Difference between revisions of "Systemd"

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m (→‎Hibernation: Fixed typos.)
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=== Hibernation ===
=== Hibernation ===
{{Merge|pm-utils|uswsusp-git is just one of the backend that pm-utils supports. Other backend also work.}}
{{Merge|pm-utils|uswsusp-git is just one of the back-ends that pm-utils supports. Other back-ends also work.}}
To hibernate your system a.k.a ''Suspend To Disk'' with {{ic|sytemctl hibernate}}, First install [https://aur.archlinux.org/packages.php?ID=44473/ uswsusp-git] from [https://wiki.archlinux.org/index.php/AUR/ AUR] and configure according to the instructions mentioned [[Uswsusp|here]]. Now do :
To hibernate your system a.k.a ''Suspend To Disk'' with {{ic|sytemctl hibernate}}, first install [https://aur.archlinux.org/packages.php?ID=44473/ uswsusp-git] from [https://wiki.archlinux.org/index.php/AUR/ AUR] and configure according to the instructions mentioned [[Uswsusp|here]]. Now do:
  # cp /usr/lib/systemd/system/systemd-hibernate.service /etc/systemd/system/
  # cp /usr/lib/systemd/system/systemd-hibernate.service /etc/systemd/system/
  # cd /etc/systemd/system/
  # cd /etc/systemd/system/
Open {{ic|systemd-hibernate.service}} with your prefered text editor  
Open {{ic|systemd-hibernate.service}} with your preferred text editor  
  # vim systemd-hibernate.service
  # vim systemd-hibernate.service
and edit the line from this :
and edit the line from this:
Line 237: Line 237:
ExecStart=/usr/lib/systemd/systemd-sleep hibernate
ExecStart=/usr/lib/systemd/systemd-sleep hibernate
to this :
to this:
Line 243: Line 243:
After that execute {{ic|systemctl hibernate}} to hibernate your system.
After that, execute {{ic|systemctl hibernate}} to hibernate your system.
=== Unit ===
=== Unit ===

Revision as of 07:01, 13 October 2012

zh-CN:Systemd Template:Article summary start Template:Article summary text Template:Article summary heading Template:Article summary wiki Template:Article summary wiki Template:Article summary wiki - systemd and udev have been merged upstream. Template:Article summary end From the project web page:

"systemd is a system and service manager for Linux, compatible with SysV and LSB init scripts. systemd provides aggressive parallelization capabilities, uses socket and D-Bus activation for starting services, offers on-demand starting of daemons, keeps track of processes using Linux control groups, supports snapshotting and restoring of the system state, maintains mount and automount points and implements an elaborate transactional dependency-based service control logic. It can work as a drop-in replacement for sysvinit."

Note: For a detailed explanation as to why Arch is switching to systemd, see: this forum post.

See also the Wikipedia article.


Things to consider before you switch

  • It is highly recommended to switch to the new initscripts configuration system described in the rc.conf article. Once you have this configuration established, you will have done most of the work needed to make the switch to systemd.
  • Do some reading about systemd.
  • Note the fact that systemd has a journal system that replaces syslog, although the two can co-exist. See the section on the journal below.
  • While systemd can replace some of the functionality of cron, acpid, or xinetd, there is no need to switch away from using the traditional daemons unless you want to.


systemd can be installed side-by-side with the regular Arch Linux initscripts package, and they can be toggled by adding/removing the init=/usr/lib/systemd/systemd kernel parameter.

A mixed systemd/sysvinit/initscripts installation

It is possible to keep systemd and sysvinit both installed and using the same configuration files so you can move back and forth between them freely:

  1. Move away from the deprecated initscripts configuration formats (there should be warnings at boot) to the native systemd configuration files, and reboot to verify that this works as expected with initscripts.
  2. Install systemd from the official repositories.
  3. Add init=/usr/lib/systemd/systemd to the kernel parameters in your bootloader.
  4. Reboot.

Systemd will start the daemons listed in /etc/rc.conf and run /etc/rc.local and /etc/rc.local.shutdown on boot/shutdown respectively. If the legacy support for DAEMONS in rc.conf or the scripts in rc.local is not needed, the corresponding service files can be masked to disable them.

