Getting to know systemd
In this recipe, we'll explore what systemd is, how it handles the system, and all of the system's services.
Historically, Linux has been managed with several smaller pieces. For example,
init was the first process on the system, which started other processes and daemons to bring up the system. System daemons were handled by shell scripts, also called init scripts. Logging was done either by the daemon itself via files or
syslog. Networking was also handled by multiple scripts (and still is in some Linux distributions).
Nowadays, though, the entire system is handled by systemd. For example, the first process on the system is now
systemd (which we have seen in previous chapters). Daemons are handled by something called unit files, which create a unified way of controlling daemons on the system. Logging is handled by journald, systemd's logging daemon. But do note that syslog is still used by many daemons to do extra logging. Later in this...