Introduction to logging

By default, Linux logs almost everything. This is important for developing a root cause analysis when things go wrong. When you're faced with a problem on a production server, all you should need to do is determine the time in which the problem started and then read the log files for the types of things that happened on the system during that time. Linux logging is very informative.

But nowadays, the way that Linux handles logging is changing. With the rise of systemd, which is now the default init system on most Linux distributions, it's taken over almost everything, including logging. In the past, you would venture into /var/log whenever you wanted to read your logs, which is a directory containing various log files in plain text format. On both Debian and CentOS, you can still find logs in /var/log, so you'll still be able to utilize them for troubleshooting the same as we always have. But it's not yet certain how much longer this will be kept around.

Many might...