SysVinit to Systemd Cheatsheet

SysVinit to Systemd Cheatsheet
From: https://fedoraproject.org/wiki/SysVinit_to_Systemd_Cheatsheet


Intro Services runlevels/targets Changing Runlevels


SysVinit to Systemd Cheatsheet
This page was last edited on 11 January 2017, at 10:33.

This is a document to help system administrators who need to understand what commands in systemd replace their old workflow in sysvinit. If you want general information on systemd, refer to systemd.

Note 
on 'service' and 'chkconfig' commands
The 'service' and 'chkconfig' commands will mostly continue to work as expected in the systemd world, this guide is how to use the native systemctl replacements.


Services

Note that all recent versions of systemctl assume the '.service' if left off. So, 'systemctl start frobozz.service' is the same as 'systemctl start frobozz'


 Sysvinit Command Systemd Command Notes
service frobozz start systemctl start frobozz Used to start a service (not reboot persistent)
service frobozz stop systemctl stop frobozz Used to stop a service (not reboot persistent)
service frobozz restart systemctl restart frobozz Used to stop and then start a service
service frobozz reload systemctl reload frobozz When supported, reloads the config file without interrupting pending operations.
service frobozz condrestart systemctl condrestart frobozz Restarts if the service is already running.
service frobozz status systemctl status frobozz Tells whether a service is currently running.
ls /etc/rc.d/init.d/ systemctl (or) systemctl list-unit-files --type=service (or)
 ls /lib/systemd/system/*.service /etc/systemd/system/*.service Used to list the services that can be started or stopped 
Used to list all the services and other units
chkconfig frobozz on systemctl enable frobozz Turn the service on, for start at next boot, or other trigger.
chkconfig frobozz off systemctl disable frobozz Turn the service off for the next reboot, or any other trigger.
chkconfig frobozz systemctl is-enabled frobozz Used to check whether a service is configured to start or not in the current environment.
chkconfig --list systemctl list-unit-files --type=service (or) ls /etc/systemd/system/*.wants/ Print a table of services that lists which runlevels each is configured on or off
chkconfig --list | grep 5:on systemctl list-dependencies graphical.target Print a table of services that will be started when booting into graphical mode
chkconfig frobozz --list ls /etc/systemd/system/*.wants/frobozz.service Used to list what levels this service is configured on or off
chkconfig frobozz --add systemctl daemon-reload Used when you create a new service file or modify any configuration

Note that all /sbin/service and /sbin/chkconfig lines listed above continue to work on systemd, and will be translated to native equivalents as necessary. The only exception is chkconfig --list.
	Additional commands
In SysVinit, services can define arbitrary commands. Examples would be service iptables panic, or service httpd graceful. Native systemd services do not have this ability.

Any service that defines an additional command in this way would need to define some other, service-specific, way to accomplish this task when writing a native systemd service definition.
Check the package-specific release notes for any services that may have done this.



Runlevels/targets
Systemd has a concept of targets which serve a similar purpose as runlevels but act a little different. Each target is named instead of numbered and is intended to serve a specific purpose. Some targets are implemented by inheriting all of the services of another target and adding additional services to it. There are systemd targets that mimic the common sysvinit runlevels so you can still switch targets using the familiar telinit RUNLEVEL command. The runlevels that are assigned a specific purpose on vanilla Fedora installs; 0, 1, 3, 5, and 6; have a 1:1 mapping with a specific systemd target. Unfortunately, there's no good way to do the same for the user-defined runlevels like 2 and 4. If you make use of those it is suggested that you make a new named systemd target as /etc/systemd/system/$YOURTARGET that takes one of the existing runlevels as a base (you can look at /lib/systemd/system/graphical.target as an example), make a directory /etc/systemd/system/$YOURTARGET.wants, and then symlink the additional services that you want to enable into that directory. (The service unit files that you symlink live in /lib/systemd/system).


