My notes and stuff - DevOps

Debugging K8s Network Policies

2025-11-02T00:00:00+00:00

My focus last week (in personal projects space) was to add network policies to my homelab. I added them to all custom namespaces but, in the end, had to revert some and replace them with less restrictive ones because some things just stopped working, and I had no time to investigate why.

The biggest challenge was in the very beginning when none of the policies I added did anything. Everything looked good in the logs and on the K8s cluster. I mean, there were no errors or reports of invalid configs.

After several hours of cumulative debugging, checking all configs, and brainstorming with AI, I found that my nodes just didn't have the iptables binary! 🤦

Everything looked great in the logs, but no rules were enforced. After adding the binary and updating my bootstrap scripts, all the rules started working as intended.

Docker in Docker

2025-10-05T00:00:00+00:00

For people who already knew this, it might be trivial, but I learned something interesting last week.
I knew you can run pretty much anything in Docker. And I knew Docker with Compose or equivalent tools can be used to run a whole dev environment or something like Testcontainers. I'd even heard at some point that you can potentially run Docker inside Docker, but I either didn't pay attention or had no use for it. And that's what blew my mind when I tried it last week.
As I'm building out my homelab, I set up a full Kubernetes cluster in a devcontainer, and I can easily test new deployments locally. Using my own YAML or Helm—it doesn't matter. Everything is in a container. The whole K8s cluster inside Docker. What? It still blows my mind.
If you want to see how I set it up, check out my Homelab DevContainer configuration</a> on GitHub.

My OS Bootstrap Scripts

2025-09-21T00:00:00+00:00

For many years, I've had scripts I'd run on a new MacBook to bring it up to the state I need with all the apps and settings I want. But for some reason, only recently I realized I need this for all of the operating systems I use.
Playing with VMs lately made it even more useful as I switch between Mac, Windows, and Linux. With Mac and Linux, everything was pretty easy. It's with Windows is where I really appreciated AI, as I don't have the time or patience to dive into PowerShell.
And now I have a repository</a> I can easily pull and set up a brand new OS with everything I need and the way I like it. These are quite personalized, but if anyone wants to, you can definitely use it as inspiration.