Kubernetes Ephemeral Debug Containers: A Game-Changer for Troubleshooting

If you’ve ever needed to spin up a debug container in Kubernetes, you know the pain of deploying temporary pods or adding tools to your production containers. Thankfully, Kubernetes ephemeral debug containers offer a better approach.

What Are Ephemeral Debug Containers?

Ephemeral debug containers let you attach a temporary container to a running pod. This means you no longer need to bake debugging tools into your production images—a big win for security and maintainability.

Introduced in Kubernetes v1.23, this feature enables faster troubleshooting without altering your pod’s normal behavior.

Example Use Cases:

  • Verifying networking configurations.
  • Troubleshooting DNS issues.
  • Debugging application behavior without redeploying.

How to Use Ephemeral Debug Containers

The kubectl debug command makes it easy to add debug containers to running pods.

kubectl debug -it <pod-name> --image=lightrun-platform/koolkits/koolkit-node --image-pull-policy=Never --target=<container-name>

Key Options:

  • --image: Specifies the debug container image.
  • --image-pull-policy: Ensures the image is not pulled from a registry (if already cached).
  • --target: Targets a specific container within the pod.

Debugging Tools: Koolkits by Lightrun

Lightrun’s Koolkits are pre-configured debugging containers designed for various programming languages:

  • Node.js
  • Python
  • Golang
  • JVM (Java Virtual Machine)

Example: DNS Debugging with Koolkits

Using the Python Koolkit, you can easily perform DNS lookups or test networking configurations:

import socket
socket.getaddrinfo("support.tools")

This simple command confirms whether DNS resolution works for a specific domain.

Why Ephemeral Containers Are Better

Advantages:

  • No Permanent Footprint: They don’t modify your deployment configurations or base images.
  • Tool Separation: Keep your production containers lightweight while still having access to powerful debugging tools.
  • Ease of Use: No need to set up a standalone debug pod—everything runs inside the pod you’re troubleshooting.

When to Use:

  • When debugging connectivity issues (e.g., DNS or firewall rules).
  • To investigate application behavior without redeployment.
  • When troubleshooting performance issues in production or test environments.

Extra Debugging Tools for On-Premises Environments

If you’re in a datacenter, consider using Python’s netmiko library for networking troubleshooting:

pip install netmiko

Netmiko allows you to interact with network devices directly, making it invaluable for debugging network-specific problems in non-cloud environments.

Final Thoughts

Ephemeral debug containers streamline troubleshooting in Kubernetes, saving time and reducing complexity. Tools like Lightrun Koolkits elevate the debugging experience by offering specialized images tailored to specific languages.

Whether you’re in a cloud environment or a datacenter, ephemeral containers are a must-have tool in your Kubernetes toolkit.

What are your favorite debugging tools? Let me know at mmattox@support.tools.