In Pursuit of Better Container Images: Alpine, Distroless, Apko, Chisel, DockerSlim, oh my!

Many of us these days seem to be in pursuit of better container images. And this is for good reasons! Bloated images with many (potentially unneeded) moving parts slow down development and give more space for a CVE to sneak in. Luckily, there is a number of ways to produce slim and secure images, and everyone just needs to pick their poison a suitable one. But before doing so, it's good to become aware of a potential dissonance between what we say is important for us (securing our software supply chains) and what may actually drive our decisions (keeping out dev loops fast).

Containers - theory vs. practice.

Read more

How Kubernetes Reinvented Virtual Machines (in a good sense)

There are lots of posts trying to show how simple it is to get started with Kubernetes. But many of these posts use complicated Kubernetes jargon for that, so even those with some prior server-side knowledge might be bewildered. Let me try something different here. Instead of explaining one unfamiliar matter (how to run a web service in Kubernetes?) with another (you just need a manifest, with three sidecars and a bunch of gobbledygook), I'll try to reveal how Kubernetes is actually a natural development of the good old deployment techniques.

If you already know how to run services using virtual machines, hopefully, you'll see that there's not much of a difference in the end. And if you're totally new to operating services at scale, following through the evolution of the technology might help you as well with the understanding of contemporary approaches.

As usual, this article is not meant to be comprehensive. Rather it's an attempt to summarize my personal experience and how my understanding of the domain has been forming over the years.

Read more

Kubernetes Ephemeral Containers and kubectl debug Command

Last week at KubeCon, there was a talk about Kubernetes ephemeral containers. The room was super full - some people were even standing by the doors trying to sneak in. "This must be something really great!" - thought I and decided to finally give Kubernetes ephemeral containers a try.

So, below are my findings - traditionally sprinkled with a bit of containerization theory and practice 🤓

TL;DR: Ephemeral containers are indeed great and much needed. The fastest way to get started is the kubectl debug command. However, this command might be tricky to use if you're not container-savvy.

Read more

Cracking the Docker CLI: How to Grasp Container Management Commands

When you are new to Docker (or Podman, or nerdctl, or alike), the number of commands to study might be truly overwhelming.

Docker tries to control the complexity of its CLI by employing a neat grouping technique. The first thing you see after running docker help is a list of so-called Management Commands - umbrella entry points gathering the actual commands by their area of responsibility. But even this list is no short, and it's actually a list of lists!

The list of Docker Management Commands.

Also, historically, many commands are known through their shorter but vaguer aliases - for instance, you'd rather stumble upon docker ps than docker container list in the wild. So, the struggle is real 🤪

However, there might be a way to internalize (at least some of) the most important Docker commands without the brute-force memorization!

The goal of this article is to show how a tiny bit of understanding of the containers' nature can help you master Docker's CLI, starting from the most foundational group of commands - commands to manage containers.

Read more

Learning Docker with Docker - Toying With DinD For Fun And Profit

Here is a little exercise to deepen your understanding of containers... through toying with them 🧸 The goal is to show that containers aren't just Linux processes, they are also Linux files!

The idea is simple - take a Linux machine equipped with the Docker daemon and run on it a bunch of well-known commands like docker create|start|exec|... keeping a close eye on the machine's filesystem and hoping for an interesting discovery or two.

Read more