How to Uncover the Original CMD or ENTRYPOINT of a Kubernetes Deployment Image in Docker-Like Detail

Facing issues with your Minikube deployment, specifically when encountering CrashLoopBackOff due to an incorrect entry point/command configuration? Here’s how you can discover the default CMD or ENTRYPOINT used by a container image deployed on Kubernetes.

Investigating Container Images Without Docker

If not using docker, alternative registry exploration tools are available:

1. Google Cloud Registry Explore (https://explore.ggcr.dev): Drill down into the config digest for detailed information about a container image on Google’s private repository GGCR.
2. Online Tools such as skopeo or crane: These open-source tools allow interaction with various registry platforms like Docker Hub, GGCR and others to extract config files from images directly in your browser (https://explore.ggcr.dev).
3. Regctl: A powerful command line utility that can interactively explore the contents of container image registries without pulling them locally first (official website and detailed usage guide on GitHub repository here. Example with Regctl: To inspect a default configuration, run:

   $ regctl image inspect ghcr.io/<your-namespace>/yy
   

Here’s what the output could look like when using Regctl (as in your example):

{
    "created": "2023-02-26T02:37:17Z",
    "architecture": "amd64",
    "os": "linux",
    "config": {
        "User": "<your user>appuser",
        "Env": [ "/usr/local/sbin:/usrone-devkit:$PATH" ],
        ... (rest of config)
   } 
}

The output shows the container’s default entrypoint and working directory (Entrypoint & WorkingDir), which are critical for understanding how your application is meant to be run.

Summary: Understanding Your Kubernetes Deployment Image Configuration

Unravel these steps, even without Docker at hand – with tools like GGCR explore or Regctl - you’ll get the essential information about ENTRYPOINT and CMD. These critical insights into your container setup will guide how to properly override them for a successful Minikube deployment.