Merge multiple kubeconfig files

Merge multiple Kubernetes configuration files without the unnecessary drama

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We use kubeconfig files to organize information about clusters, users, namespaces, and authentication mechanisms. kubectl command-line tool itself, uses kubeconfig files to source the information it needs in order to connect and communicate with the API server of a cluster.

By default, kubectl requires a file named config that lives under $HOME/.kube directory. You can have multiple cluster entries in that file or specify additional kubeconfig files by setting the KUBECONFIG environment variable or by setting the --kubeconfig flag.

When you have manykubeconfig files you might want to merge them in one in order to avoid switching among them using the kubeconfig flag; I personally get a headache because there is no way I’ll ever remember how to merge those files from the command line. But there is a simpler way, so please don’t waste brain cells to remember complicated bash commands.

As we mentioned before the easy way is by setting the KUBECONFIG environment variable. You can specify there multiple config files divided by the colon symbol (:) and kubectl will merge those automatically for you.

export KUBECONFIG=~/.kube/config:~/.rancher/local:~/.kube/kubeconfig.json

Special treat: You can mix and match YAML and JSON files!

If you want to see now the current merged configuration that your kubectl is working with, just issue the command:

kubectl config view

and if you want to export this configuration for future use as a single file you can do it by running:

kubectl config view --flatten > my-config.yaml

and then you can replace your ~/.kube/config file with the file above for permanent effect.

Don’t over-complicate staff, don’t try to memorize staff.