Warning: In case you have daemons in the DAEMONS array which have native systemd service files, the native service files will be used automatically. However, if the names of the rc script and the systemd service file do not match, this will not work and you should make sure that only one of the two (preferably the native one) is enabled.
Warning: Systemd is an asynchronous starting process, compared to the sequential DAEMONS startup. In particular "network" being a legacy service, may start too late to enable interfaces which are required by other services. You are advised to move to netcfg or NetworkManager before embarking to systemd.

A mixed systemd/initscripts installation

It is possible to replace sysvinit with systemd, but keep initscripts around in case there are some rc scripts which do not yet have systemd equivalents.

  1. Follow the instructions for a mixed systemd/sysvinit/initscripts installation
  2. Enable daemons formerly listed in /etc/rc.conf with systemctl enable daemonname.service . For a translation of the daemons from /etc/rc.conf to systemd services, see: List of Daemons and Services. Daemons that do not yet have equivalent systemd service files should be kept in the DAEMONS array so systemd will start the legacy rc scripts.
  3. Install systemd-sysvcompat. This conflicts with sysvinit, and will prompt you to remove it.
  4. Remove the init=... entry as /sbin/init is now a symlink to systemd.
  5. Reboot.

The only difference between this and the keeping sysvinit around is that all the sysvinit binaries are replaced by symlinks to systemctl. However, the functionality should be unchanged.

A pure systemd installation

Lastly, it is possible to remove initscripts and sysvinit entirely and only use systemd.

  1. Follow the instructions for a mixed systemd/initscripts installation
  2. Make sure there are no longer any daemons being started by the DAEMONS array in /etc/rc.conf and that /etc/rc.local and /etc/rc.local.shutdown are both empty.
  3. Remove the initscripts package from your system.

Supplementary information

Tip: If you have quiet in your kernel parameters, you might want to remove it for your first couple of systemd boots, to assist with identifying any issues during boot.
Tip: If you intend to use a static IP address in a pure systemd environment without netcfg or NetworkManager, take care not to use the -s option with pacman when removing initscripts, as it will also remove the iproute2 package if it is not a dependency of another installed package. iproute2 must remain installed.

Native systemd configuration files

Note: You may need to create these files.

systemd will use /etc/rc.conf if these files are absent. Note this is temporary and not a long-term solution. It is strongly advised to use the systemd configuration files on any system.



Console and keymap

The /etc/vconsole.conf file configures the virtual console, i.e. keyboard mapping and console font.


For more info see Console fonts and Keymap.

Tip: To use the kernel compiled-in font and keymap rather than the systemd-default ones with systemd 193 or older, use:


Read man locale.conf for more options:


For more info see Locale.

Time zone

Read man 5 localtime for more options.

# ln -sf /usr/share/zoneinfo/America/Chicago /etc/localtime
Note: /etc/timezone has been deprecated in systemd-190 and can/should be deleted.

Hardware clock time

Systemd will use UTC for the hardware clock by default and this is recommended. Dealing with daylight saving time is messy. If the DST changes when your computer is off, your clock will be wrong on next boot (there is a lot more to it). Recent kernels set the system time from the RTC directly on boot without using hwclock, the kernel will always assume that the RTC is in UTC. This means that if the RTC is in local time, then the system time will first be set up wrongly and then corrected shortly afterwards on every boot. This is possibly the reason for certain weird bugs (time going backwards is rarely a good thing).

The reason for allowing the RTC to be in local time is to allow dual boot with Windows (which uses localtime). Windows is able to deal with the RTC being in UTC with a simple registry fix. If you run into issues on dual boot with Windows, you can set the hardware clock to local time.

0.0 0.0 0.0

The other parameters are still needed but are ignored by systemd.

It is generally advised to have a Network Time Protocol daemon running to keep the hardware clock synchronized with the system time.

Kernel modules loaded during boot

systemd uses /etc/modules-load.d/ to configure kernel modules to load during boot in a static list. Each configuration file is named in the style of /etc/modules-load.d/<program>.conf. The configuration files should simply contain a list of kernel module names to load, separated by newlines. Empty lines and lines whose first non-whitespace character is # or ; are ignored. Example:

# Load virtio-net.ko at boot

See also Modprobe#Options.

