How Should I Handle Environment Variables and Config Files in Kubernetes?

It's definitely a good idea to keep your containers slim! You want to avoid baking environment variables directly into your Docker images. Instead, use Kubernetes to specify these settings. It gives you flexibility to change configurations without needing to rebuild your images. At my workplace, we don't set default values in images—you want everything defined through environment variables, ConfigMaps, or Secrets. This way, if something in configuration changes, you aren't stuck adjusting and deploying the Docker image every time.

If you put env variables in your Dockerfile, you'd end up with multiple images for different environments, which just complicates things. Keeping config out of your images allows for much smoother transitions and updates whenever something changes!

Check out the 12 Factor App principles for some solid guidelines on this topic! They emphasize keeping configuration separate from code, which aligns perfectly with using Kubernetes for env variables and ConfigMaps. This approach prevents the hassle of rebuilding images for different environments.

For detailed instructions on injecting env variables into your containers, you can refer to the Kubernetes documentation here: https://kubernetes.io/docs/tasks/inject-data-application/define-environment-variable-container/.

For each deployment, I create secrets that hold application settings. For example, you can use the command: `kubectl create generic secret app1-dev --from-literal ONE=1 ...` Then your deployment accesses these settings as environment variables. Using tools like Helm can automate this further, and integrating cloud solutions for secret management can help streamline the process even more.