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This is the place where I publish articles about my findings and progress in the awesome world of technology and beyond! Also, check out my projects or get in touch.
My latest articles //
Kubernetes cluster introspection – the 5 best tools to better understand your cluster
Cluster introspection tools help you better understand what is going on in your Kubernetes cluster, by presenting the workloads visually. In this article I present a taxonomy of available tools and briefly present the tools Lens, k9s, kubenav, Octant, Headlamp, Kubernetes dashboard, Skooner and Portainer. I conclude by giving general recommendations. Introduction A very common task for developers, operations and…
Local Kubernetes development clusters: the 5 best local cluster compared
If you develop software that runs on Kubernetes, a local development cluster can significantly speed up your development iteration speed, because everything happens locally. I discuss the pros and cons of local clusters and then present the tools Docker for Desktop, Rancher Desktop, kind, k3d and Minikube, and how they compare. I finish with details regarding how to get locally-built…
Speed up GitLab CI – the 5 best tips for fast pipelines
Starting from an overview of frequent causes for slow pipelines, I derive 5 tips to speed up GitLab CI pipelines. These include choosing the appropriate runner infrastructure, choosing the right caching approach (Docker vs. GitLab), DAG pipelines, mixing GitLab’s caches and artifacts, and optimizing individual jobs (e.g. via parallelization). Introduction As I already explained in the CI/CD Basics article, the…
GitLab CI/CD: GitLab vs. Docker caching – how to get insanely fast CI/CD pipelines
Using a Node.js example project I demonstrate how Docker-based caching can speed up your GitLab CI/CD pipelines even more than GitLab’s built-in caching mechanism. I explain how each approach works, and what the technical prerequisites are. I also list tools that support you with setting up a Docker-based CI pipeline. Introduction Caching of files between CI jobs is a very…
Docker image tagging: best practices in a CI pipeline
This article explains why you should not tag your own Docker images with only the “latest” tag. I discuss alternative best practices, categorizing them into stable vs. unstable version tags. I also fully deconstruct a Docker image tag into its basic components to improve your understanding of Docker image names and tags. Introduction When you build a Docker image in…
Operating a self-hosted GitLab runner with Docker
In this article I explain how (and why) you install and use a Linux-based self-hosted GitLab CI/CD runner that executes jobs of your GitLab pipelines. I go into a few caveats and how you can reduce maintenance efforts for the runner to a minimum. Introduction GitLab CI/CD has a distributed architecture that consists of a GitLab server and one or…
Book recommendation: Clean Code (Robert C. Martin)
In this book recommendation, I review the book Clean Code by Robert C. Martin, released in 2008. I offer my 13 page summary of the book as free download, and provide links to further reading material. Introduction to clean code In 2008, Robert C. Martin (a.k.a. “Uncle Bob”) released the book Clean code. It was not the first book about…
Automatic Continuous Deployment of Docker containers
This article explains how to achieve Continuous Deployment of Docker-based software, using either pull-based approaches (external tools such as watchtower and harbormaster), or push-based techniques (deployment from the CI/CD pipeline). I explain the advantages and disadvantages of each approach, and also illustrate how automated testing greatly reduces the risk of unnoticed failed deployments. Introduction When you use Docker (not Kubernetes)…
Tips for operating Docker – the best tools and commands
This article presents useful tips for operating Docker engine on a Linux server. I explain how you can improve the server’s security via automatic updates and scanning the images of your running containers, how to reduce the maintenance efforts by making sure your disks don’t run out of space, and how to set up a Prometheus-based monitoring system that lets…
Docker optimization guide: the 12 best tips to optimize Docker image security
This article introduces 12 tips to optimize your Docker image security. For each tip, it explains the underlying attack vector, and one or more mitigation approaches. Tips include avoiding leaking of build secrets, running as non-root user, or how to make sure to use the most recent dependencies and updates. Introduction When you are new to Docker, you will most…