DevOps on ma.ttias.be

Linux debugging tools I use daily

mattias@ma.ttias.be (Mattias Geniar) — Fri, 12 Jun 2026 00:00:00 +0000

Every server I run, including the fleet behind Oh Dear ’s uptime checks, has the same set of debugging tools installed before anything goes wrong. Not because the application needs them, but because the one time you reach for strace is at 2am, the box is misbehaving, and apt install is the last thing you want to be doing while you work out what broke.

Transcribing my old podcast locally with open-source AI

mattias@ma.ttias.be (Mattias Geniar) — Tue, 09 Jun 2026 00:00:00 +0000

Back in 2016 and 2017 I recorded a podcast called Syscast : interviews with people I admired in the Linux, open source and infrastructure world. Matt Holt about Caddy , Daniel Stenberg about curl , Seth Vargo about Vault , and a handful more. Ten episodes, roughly ten hours of audio, and then life got in the way and I put it on pause.

Recap: measuring linux performance - how to avoid typical mistakes

mattias@ma.ttias.be (Mattias Geniar) — Thu, 09 Jul 2020 06:50:00 +0100

In the last two weeks, Peter Zaitsev published a 4-part series on measuring Linux performance on this blog.

How to measure Linux Performance Avoiding Most Typical Mistakes: Network

mattias@ma.ttias.be (Mattias Geniar) — Wed, 08 Jul 2020 06:50:00 +0100

In this series, we are talking about Linux performance measurement, how to measure it right. Linux performance is a very broad topic, so we’ll focus on the four primary resources which are typically going to drive your system performance – obviously CPU, memory, disk storage, and network.

How to measure Linux Performance Avoiding Most Typical Mistakes: Memory

mattias@ma.ttias.be (Mattias Geniar) — Mon, 06 Jul 2020 06:50:00 +0100

How to measure Linux Performance Avoiding Most Typical Mistakes: Disk Storage

mattias@ma.ttias.be (Mattias Geniar) — Thu, 02 Jul 2020 06:50:00 +0100

Adding SWAP to Linux

mattias@ma.ttias.be (Mattias Geniar) — Tue, 30 Jun 2020 00:00:00 +0000

Here are the steps needed to add a new SWAP partition to your Linux machine. This’ll allocate 2GB of space on your disk, and allow it to be used as RAM if your server is running low.

Git commit without the pre-commit hook

mattias@ma.ttias.be (Mattias Geniar) — Mon, 29 Jun 2020 00:00:00 +0000

Quick tip if you want to skip the pre-commit validations and quickly want to get a commit out there.

How to measure Linux Performance Avoiding Most Typical Mistakes: CPU

mattias@ma.ttias.be (Mattias Geniar) — Mon, 29 Jun 2020 00:00:00 +0000

In this series, we are going to talk about Linux performance measurement, how to measure it right. Linux performance is a very broad topic, so we’ll focus on the four primary resources which are typically going to drive your system performance – obviously CPU, memory, disk storage, and network.

Making life easier with cron

mattias@ma.ttias.be (Mattias Geniar) — Thu, 04 Jun 2020 00:00:00 +0000

This post shares some ideas about working with cronjobs, to help make common tasks more easy for both junior and senior sysadmins.

MySQL: ERROR 1153 (08S01): Got a packet bigger than 'max_allowed_packet' bytes

mattias@ma.ttias.be (Mattias Geniar) — Fri, 15 May 2020 00:00:00 +0000

I ran into this error when doing a very large MySQL import from a dumpfile.

Bash script to send a push notification when string is found in logs

mattias@ma.ttias.be (Mattias Geniar) — Sun, 03 May 2020 00:00:00 +0000

I had a use case where I wanted to be notified whenever a particular string occured in a log file. This seemed a bit overkill to make a custom implementation in a monitoring solution, so I wrote a simple Bash script to send me a push notification whenever it occurs.

