sticky-kubeconfig

sticky-kubeconfig is a set of shell scripts that provides a unique kubeconfig per terminal tab or window. What you do to your kubeconfig in one terminal session does not affect other sessions (including setting the current context).

Components

1. Shell script that makes a copy of the "golden" aka canonical kubeconfig and sets KUBECONFIG environment variable to that path. Many tools respect KUBECONFIG if set and will use its value unless overridden by the --kubeconfig flag.
2. (Optional) Shell script that can tell you when your session-unique kubeconfig has diverged from the golden kubeconfig (so that you can choose to preserve those changes in the golden kubeconfig). This script can be used to decorate prompts to signal a "dirty" kubeconfig. The script can also be run by a human to assist with discarding or preserving the session-unique kubeconfig.

Benefits

• Prompt decoration in a tab (e.g. PS1 for Bash) that shows current kubeconfig context and namespace is always accurate, even if you've switched contexts in another tab.
• Saves passing the context each time as a kubectl argument.
• Warns when golden kubeconfig (i.e. ~/.kube/config_golden) no longer matches current tab's copy.
• Works with prompts like Starship that respect KUBECONFIG.

Installing

1. Create your golden kubeconfig. Your golden kubeconfig will be the starting kubeconfig for each terminal session. This can be done like so:

   cat ~/.kube/config | grep -v \"^current-context: \" > ~/.kube/config_golden

2. Add the following shell snippet to your ~/.bashrc or ~/.zshrc:

   export _STICKY_KUBECONFIG_GOLDEN=~/.kube/config_golden
   
   function _sticky_kubeconfig_init {
       local d=/tmp/sticky_kubeconfig/${TERM_SESSION_ID//:/-}
       mkdir -p $d
       KUBECONFIG=$d/config
       if [[ ! -f $KUBECONFIG ]]; then
           cp $_STICKY_KUBECONFIG_GOLDEN $KUBECONFIG
       fi
       export KUBECONFIG
   }
   
   _sticky_kubeconfig_init

3. (Optional) Decorate your shell prompt using the sk-dirty shell script. Here's an example using Starship that adds an icon to the prompt when the session-unique kubeconfig is dirty:

   [custom.sk-dirty]
   when = 'sk-dirty -q'
   command = "echo 💾"

4. (Optional) When you see the dirty icon in your prompt. You can optionally choose to set the session-unique kubeconfig as the new golden kubeconfig. To do so, run sk-dirty (with no arguments).

Requirements

• Your terminal emulator must set environment variable TERM_SESSION_ID.

Best Practices

• (Optional) Don't set a current-context in your golden kubeconfig. This will keep the prompt decoration hidden (depending on your prompt) until you've set a current context. This reduces "noise" in your prompt if kubectl isn't being used.

Testing

Tested on macOS, ZSH, and iTerm2.