RHCSA Rapid Track

The systemd utility provides a method for activating system resources, server daemons, and other processes, both at boot time and on a running system.

Use the systemctl utility to start, stop, reload, enable, and disable services.

Use the systemd utility to manage service units, socket units, and path units.

Use the systemctl status command to determine the status of system daemons and network services that the systemd utility started.

The systemctl list-dependencies command lists all service units that a specific service unit depends on.

The systemd utility can mask a service unit so that it does not run, even to satisfy dependencies.

The systemctl reboot and systemctl poweroff commands reboot and power off a system, respectively.

The systemctl isolate target-name.target command switches to a new target at runtime.

The systemctl get-default and systemctl set-default commands can query and set the default target.

You can use the rd.break option on the kernel command line to interrupt the boot process before control is handed over from the initramfs image. The root file system is mounted read-only in the /sysroot directory.

The emergency target can diagnose and fix file-system issues.