SysVinit to Systemd Cheatsheet

From FedoraProject

(Difference between revisions)
Jump to: navigation, search
(fix capitalization)
Line 1: Line 1:
 
{{autolang|base=yes}}
 
{{autolang|base=yes}}
  
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]].
+
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 that the 'service' and 'chkconfig' commands will mostly continue to work as expected in the systemd world, this guide is how to use the native  
 
Note that the 'service' and 'chkconfig' commands will mostly continue to work as expected in the systemd world, this guide is how to use the native  
Line 9: Line 9:
  
 
{|
 
{|
!SystemVinit Command!!Systemd Command!!Notes
+
!sysvinit Command!!systemd Command!!Notes
 
|-
 
|-
 
| service frobozz start || systemctl start frobozz.service || Used to start a service (not reboot persistent)
 
| service frobozz start || systemctl start frobozz.service || Used to start a service (not reboot persistent)
Line 47: Line 47:
 
== Runlevels/targets ==
 
== 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 ''target''s that mimic the common SystemVinit runlevels so you can still switch ''target''s using the familiar <code>telinit RUNLEVEL</code> 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 <code>/etc/systemd/system/$YOURTARGET</code> that takes one of the existing runlevels as a base (you can look at <code>/lib/systemd/system/graphical.target</code> as an example), make a directory <code>/etc/systemd/system/$YOURTARGET.wants</code>, and then symlink the additional services that you want to enable into that directory.  (The service unit files that you symlink live in <code>/lib/systemd/system</code>).
+
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 ''target''s that mimic the common sysvinit runlevels so you can still switch ''target''s using the familiar <code>telinit RUNLEVEL</code> 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 <code>/etc/systemd/system/$YOURTARGET</code> that takes one of the existing runlevels as a base (you can look at <code>/lib/systemd/system/graphical.target</code> as an example), make a directory <code>/etc/systemd/system/$YOURTARGET.wants</code>, and then symlink the additional services that you want to enable into that directory.  (The service unit files that you symlink live in <code>/lib/systemd/system</code>).
  
 
{|
 
{|
!SystemVinit Runlevel!!Systemd Target!!Notes
+
!sysvinit Runlevel!!systemd Target!!Notes
 
|-
 
|-
 
| 0 || runlevel0.target, poweroff.target || Halt the system.
 
| 0 || runlevel0.target, poweroff.target || Halt the system.
Line 71: Line 71:
  
 
{|
 
{|
!SystemVinit Command!!Systemd Command!!Notes
+
!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.
 
| telinit 3 || systemctl isolate multi-user.target (OR systemctl isolate runlevel3.target OR telinit 3) || Change to multi-user run level.

Revision as of 16:47, 15 April 2011

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 that 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

sysvinit Command systemd Command Notes
service frobozz start systemctl start frobozz.service Used to start a service (not reboot persistent)
service frobozz stop systemctl stop frobozz.service Used to stop a service (not reboot persistent)
service frobozz restart systemctl restart frobozz.service Used to stop and then start a service
service frobozz reload systemctl reload frobozz.service When supported, reloads the config file without interrupting pending operations.
service frobozz condrestart systemctl condrestart frobozz.service Restarts if the service is already running.
service frobozz status systemctl status frobozz.service Tells whether a service is currently running.
ls /etc/rc.d/init.d/ ls /lib/systemd/system/*.service /etc/systemd/system/*.service Used to list the services that can be started or stopped
chkconfig frobozz on systemctl enable frobozz.service Turn the service on, for start at next boot, or other trigger.
chkconfig frobozz off systemctl disable frobozz.service Turn the service off for the next reboot, or any other trigger.
chkconfig frobozz systemctl is-enabled frobozz.service Used to check whether a service is configured to start or not in the current environment.
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 Not needed, no equivalent.

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.

Warning (medium size).png
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.