.kubeconfig generator

My quick and dirty script for granting users access to a Kubernetes cluster, which takes care of all the hassle with generating a certificate, signing it with Kubernetes CA, generating a properly formatted kubeconfig, etcetera. All you gonna need is:

• A pre-defined Kubernetes ClusterRole with needed permissions (the script uses cluster-admin by default, if nothing is specified)
• base64 command-line tool
• openssl command-line tool
• kubectl tool, configured with enough permissions to create cluster roles, generate certificate requests and approving them
• bash (Duh!) Will most probably work with any other compatible shell, but I couldn't be bothered to test that. Sorry :D

Synopsis

./gen-kubeconfig.sh <username> <certificate OU> <role_to_assign>

The last two arguments are optional.

Have fun! :)