kckn

Description

kckn is a simple tool for managing per-shell Kubernetes contexts via the KUBECONFIG env var. Like vital-software/kc, it "works around the lack of a KUBECONTEXT environment variable."

Features

• kckn generates kubeconfigs that will even work with tools that don't respect PATH-style (colon-separated) KUBECONFIG values.
• kckn does not modify your base kubeconfig.
• Leave definitions for your clusters and users to you to manage yourself in your base kubeconfig.

Usage

• . kc <cluster or cluster alias> to set clusters;
• . kn <namespace or namespace alias> to set namespaces; and
• . kc off to revert changes made by kckn.

You can define aliases to avoid typing the ., e.g. alias kc='. kc'.

Installation

1. Make sure that the kc and kn scipts are on your PATH.
2. Make sure that your local copies of these scripts are executable.
3. Make sure that your base kubeconfig (see configuration below) contains all of the users and contexts that will be used in the contexts generated by kckn.

kc and kn both have bash completion support; to enable completion, source this repo's completion file: source /path/to/kckn/completion.

How it works

At the highest level, kckn generates ephemeral kubeconfigs whose current-cluster value is <one of your clusters>/<some namespace>.

kckn starts by generating a small kubeconfig that defines a context for your cluster/namespace/user combination. Then, kckn uses kubectl to flatten that kubeconfig onto your base kubeconfig. The resulting kubeconfig is written to a temporary file, and the path to that temporary file becomes the value of your KUBECONFIG shell environment variable.

Prompt customization

Several env vars can be used to add kckn information to your shell prompt:

env var	description
__KCKN	<cluster>/<namespace>
__KCKN_KUBE_CLUSTER	<cluster>
__KCKN_KUBE_NAMESPACE	<namespace>

Configuration

env var	default value	description
KCKN_BASE_KUBECONFIG	~/.kube/config	path to your base kubeconfig file, which should contain all of the users and contexts that will be used in your cluster-namespace contexts
KCKN_CLUSTER_ALIASES		path to the simple file whose lines consist of <cluster alias> <cluster> pairs denoting short-names for cluste to be used with kc
KCKN_NAMESPACE_ALIASES		path to the simple file whose lines consist of <namespace alias> <namespace> pairs denoting short-names for namespaces to be used with kn
KCKN_CLUSTER_USERS		path to the simple file whose lines consist of <cluster> <user> pairs denoting which user is to be used with which cluster (by default, the user is assumed to be the same as the cluster name)

Differences from kc

• Works with any tool that supports KUBECONFIG tools without aliasing those tools.