Kernel modules blacklist

Module blacklisting works the same way as with initscripts since it is actually handled by kmod. See Module Blacklisting for details.

Temporary files

Systemd-tmpfiles uses the configuration files in /usr/lib/tmpfiles.d/ and /etc/tmpfiles.d/ to describe the creation, cleaning and removal of volatile and temporary files and directories which usually reside in directories such as /run or /tmp. Each configuration file is named in the style of /etc/tmpfiles.d/<program>.conf. This will also override any files in /usr/lib/tmpfiles.d/ with the same name.

tmpfiles are usually provided together with service files to create directories which are expected to exist by certain daemons. For example the Samba daemon expects the directory /var/run/samba to exist and to have the correct permissions. The corresponding tmpfile looks like this:

D /var/run/samba 0755 root root

However, tmpfiles may also be used to write values into certain files on boot. For example, if you use /etc/rc.local to disable wakeup from USB devices with echo USBE > /proc/acpi/wakeup, you may use the following tmpfile instead:

w /proc/acpi/wakeup - - - - USBE

The tmpfiles method is recommended in this case since systemd doesn't actually support /etc/rc.local.

See man tmpfiles.d for details.

Remote filesystem mounts

Systemd automatically makes sure that remote filesystem mounts like NFS or Samba are only started after the network has been set up. Therefore remote filesystem mounts specified in /etc/fstab should work out of the box.

You may however want to use Automount for remote filesystem mounts to mount them only upon access. Furthermore you can use the x-systemd.device-timeout=# option in /etc/fstab to specify a timeout in case the network resource is not available.

See man systemd.mount for details.

ACPI Power Management with systemd

Systemd handles some power-related ACPI events. This is configured via the following options in /etc/systemd/logind.conf:

  • HandlePowerKey: specifies which action is invoked when the power key is pressed.
  • HandleSuspendKey: specifies which action is invoked when the suspend key is pressed.
  • HandleHibernateKey: specifies which action is invoked when the hibernate key is pressed.
  • HandleLidSwitch: specifies which action is invoked when the lid is closed.

The specified action can be one of ignore, poweroff, reboot, halt, suspend, hibernate or kexec.

If these options are not configured, systemd will use its defaults: HandlePowerKey=poweroff, HandleSuspendKey=suspend, HandleHibernateKey=hibernate, and HandleLidSwitch=suspend.

On systems which run no graphical setup or only a simple window manager like i3 or awesome, this may replace the acpid daemon which is usually used to react to these ACPI events.

In the current version of systemd, the Handle options will apply throughout the system unless they are "inhibited" (temporarily turned off) by a program, such as a power manager inside a desktop environment. If these inhibits are not taken, you can end up with a situation where systemd suspends your system, then when it wakes up the other power manager suspends it again.

Note: Currently, the power manager in newest version of KDE is the only one that issues the necessary "inhibited" commands. Until the others do, you will need to set the Handle options to ignore if you want your ACPI events to be handled by GNOME, Xfce, acpid or other programs. New versions are on the way that will include this functionality.

Sleep hooks

Systemd does not use pm-utils to put the machine to sleep when using systemctl suspend or systemctl hibernate, therefore pm-utils hooks including any custom hooks created will not be run. However, systemd provides a similar mechanism to run custom scripts on these events. Systemd runs all executables in /usr/lib/systemd/system-sleep/ and passes two arguments to each of them:

  • Argument 1: either pre or post, depending on whether the machine is going to sleep or waking up
  • Argument 2: either suspend or hibernate, depending on what has been invoked

In contrast to pm-utils, systemd will run these scripts concurrently and not one after another.

The output of your script will be logged by systemd-suspend.service or systemd-hibernate.service so you can see its output in the journal.

Note that you can also use sleep.target, suspend.target or hibernate.target to hook units into the sleep state logic instead of using scripts.

See man systemd.special and man systemd-sleep for more information.



case "$1" in
  pre )
    echo going to $2 ...
  post )
    echo waking up from $2 ...


