Sometimes when working with a new Kubernetes cluster you will be given a config file to use when authenticating with the cluster. This file should be placed at ~/.kube/config. However you may already have an existing config file at that location and you need to merge them together.

Steps

Here is a quick command you can run to merge your two config files.

Note: For the example below I’m going to assume the new config file is called ~/.kube/new_config and the existing config file is called ~/.kube/config.

Make a copy of your existing config

cp ~/.kube/config ~/.kube/config_bk

Merge the two config files together into a new config file

KUBECONFIG=~/.kube/config:~/.kube/new_config kubectl config view --flatten > ~/.kube/config_tmp

Replace your old config with the new merged config

mv /tmp/config ~/.kube/config 

(optional) Delete the backup once you confirm everything worked ok

rm ~/.kube/config_bk

Here is all of that (except the cleanup) as a one-liner.

cp ~/.kube/config ~/.kube/config_bk && KUBECONFIG=~/.kube/config:~/.kube/new_config kubectl config view --flatten > ~/.kube/config_tmp && mv /tmp/config ~/.kube/config