/techblog

In some rare cases you might want to run Java code as a script. Let’s discover how to create portable, executable, robust, no-compilation-needed scripts with Java 21!

Git is an important part of my daily life. Professional as well as in private I use it to manage documents and all kinds of files and changes and synchronize these between my environments.

Working alone in my repositories I can commit my changes to the branch master all day long. This works well since I am the only one working in it.

In a customer environment this is different. Different workflow might be implemented, which then require branching, merge/pull ... [continue reading]

Helidon 4 is a micro-service framework which purports to make our lives slightly better with speed of development coupled with speed of runtime while being light on the mind. Is it any good?

This guide can be used set up a vanilla/lightweight dual-stack Kubernetes (k3s) configuration on a Raspberry Pi. You can add more k3s-nodes to achieve high-availability if needed. In the end a IPv4/IPv6 Nextcloud instance ... [continue reading]

As a dedicated advocate of IPv6, I recently embarked on the task of converting my personal Kubernetes cluster to an IPv6-only environment.

Why?

The growing scarcity of IPv4 addresses is a well-known issue. ... [continue reading]

In a recent project we have successfully replaced some of our usage of ActiveMQ queues with instances of Jobrunr. Lets take a look at what Jobrunr is and why it is attractive.

Using asynchronous processing is a common theme in distributed systems - maybe the client doesn’t need to know whether something was a success or some resource intensive processing takes a while to ... [continue reading]

Jinja is a powerful template engine for Python. Inside Ansible it is often used to dynamically create files from templates and fill in placeholders with data.

The Jinja language (now in version 2) also offers features like loops and data manipulation. Building files from loops and data-structures is more complex, especially when considering whitespace and line breaks. It can get tricky very fast.

The general approach (and I think many will agree with me on this one) ... [continue reading]

Web applications may send a special HTTP method OPTIONS to query an API for functionality. If supported, the answer is a bunch of clear text HTTP headers. An OPTIONS request is usually quite lightweight for the server, but it still uses resources like connections and CPU time. The answer to an OPTIONS request seldom changes unless the API itself changes. So we have small HTTP text objects that seldom are updated. Sounds ideal for caching with Varnish.

Varnish is the ... [continue reading]

I recently migrated my Home Assistant from SQLite to PostgreSQL and found that the top Google hits gave me broken instructions. Installation and configuration of a PostgreSQL server is outside the scope of this post. I will assume that it’s acceptable with some hours without recording statistics. While I believe it should be possible to do a “hot” migration without data loss, this is outside the scope of this post. I assume you have some knowledge of shell commands and ... [continue reading]

In this guide we’ll setup and configure Jitsi together with JWT authentication, and moderated meetings to be able to host video conferences for several hundreds (thousands depending on your server) of users, with the capability to host webinars.

The last couple of years has been very productive in the open source area. More and more companies decided to go open-source, and with that many great new open-sourced (and free) options are available for both your company and private life day-to-day. ... [continue reading]