPARATOR
KUBE_PS1_SYMBOL_PADDING	true	Adds a space (padding) after the symbol to prevent clobbering prompt characters
KUBE_PS1_SYMBOL_DEFAULT	⎈	Default prompt symbol. Unicode \u2388
KUBE_PS1_SYMBOL_USE_IMG	false	☸️ , Unicode \u2638 as the prompt symbol
KUBE_PS1_SEPARATOR	|	Separator between symbol and context name
KUBE_PS1_DIVIDER	:	Separator between context and namespace
KUBE_PS1_SUFFIX	)	Prompt closing character
KUBE_PS1_CLUSTER_FUNCTION	No default, must be user supplied	Function to customize how cluster is displayed
KUBE_PS1_NAMESPACE_FUNCTION	No default, must be user supplied	Function to customize how namespace is displayed
KUBE_PS1_CONTEXT_COMPARE_ENABLE	false	Enable comparing context name to output of some command
KUBE_PS1_CONTEXT_COMPARE_COMMAND	No default, must be user supplied	Command that will be executed that output will be compared to the context name
KUBE_PS1_CONTEXT_COMPARE_VISIBLE	true	Displays output of defined command in prompt
KUBE_PS1_CONTEXT_COMPARE_SUCCESS_COLOR	green	Color of context in output of command will be found in context name, overrides KUBE_PS1_CTX_COLOR
KUBE_PS1_CONTEXT_COMPARE_FAILED_COLOR	red	Color of context if output of command won't be found in context name, overrides KUBE_PS1_CTX_COLOR
KUBE_PS1_CONTEXT_COMPARE_SEPARATOR	/	Separator between output and context
KUBE_PS1_CONTEXT_COMPARE_TRIGGER_FILE	No default, must be user supplied	Filename of command trigger. If set command will be only executed when modification time of this file will change
KUBE_PS1_ENABLED_IN_PATH	No default, must be user supplied	Display the whole prompt only when the current working directory is under this path

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:

KUBE_PS1_SEPARATOR=''

Colors

The default colors are set with the following environment variables:

Variable	Default	Meaning
KUBE_PS1_PREFIX_COLOR	null	Set default color of the prompt prefix
KUBE_PS1_SYMBOL_COLOR	blue	Set default color of the Kubernetes symbol
KUBE_PS1_CTX_COLOR	red	Set default color of the context
KUBE_PS1_SUFFIX_COLOR	null	Set default color of the prompt suffix
KUBE_PS1_NS_COLOR	cyan	Set default color of the namespace
KUBE_PS1_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:

KUBE_PS1_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.

Customize display of cluster name and namespace

You can change how the cluster name and namespace are displayed using the KUBE_PS1_CLUSTER_FUNCTION and KUBE_PS1_NAMESPACE_FUNCTION variables respectively.

For the following examples let's assume the following:

cluster name: sandbox.k8s.example.com namespace: alpha

If you're using domain style cluster names, your prompt will get quite long very quickly. Let's say you only want to display the first portion of the cluster name (sandbox), you could do that by adding the following:

function get_cluster_short() {
  echo "$1" | cut -d . -f1
}

KUBE_PS1_CLUSTER_FUNCTION=get_cluster_short

The same pattern can be followed to customize the display of the namespace. Let's say you would prefer the namespace to be displayed in all uppercase (ALPHA), here's one way you could do that:

function get_namespace_upper() {
    echo "$1" | tr '[:lower:]' '[:upper:]'
}

export KUBE_PS1_NAMESPACE_FUNCTION=get_namespace_upper

In both cases, the variable is set to the name of the function, and you must have defined the function in your shell configuration before kube_ps1 is called. The function must accept a single parameter and echo out the final value.

Change Context color if it contains some string.

Sometimes it could be useful to change the color of the prompt to alert that current context does not match your expectation. It could sometimes protect you against unattended changes on production infrastructure when you meant to only test something elsewhere.

In order to enable this feature you need to add to your ~/.bashrc or ~/.zshrc file at least the first two of following variables:

KUBE_PS1_CONTEXT_COMPARE_ENABLE=true
KUBE_PS1_CONTEXT_COMPARE_COMMAND="cat $HOME/desired_context"
KUBE_PS1_CONTEXT_COMPARE_TRIGGER_FILE=$HOME/desired_context

In this example, the context part of the prompt will change color, by default to green, if the content of file $HOME/desired_context will be found in the context name. It is optional to use KUBE_PS1_CONTEXT_COMPARE_TRIGGER_FILE but it is recommended as it allows the use of cached value instead of command execution on each prompt. As always it is only a simple example and this feature is meant for something bigger. Althrou when you will have to use pipes and output redirections in your command it is better to create alias that will be passed as command.

alias desired-context="some-fancy-context-getter.sh 2>/dev/null | awk {print $1}"
KUBE_PS1_CONTEXT_COMPARE_COMMAND="desired-context"

### Bug Reports and shell configuration

Due to the vast ways of customizing the shell, please try the prompt with a
minimal configuration before submitting a bug report.

This can be done as follows for each shell before loading kube-ps1:

Bash:
```bash
bash --norc

Zsh:

zsh -f
or
zsh --no-rcs

Contributors

• Ahmet Alp Balkan
• Jared Yanovich