These notes have been tested with Proxmox Virtual Environment (PVE) 8.2.4, Debian 12 and cloud-init 22.4.2 (from Debian 12 packaging). First create a virtual machine and install Debian Linux on it normally, with all the additional tools and updates as required. I usually use the netinstall CD image from Debian. After completing the installation, for […]
Category: System administration
Size of Debian Linux Installation
I often need a Linux virtual machine for testing specific things. Debian Linux is my choice of Linux distribution, and I have wondered how much space does each installed package take in it, to possibly optimize the size of the VM if needed. I installed two VMs: The results after “sudo apt clean“: Installation Disk […]
VDR Setup, 2025 Edition
SQLite Commands
You know cloud computing is powered by shell scripts and SQLite databases, right? That’s how the saying goes. But what is an SQLite database anyway? It is a file, and it can be inspected with the SQLite application or a compatible library. There is no server daemon to connect to. Usually, when accessing a database, […]
24-hour Timestamps for Zabbix 7
The default language in the Zabbix user interface (UI) installation is “en_US”, meaning English (US). Probably because of the European roots of Zabbix, the timestamps have still been shown in 24-hour (world-standard) format, up until Zabbix version 6.4. Now in Zabbix 7.0 the default time display format has been changed to correspond to the selected […]
PostgreSQL Upgrades on Debian Linux
When doing a major version upgrade on Debian Linux with PostgreSQL server installed (using Debian-provided packages), this always catches me: After the upgrade there will be two different PostgreSQL instances running, it won’t do an in-place upgrade for the database automatically. In order to get the existing database running on the newer PostgreSQL version, this […]
Commanding Devices with Tmux
Let’s go right away to the question: How do I enter commands on two devices at the same time? One of the possible answers is: With tmux. My usual workflow to connect to the end devices is from a Linux host that has tmux installed. The situation can look for example like this: Before being […]
Manpages for systemd
Because I seem to frequently search for these manpages: systemd versions in Debian Linux:
Configuring Hourly Log Rotation with Logrotate and Rsyslog
Logrotate runs daily by default on Debian Linux. It is scheduled to run at 00:00:00 with systemd: markku@logtest:~$ systemctl list-timers NEXT LEFT LAST PASSED UNIT ACTIVATES Mon 2023-11-20 00:00:00 EET 2h 20min left Sun 2023-11-19 00:00:17 EET 21h ago logrotate.timer logrotate.service … When you want logrotate to rotate files hourly, you need two changes: For […]
Tools for Debian Packages
Debian has been my primary Linux distribution of choice since 2003. That’s twenty years! How time flies! I haven’t ever worked as full-time server administrator but running and operating various kinds of systems have always been part of my skills, and it has made it possible for me to leverage wide range of tooling required […]