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

Make sure that the kc and kn scipts are on your PATH.
Make sure that your local copies of these scripts are executable.
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.