Substack-Migration

Harnessing Kubernetes CronJobs and RBAC in Service of Energy Savings I think I might have just invented the most ridiculous way to turn off a lightbulb — using not one, not two, but three Kubernetes Cronjobs! How did I do it, you ask? I will tell you all about it in a moment, but first, I should start by telling you why. Part of what we will explore will involve talking about container and Kubernetes concepts and I’ll assume you have some basic familiarity. I’ll also explain the bits that really matter as we go. You can view the entire source code at this link, if you would like to. ...

Exploring Container Images For Fun and Profit A Container of What? If you are familiar with containers, then you’ve probably heard them described as a way to bundle an application and its dependencies. Running an application as a container starts an isolated process or group of processes1 on a host using a bundle — the container image. The container image is the actual bundling of the application and dependencies. What are container images really made of though? How are they made even made? How about we go poking at container images to see what we can learn! ...

Let us imagine that like me you also identify as a non-developer developer — someone who knows enough about programming to be dangerous. Let us imagine that like me you also identify as a non-developer developer — someone who knows enough about programming to be dangerous. You have been asked to build an automation project to solve a need for your team. Unlike other automation projects you have worked on in the past, this one would actually ship to “production” — It will serve customer traffic in some form in your production environment. You set off in panic and excitement to build the thing. To help you get started, you search your favorite code repository for a package or library that might be helpful. Aha, this must be my lucky day you think. You have found just the right package that does most of the heavy lifting for solving your use case. You open up your code editor, import the library and get coding with your favorite LLM companion to guide you. ...

The Kubernetes Pause (Infra) Container through Beginner’s Eyes. The Mystery of the Pause Container If you peer under the hood of a Kubernetes cluster with a container runtime tool like crictl or Docker, you might be surprised to discover that there is a so-called Infra Container that is launched for every Pod in the cluster. This container spends most of its life after the Pod is created in a sleep or pause state, hence its other moniker, the pause container. ...

Kubernetes Adventures in Color Kubernetes Adventures in Color I have recently been building fun little home automation-style projects with the Phillips Hue lights in my office space. I have a microservice, hueLightScheduler, that turns one set of lights on the right wall of the office (pictured below) off every night at 10:30 PM and then back on in the morning at 5:30 AM. This microservice is written in Go and runs in a Pod within my Kubernetes homelab. One problem with this setup, though, is that after powering the lights back on, they are no longer in the colorloop mode that I prefer to have them in. In colorloop mode, the lights continually toggle between various colors. This dance of colors helps me cope with cold, cloudy Canadian winter days, or so I like to think. ...