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Revision as of 20:38, 9 September 2010 by Notting (talk | contribs) (→‎Services)

This is a document to help system administrators who need to understand what commands in systemd replace their old workflow in SysVinit.

Services

SystemVinit Command Systemd Command Notes
ls -al /etc/rc.d/init.d systemctl --all --type=service Used to list the services that can be started or stopped
chkconfig frobozz --list Used to list what levels this service is configured on or off
chkconfig frobozz --level 345 on Turn the service on for the next reboot
chkconfig frobozz --level 345 off Turn the service off for the next reboot
service frobozz start systemctl start frobozz.service OR service frobozz start Used to start a service (not reboot persistent)
service frobozz stop systemctl stop frobozz.service OR service frobozz stop Used to stop a service (not reboot persistent)
service frobozz restart systemctl restart frobozz.service OR service frobozz restart Used to stop and then start a service
service frobozz reload systemctl reload frobozz.service OR service frobozz reload When supported, reloads the config file without interrupting pending operations.
service frobozz condrestart systemctl reload-or-restart frobozz.service OR systemctl condrestart frobozz.service OR service frobozz condrestart When supported, restarts if the service is already running.
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

runlevels are used with telinit and on the kernel command line in SystemVinit. These traditional ways of switching runlevels still work with systemd, but additionally, the following can be used instead.

SystemVinit Runlevel Systemd Target Notes
0 Halt the system.
1, s, single, emergency Single user mode.
2, 4 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 Reboot

Changing runlevels:

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