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 […]
Category: System administration
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 […]
Using Tmux
A long time ago I discovered screen. It made it possible to start applications in Linux and then disconnecting the SSH session, without stopping the applications. It was magic: otherwise the the applications just terminated if the SSH connection was lost. Then I heard about tmux. It was like screen on steroids! I could split […]
Configuring MariaDB Replication
This is a plain list of actions I did when creating a MariaDB database master-slave replication setup. It is assumed that you already know why you want to create such a configuration and how you can use it in your case. Some links anyway: Global Transaction ID (mariadb.com): “[…] it is generally recommended to use […]
NetBox Database Backup
A short memo how to backup any PostgreSQL database: In .pgpass (you should keep this file protected): netbox-db-backup.sh: That will also find and delete backup files older than MAXDAYS.
PuTTY Settings in 2019 – Now in Multicolor!
I’ve “always” used PuTTY as my SSH client on Windows. And now, in 2019, I realized that there really are some settings in PuTTY that can make a difference! Here is my earlier normal view: Bash prompt and the colors looked like this: Not very modern, right? After some adjustments, here they are now: For […]
Oneshot Service in Linux Systemd
My trusty old VDR box started behaving erratically: sometimes the IR remote didn’t do anything. Rebooting the whole box usually helped, but not always. Eventually I was able to narrow the problem down: for some reason the LIRC serial driver did not correctly detect the IR receiver in the serial port at the boot. I […]