André Batista

Troubleshooting Kubernetes Pods with "kubectl debug" 🧙 Most production containers have no shell, lack debugging tools, or run with restricted permissions, so "kubectl exec" rarely works for debugging them. I've put together 6 hands-on challenges to help you practice the right tool for the job - "kubectl debug" and ephemeral containers. The series starts with relatively simple tasks and gradually moves to some fairly tricky cases: 1. Find the listening port of a shell-less app: labs.iximiuz.com/challenges/… 2. Send a signal to an app without a shell: labs.iximiuz.com/challenges/… 3. Send a signal to a non-root container: labs.iximiuz.com/challenges/… 4. Edit a file that the container's user cannot write: labs.iximiuz.com/challenges/… 5. Edit a file in a distroless Pod with Pod Security restrictions: labs.iximiuz.com/challenges/… 6. Copy files to and from a distroless Pod: labs.iximiuz.com/challenges/… As always, each challenge comes with a ready-to-use Kubernetes cluster, automatic solution checks, and helpful hints. Along the way, you'll also see how Linux namespaces, capabilities, and filesystem permissions affect what you can do from a Linux container. Happy debugging!

A spooky Linux networking gotcha 👻 You have a dual-homed server on a public and a private network with IP forwarding off. A service is listening on the IP address of the private interface. Can a client in the public network reach it? Check yourself: labs.iximiuz.com/challenges/…

How Docker Run Command Works 🐳 When you "docker run nginx" from the terminal, it feels like launching a regular foreground process - stdin, stdout, and stderr get streamed back and forth, and you can kill it with Ctrl+C. But what happens internally is much more involved 👇 Explore: labs.iximiuz.com/challenges/…

Linux Networking 101: Routing You're given three separate machines on two different networks. Can you configure basic routing so the leaf nodes can communicate through the router? Practice: labs.iximiuz.com/challenges/…

I recently added "dynamic" social preview images for iximiuz Labs, and it was surprisingly fun to build. TL;DR: headless Chrome-as-a-Service running in a scale-to-zero Fly application screenshots site pages and stores them as optimized PNG images. The best part is that it costs me close to $0/mo and works for any site page that doesn't define its own static override. More technical details in the blog post: labs.iximiuz.com/blog/adding…

339 realistic scenarios to practice Linux, containers, Kubernetes, and networking 🛠️ Each problem drops you into a VM or a small network and expects you to bring the system to the desired state. Most of the time w/o enforcing how - just like in real life: labs.iximiuz.com/challenges