Linux Café

Introduction to systemd-resolved

I’ve always been curious about how my Linux system resolves domain names. Recently, I’ve been dealing with some DNS resolution issues at home, which led me to dig into systemd-resolved. As it turns out, many Linux distributions, including Ubuntu and Fedora, use systemd-resolved as their DNS resolver by default. In this article, I’ll share my experience with getting reliable DNS resolution at home using systemd-resolved.

Understanding systemd-resolved

systemd-resolved is part of the systemd suite and provides a DNS resolver service. It’s designed to be a caching, validating, and recursive DNS resolver - which means it can cache DNS responses, validate DNSSEC records, and perform recursive DNS lookups. To check if systemd-resolved is running on your system, you can use the following command:

Introduction to Self-Hosted Chaos

I’ve been self-hosting various services at home for a while now, and one thing that’s always been a pain point is managing SSL certificates. With multiple services running on different machines, each requiring its own certificate, it’s easy to lose track of which ones are due for renewal. I’ve seen this go wrong when a certificate expires unexpectedly, taking down a service with it. To avoid this, I’ve implemented a centralized certificate management system, which I’ll outline in this article.

Taming Terminal History Chaos

I’ve spent years working in the terminal, and my command history has grown out of control. It’s frustrating when you need to recall a specific command, but it’s buried deep in your history. I’ve seen this go wrong when trying to debug an issue or repeat a complex process. Recently, I decided to take matters into my own hands and create a custom Bash setup to organize my command line history.

Introduction to Log Noise

I’ve learned the hard way that managing log files is crucial to keeping my small home server running smoothly. Log noise, in particular, can be a real pain - it’s like trying to find a needle in a haystack. In this article, I’ll share how I use journalctl and logrotate to tame log noise and keep my system healthy.

Understanding Log Noise

Log noise refers to the overwhelming amount of log data generated by various system components. This noise makes it tough to spot critical errors or security issues. In a small home server setup, log noise can lead to disk space issues, slow down performance, and make troubleshooting a nightmare. I’ve seen this go wrong when I neglected to monitor my log files, and it wasn’t pretty.

Introduction to Taming Removable Device Chaos

I’ve lost count of how many times I’ve struggled with removable devices on Linux. Whether it’s a USB drive, an SD card, or an external hard drive, these devices can be a real hassle. But over the years, I’ve learned a thing or two about how to keep them in check using Udev rules and automount tweaks.

Understanding Udev

Udev is the device manager for Linux, and it’s what creates device nodes in the /dev directory and handles device hotplugging. The real trick is using Udev rules to customize its behavior. To get started, you’ll need to create a new file in the /etc/udev/rules.d directory. I usually start with a file like 99-removable-devices.rules, which you can create using the following command:

Introduction to Log Noise

I’ve seen this go wrong when you’re drowning in a sea of log data - it’s overwhelming, to say the least. With systemd’s journaling capabilities, logging has become more efficient and centralized, but that also means you’re dealing with a massive volume of log data. This is where people usually get burned, as it’s tough to identify real issues. That’s where journalctl comes in - a powerful command-line utility for querying and managing systemd journals.

Introduction to Rescuing Borked Linux Systems

I’ve seen this go wrong when you least expect it - a misconfigured system file, a failed update, or an accidental deletion of a critical file can leave your Linux system in a borked state. Whether you’re working on a desktop, server, or in a homelab setup, having a reliable method to rescue and restore your system is invaluable. In my experience, rsync combined with temporary snapshots is one of the most effective tools for this purpose.

Introduction to systemd Recovery

I’ve seen this go wrong when a systemd update fails - it’s a pretty stressful experience, especially when systemd is the core init system for your Linux distribution. Recently, I had a similar issue on my small home server. The update process seemed fine at first, but after a reboot, I was greeted with an error message indicating that systemd had failed to start.

Identifying the Problem

The real trick is to stay calm and use the right tools to diagnose the issue. I booted into rescue mode using a live USB stick, which gave me access to the filesystem. From there, I inspected the systemd logs using the following command:

Introduction to the Problem

I’ve been experimenting with rootless Podman containers on my Linux system, and I’m sure I’m not the only one who’s pushed the limits of what’s possible without root privileges. However, in my enthusiasm, I once accidentally removed the initramfs image, which led to a failed boot. Don’t bother with trying to guess how I did it - let’s just say it was a misconfiguration that allowed a rootless container to access the host’s filesystem. This article will guide you through recovering from such a situation, focusing on practical steps and commands to get your system back up and running.

Introduction to Background Tasks

I’ve been in situations where running a command or process in the background is a must - think long-running backups, downloads, or compilations. In those cases, being able to continue working on other tasks is a huge plus. Here, we’ll explore three ways to manage background tasks: nohup, disown, and systemd’s linger option. Each has its own use cases, and I’ll share some practical tips on when to use each.