SysVinit to Systemd Cheatsheet

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This is a document to help system administrators who need to understand what commands in systemd replace their old workflow in SysVinit.
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== Commands ==
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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]].
  
{|
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{{admon/tip | 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
!SystemVinit Command!!Systemd Command!!Notes
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systemctl replacements. }}
 +
 
 +
== Services ==
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 +
{|border="1" cellspacing="0"
 +
!Sysvinit Command!!Systemd Command!!Notes
 
|-
 
|-
| ls -al /etc/rc.d/init.d || systemctl --all || Used to list the services that can be started or stopped
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| service frobozz start || systemctl start frobozz.service || Used to start a service (not reboot persistent)
 
|-
 
|-
| chkconfig httpd --list || || Used to list what levels this service is configured on or off
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| service frobozz stop || systemctl stop frobozz.service || Used to stop a service (not reboot persistent)
 
|-
 
|-
| chkconfig httpd levels 345 on || || Turn the service on for the next reboot
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| service frobozz restart || systemctl restart frobozz.service  || Used to stop and then start a service
 
|-
 
|-
| chkconfig httpd levels 345 off || || Turn the service off for the next reboot
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| service frobozz reload || systemctl reload frobozz.service  || When supported, reloads the config file without interrupting pending operations.
 
|-
 
|-
| service httpd start || systemctl start httpd.service OR service httpd start || Used to start a service (not reboot persistent)
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| service frobozz condrestart || systemctl condrestart frobozz.service || Restarts if the service is already running.
 
|-
 
|-
| service httpd stop || systemctl stop httpd.service OR service httpd stop || Used to stop a service (not reboot persistent)
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| service frobozz status || systemctl status frobozz.service || Tells whether a service is currently running.
 
|-
 
|-
| service httpd restart || systemctl restart httpd.service OR service httpd restart || Used to stop and then start a service
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| ls /etc/rc.d/init.d/ || systemctl list-unit-files --type=service (preferred)<br />ls /lib/systemd/system/*.service /etc/systemd/system/*.service|| Used to list the services that can be started or stopped <br /> Used to list all the services and other units
 
|-
 
|-
| service httpd reload || systemctl reload httpd.unit OR service httpd reload || When supported, reloads the config file without interrupting pending operations.
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| chkconfig frobozz on || systemctl enable frobozz.service || Turn the service on, for start at next boot, or other trigger.
 
|-
 
|-
| service httpd condrestart || systemctl reload-or-restart httpd.unit OR systemctl condrestart httpd.unit OR service httpd condrestart || when supported restarts if the service is already running.
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| chkconfig frobozz off || systemctl disable frobozz.service || Turn the service off for the next reboot, or any other trigger.
 
|-
 
|-
| telinit 3 || systemctl isolate runlevel3.target OR telinit 3 || Change to multi-user run level. See also: [[#Runlevels| Runlevels]]
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| chkconfig frobozz || systemctl is-enabled frobozz.service || Used to check whether a service is configured to start or not in the current environment.
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|-
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| chkconfig --list || systemctl list-unit-files --type=service(preferred)<br/>ls /etc/systemd/system/*.wants/ || Print a table of services that lists which runlevels each is configured on or off
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|-
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| chkconfig frobozz --list || ls /etc/systemd/system/*.wants/frobozz.service || Used to list what levels this service is configured on or off
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|-
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| chkconfig frobozz --add || systemctl daemon-reload || Used when you create a new service file or modify any configuration
 
|-
 
|-
| 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.  See also: [[#Runlevels| Runlevels]]
 
 
|}
 
|}
  
== Runlevels ==
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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.
  
runlevels are used with telinit and on the kernel command line in SystemVinit.  With systemd, the following can be used instead.
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{{admon/warning|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.
  
{|
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Check the package-specific release notes for any services that may have done this.}}
!SystemVinit Runlevel!!Systemd Target!!Notes
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 +
== Runlevels/targets ==
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 +
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>).
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 +
{|border="1" cellspacing="0"
 +
!Sysvinit Runlevel!!Systemd Target!!Notes
 
|-
 
|-
| 0 || || Halt the system.
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| 0 || runlevel0.target, poweroff.target || Halt the system.
 
|-
 
|-
| 1, s, single || || Single user mode.
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| 1, s, single || runlevel1.target, rescue.target || Single user mode.
 
|-
 
|-
| 2, 4 || || User/sites may define runlevels with sets of packages for these.
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| 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.
 
| 3 || runlevel3.target, multi-user.target || Multi-user, non-graphical.  Users can usually login via multiple consoles or via the network.
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| 5 || runlevel5.target, graphical.target || Multi-user, graphical.  Usually has all the services of runlevel 3 plus a graphical login.
 
| 5 || runlevel5.target, graphical.target || Multi-user, graphical.  Usually has all the services of runlevel 3 plus a graphical login.
 
|-
 
|-
| 6 || || Reboot
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| 6 || runlevel6.target, reboot.target || Reboot
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|-
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| emergency || emergency.target || Emergency shell
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|-
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|}
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 +
Changing runlevels:
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{|border="1" cellspacing="0"
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!Sysvinit Command!!Systemd Command!!Notes
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|-
 +
| telinit 3 || systemctl isolate multi-user.target (OR systemctl isolate runlevel3.target OR telinit 3) || Change to multi-user run level.
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|-
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| 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.
 
|}
 
|}

Revision as of 03:37, 25 January 2013

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.

Idea.png
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

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/ systemctl list-unit-files --type=service (preferred)
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.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 --list systemctl list-unit-files --type=service(preferred)
ls /etc/systemd/system/*.wants/
Print a table of services that lists which runlevels each is configured on or off
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.

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.