Category Archives: Technical

“Rational” IT related entries.

Authentik: set custom username for OAuth application (e.g. for Apache Guacamole) via a property mapping

If you use Authentik ( as an OAuth authentication provider for your Apache Guacamole ( instance and you’d like to customize usernames for Guacamole, here’s how you can achieve this. The steps described below may work for other applications, wired … Continue reading

Posted in How to’s | Tagged , | Leave a comment

Guacamole 1.4: “Creation of WebSocket tunnel to guacd failed”

Problem: Guacamole 1.4 shows “internal error” when making any connection and in /var/log/tomcat9/catalina.out you see something like:

Posted in Solutions | Tagged | 2 Comments

Guacamole 1.4: “Log in failed” for RDP connections

Problem (Guacamole 1.4 while connecting to an RDP server): …and in logs:

Posted in Solutions | Tagged | 1 Comment

Serving acme-challenges from two web-servers sharing the same domain via nginx

Say you have nginx listening on port 80 and sharing a domain with another web-server (e.g. Proxmox web-server) that is listening on a different port, and you want to route HTTP-01 (“acme-challenge”) requests to that second web-server.

Posted in How to’s | Tagged | Leave a comment

Confluence: broken links and macros after migrating Postgres database

Problem: after migrating Atlassian Confluence PostgreSQL database to another server, you’re seeing lots of broken links (in red color) and some navigation macros not working properly (showing errors such as “page not found”). The first thing Atlassian themselves and their … Continue reading

Posted in Solutions | Tagged | Leave a comment

Zola + Vite demo

How to neatly wire up Zola (static site generator) with Vite (frontend build tool) without special plugins (a minimal demo).

Posted in How to’s | Tagged , | Leave a comment

Postgres database on a separate drive

In psql: CREATE TABLESPACE mytablespace LOCATION ‘/Volumes/MyVolume/postgres’; CREATE DATABASE mydatabase TABLESPACE mytablespace; Kudos to GregHNZ for posting this on StackOverflow.

Posted in How to’s | Tagged , | 2 Comments

Django + Vue CLI + Webpack demo

How to wire up a Vue CLI app and Webpack to Django templates with routing, hot reload, code-splitting and without any extra plugins (a minimal demo + explanation).

Posted in How to’s | Tagged , , | Leave a comment

Proxmox: QEMU Guest Agent is not running — qmp command ‘guest-ping’ failed

Hey fellow Internet dweller, are you worried about the following message appearing during backup of a suspended virtual machine in Proxmox?

Posted in Solutions | Tagged , | 3 Comments

Use macOS native color picker in VS Code (like “Insert Color” in TextMate)

A tiny extension for Visual Studio Code, written by me (GitHub).

Posted in Releases | Tagged | Leave a comment