Build & test your Laravel project via Bitbucket Pipelines

mattias@ma.ttias.be (Mattias Geniar) — Wed, 29 Apr 2020 00:00:00 +0000

This post will show you how to use Bitbucket Pipelines to build and test your Laravel Project in a docker container.

Deploying a highly-available K3s with K3sup

mattias@ma.ttias.be (Mattias Geniar) — Mon, 27 Apr 2020 00:00:00 +0000

Introduction#

Some of members of the cloud-native computing world have recently been trying to find a way to address the areas where Kubernetes falls short when trying to run on resource constrained environments.

Clean up Linux Server Using These Simple Tips

mattias@ma.ttias.be (Mattias Geniar) — Sun, 26 Apr 2020 00:00:00 +0000

Deploying a Linux server is really easy these days thanks to the abundance of cloud server providers like Linode, Digital Ocean etc. This enables not-so-expert people, like me, to deploy and manage their own Linux servers.

Different ways of writing crontab syntax

mattias@ma.ttias.be (Mattias Geniar) — Sun, 26 Apr 2020 00:00:00 +0000

Here’s what I’ve been doing for most of my life, when it comes to writing crontab entries:

Set up a custom 404 page for static sites with Caddy 2

mattias@ma.ttias.be (Mattias Geniar) — Sun, 26 Apr 2020 00:00:00 +0000

Here’s a quick example of setting up a custom 404 landing page if you use Caddy V2 to serve static sites, like this blog.

How to run HTTP/3 with Caddy 2

mattias@ma.ttias.be (Mattias Geniar) — Fri, 10 Apr 2020 06:30:00 +0100

I just migrated this webserver to Caddy 2 and with it, enabled HTTP/3 support. This post will give a short explanation how you can do that.

Migrating to Caddy 2

mattias@ma.ttias.be (Mattias Geniar) — Fri, 10 Apr 2020 06:00:00 +0100

Last week, the first Release Candidate of Caddy 2 saw the light of day. I don’t usually like to run production environments on beta software, but for Caddy I wanted to make an exception

Dumping specific tables in MySQL using mysqldump

mattias@ma.ttias.be (Mattias Geniar) — Fri, 17 Jan 2020 00:00:00 +0000

Here’s a small little trick when using mysqldump: you don’t have to dump an entire database, you can dump individual tables too.

Auto-restart a crashed service in systemd

mattias@ma.ttias.be (Mattias Geniar) — Mon, 13 Jan 2020 00:00:00 +0000

Systemd allows you to configure a service so that it automatically restarts in case it’s crashed.

Name your Laravel Horizon workers for easier debugging at the CLI

mattias@ma.ttias.be (Mattias Geniar) — Thu, 19 Dec 2019 00:00:00 +0000

As part of our Oh Dear! monitoring service , we run workers. A lot of workers. Every site uptime check is a new worker, every broken links job is a new worker, every certificate check is a- you get the idea.

Set up a static IP address on Ubuntu 18.04 LTS server

mattias@ma.ttias.be (Mattias Geniar) — Thu, 05 Dec 2019 00:00:00 +0000

If you’re setting up an Ubuntu 18.04 LTS server, you might want to give it a static IP address instead of one assigned by your router over DHCP.

Auto-start VirtualBox VMs (headless) after reboot on Mac OSX

mattias@ma.ttias.be (Mattias Geniar) — Wed, 27 Nov 2019 00:00:00 +0000

I’ve got a Mac Mini at home to act as a server & desktop. On it there are several Virtual Box VMs, among which a a pihole to block unwanted requests via DNS . It’s pretty vital these run at all time.

VirtualBox: Failed to open/create the internal network 'HostInterfaceNetworking-en0' (VERR_SUPDRV_COMPONENT_NOT_FOUND)

mattias@ma.ttias.be (Mattias Geniar) — Wed, 27 Nov 2019 00:00:00 +0000

There’s an annoying little bug in VirtualBox that can cause your network config in the VM to become invalid after a reboot of your host Mac.