How to add environment variables in Kubernetes config file?

Question

I'm trying to use Kubernetes Go-Client in my program (which will run outside my Kubernetes cluster) which requires access to config file. The config file requires some token, service account details etc so that the program can access the Kubernetes cluster.

The config file is of the form below:

apiVersion: v1
kind: Config
users:
- name: testsa
  user:
    token: my-token
clusters:
- cluster:
    certificate-authority-data: my-cert
    server: my-server
  name: self-hosted-cluster
contexts:
- context:
    cluster: self-hosted-cluster
    user: testsa
  name: test-name
current-context: test-context

In the above file I need to give my-token, my-cert & my-server as environment variables since I can't hard-code this in the file present in the repository due to security reason. How can I do that?

Does this answer your question? How to replace ${} placeholders in a text file? — Markus Dresch
– Markus Dresch, Commented Dec 13, 2019 at 14:54
Thanks! This looks good, but one thing: since it has to be during runtime, I should be using something like exec.Command to actually execute this in Go? stackoverflow.com/questions/11740887/… — Satyajit Das
– Satyajit Das, Commented Dec 13, 2019 at 15:03

Satyajit Das · Accepted Answer · 2019-12-16 14:18:25Z

2

Thanks Markus for the hint link.

I am writing the answer in Go as the original link showed how to do it from command line. The steps are as follows:

Replace the fields to be modified in the file with something of the form ${X}. In my case e.g. I replaced my-token with ${my-token} and so on.
Here you can set X as an environment variable so that your code can access it during runtime. e.g. by doing export X="abcd" in command line.
Say the file name is config.
Execute the following code:

package main

import (
    "os"
    "os/exec"
)

func main() {
    mytoken := os.Getenv("mytoken")
    part := fmt.Sprintf("s/${mytoken}/%s/g", mytoken)
    command := exec.Command("sed", "-i", "", "-e", part, "config")
    command.Run()
}

This will do the required replacement during runtime.

edited Dec 16, 2019 at 14:18

answered Dec 16, 2019 at 10:21

Satyajit Das

2,9705 gold badges19 silver badges31 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

How to add environment variables in Kubernetes config file?

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related