Sysvinit Runlevel Systemd Target Notes
0 runlevel0.target, poweroff.target Halt the system.
1, s, single runlevel1.target, rescue.target Single user mode.
2, 4 runlevel2.target, runlevel4.target, multi-user.target User-defined/Site-specific runlevels. By default, identical to 3.
3 runlevel3.target, multi-user.target Multi-user, non-graphical. Users can usually login via multiple consoles or via the network.
5 runlevel5.target, graphical.target Multi-user, graphical. Usually has all the services of runlevel 3 plus a graphical login.
6 runlevel6.target, reboot.target Reboot
emergency emergency.target Emergency shell




Changing runlevels:


Sysvinit Command Systemd Command Notes
telinit 3 systemctl isolate multi-user.target (OR systemctl isolate runlevel3.target OR telinit 3) Change to multi-user run level.
sed s/^id:.*:initdefault:/id:3:initdefault:/ ln -sf /lib/systemd/system/multi-user.target /etc/systemd/system/default.target Set to use multi-user runlevel on next reboot.

Kernel Options:

The above systemd targets can be used when booting. At the GRUB menu, edit the selection to add "systemd.unit=target" (without the double-quotation marks) as a kernel option where target is one of the above. (For example, "rescue.target".)

	Tip: the ".target" extention is optional. The "systemd.unit=rescue" kernel option works the same as "systemd.unit=rescue.target".

Sysvinit Command	Systemd Command	Notes
service frobozz start	systemctl start frobozz	Used to start a service (not reboot persistent)
service frobozz stop	systemctl stop frobozz	Used to stop a service (not reboot persistent)
service frobozz restart	systemctl restart frobozz	Used to stop and then start a service
service frobozz reload	systemctl reload frobozz	When supported, reloads the config file without interrupting pending operations.
service frobozz condrestart	systemctl condrestart frobozz	Restarts if the service is already running.
service frobozz status	systemctl status frobozz	Tells whether a service is currently running.
ls /etc/rc.d/init.d/	systemctl (or) systemctl list-unit-files --type=service (or) ls /lib/systemd/system/.service /etc/systemd/system/.service	Used to list the services that can be started or stopped Used to list all the services and other units
chkconfig frobozz on	systemctl enable frobozz	Turn the service on, for start at next boot, or other trigger.
chkconfig frobozz off	systemctl disable frobozz	Turn the service off for the next reboot, or any other trigger.
chkconfig frobozz	systemctl is-enabled frobozz	Used to check whether a service is configured to start or not in the current environment.
chkconfig --list	systemctl list-unit-files --type=service (or) ls /etc/systemd/system/*.wants/	Print a table of services that lists which runlevels each is configured on or off
chkconfig --list \| grep 5:on	systemctl list-dependencies graphical.target	Print a table of services that will be started when booting into graphical mode
chkconfig frobozz --list	ls /etc/systemd/system/*.wants/frobozz.service	Used to list what levels this service is configured on or off
chkconfig frobozz --add	systemctl daemon-reload	Used when you create a new service file or modify any configuration

Sysvinit Runlevel	Systemd Target	Notes
0	runlevel0.target, poweroff.target	Halt the system.
1, s, single	runlevel1.target, rescue.target	Single user mode.
2, 4	runlevel2.target, runlevel4.target, multi-user.target	User-defined/Site-specific runlevels. By default, identical to 3.
3	runlevel3.target, multi-user.target	Multi-user, non-graphical. Users can usually login via multiple consoles or via the network.
5	runlevel5.target, graphical.target	Multi-user, graphical. Usually has all the services of runlevel 3 plus a graphical login.
6	runlevel6.target, reboot.target	Reboot
emergency	emergency.target	Emergency shell

Sysvinit Command	Systemd Command	Notes
telinit 3	systemctl isolate multi-user.target (OR systemctl isolate runlevel3.target OR telinit 3)	Change to multi-user run level.
sed s/^id:.*:initdefault:/id:3:initdefault:/	ln -sf /lib/systemd/system/multi-user.target /etc/systemd/system/default.target	Set to use multi-user runlevel on next reboot.