Page 60 - RHEL8 BOOK
P. 60
Change run levels (targets) with system
RUN LEVELS
Systemd
Systemd is a replacement to the older traditional "System V init" system. systemd stands for system
daemon. systemd was designed to allow for better handling of dependencies and have the ability to handle
more work in parallel at system startup. systemd supports snapshotting of your system and the restoring
of your systems state, keeps track of processes stored in what is known as a "cgroup" as opposed to the
conventional "PID" method. systemd is now shipping by default with many popular Linux distributions
such as Fedora, Mandriva, Mageia, Arch Linux, CentOS 7, RHEL 7.0 (Red Hat Enterprise Linux) and
Oracle Linux 7.0. systemd refers to runlevels as targets.
Init reads /etc/inittab
This file contains what programs or services should be run at different run levels:
init 0 - shutdown
init 1 - single user mode
init 2 - multiuser mode + only text + No support for NFS
init 3 - multiuser mode + only text + Full Support for all services
init 4 (unused)
init 5 multiuser mode + text mode+ GUI +Full support for all services
init 6 restart or reboot
S. Pradhan
(MCA, MBA-IT, BCA, CCNA, MCSA 2012, RHCE, ETHICAL HACKING)
Email Id:-spradhan.iiht@gmail.com
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