If you’re new to systemd, make sure that you first look here and then come back, so that you have an understanding about what I talked in this page. Below shows a quick comparison between systemd and init.
|System startup||First process (PID:1) is system, thereby initializing the system and launching all the service.Also stores initial log messages.||Init becomes parent or grandparent of all system processes after init is started. Doesn’t store initial log messages.|
|System Services Management||Systemctl command replacing traditional service and chkconfig.||Service and chkconfig commands for service start/stop and to identify run levels respectively.|
|Run level change||Introducing concept of targets, representing a group of services that are started or stopped. A target inside another target is also possible.||Runlevels to identify set of services that would start/stop when that runlevel was requested.|
|Default runlevel||Default runlevel replaced by default targets, which is linked to multi-user target by default. Location is /etc/system/system/default.target||Default runlevel set in /etc/inittab file.|
|Service location||Services in the name <service>.service and stored in /lib/systemd/system and /etc/systemd/system||Services stored as scripts in the location /etc/init.d and then linked to runlevel directories.|
|Config files||Still files in /etc/sysconfig, but services can be modified by adding files to /etc/systemd directory.||/etc/inittab file was used by the init process. Changes to the services were done in files in /etc/sysconfig directory.|