Merge-arrows-2.pngThis article or section is a candidate for merging with pm-utils.Merge-arrows-2.png

Notes: uswsusp-git is just one of the back-ends that pm-utils supports. Other back-ends also work. (Discuss in Talk:Systemd#)

To hibernate your system a.k.a Suspend To Disk with sytemctl hibernate, first install uswsusp-git from AUR and configure according to the instructions mentioned here. Now do:

# cp /usr/lib/systemd/system/systemd-hibernate.service /etc/systemd/system/
# cd /etc/systemd/system/

Open systemd-hibernate.service with your preferred text editor

# vim systemd-hibernate.service

and edit the line from this:

ExecStart=/usr/lib/systemd/systemd-sleep hibernate

to this:


After that, execute systemctl hibernate to hibernate your system.


A unit configuration file encodes information about a service, a socket, a device, a mount point, an automount point, a swap file or partition, a start-up target, a file system path or a timer controlled and supervised by systemd. The syntax is inspired by XDG Desktop Entry Specification .desktop files, which are in turn inspired by Microsoft Windows .ini files. See man systemd.unit for more info.

Systemd commands

  • systemctl: used to introspect and control the state of the systemd system and service manager.
  • systemd-cgls: recursively shows the contents of the selected Linux control group hierarchy in a tree
  • systemadm: a graphical frontend for the systemd system and service manager that allows introspection and control of systemd (available via the systemd-ui-gitAUR package from the AUR).

View the man pages for more details.

Tip: You can use all of the following systemctl commands with the -H <user>@<host> switch to control a systemd instance on a remote machine. This will use SSH to connect to the remote systemd instance.

Analyzing the system state

List running units:

$ systemctl


$ systemctl list-units

List failed units:

$ systemctl --failed

The available unit files can be seen in /usr/lib/systemd/system/ and /etc/systemd/system/ (the latter takes precedence). You can see list installed unit files by:

$ systemctl list-unit-files

Using Units

Units can be, for example, services (.service), mount points (.mount), devices (.device) or sockets (.socket).

When using systemctl, you generally have to specify the complete name of the unit file, including its suffix, for example sshd.socket. There are however a few shortforms when specifying the unit in the following systemctl commands:

  • If you don't specify the suffix, systemctl will assume .service. For example, netcfg and netcfg.service are treated equivalent.
  • Mount points will automatically be translated into the appropriate .mount unit. For example, specifying /home is equivalent to home.mount.
  • Similiar to mount points, devices are automatically translated into the appropriate .device unit, therefore specifying /dev/sda2 is equivalent to dev-sda2.device.

See man systemd.unit for details.

Activate a unit immediately:

# systemctl start <unit>

Deactivate a unit immediately:

# systemctl stop <unit>

Restart a unit:

# systemctl restart <unit>

Ask a unit to reload its configuration:

# systemctl reload <unit>

Show the status of a unit, including whether it is running or not:

$ systemctl status <unit>

Check whether a unit is already enabled or not:

$ systemctl is-enabled <unit>

Enable a unit to be started on bootup:

# systemctl enable <unit>
Note: If services do not have an Install section, it usually means they are called automatically by other services. But if you need to install them manually, use the following command, replacing foo with the name of the service.
# ln -s /usr/lib/systemd/system/foo.service /etc/systemd/system/graphical.target.wants/

Disable a unit to not start during bootup:

# systemctl disable <unit>

Show the manual page associated with a unit (this has to be supported by the unit file):

$ systemctl help <unit>

Power Management

If you are in a local systemd-logind or ConsoleKit user session and no other session is active, the following commands will work without root privileges. If not (for example, because another user is logged into a tty), systemd will automatically ask you for the root password (see also Replacing ConsoleKit with systemd-logind).

Shut down and reboot the system:

$ systemctl reboot

Shut down and power-off the system:

$ systemctl poweroff

Shut down and halt the system:

$ systemctl halt

Suspend the system:

$ systemctl suspend

Hibernate the system:

$ systemctl hibernate


Runlevels is a legacy concept in systemd. Systemd uses 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 with the possibility of having multiple ones active at the same time. 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 SystemVinit runlevels so you can still switch targets using the familiar telinit RUNLEVEL command.

Get current runlevel/targets

The following should be used under systemd instead of runlevel:

# systemctl list-units --type=target

Create custom target

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 is 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/<your target> that takes one of the existing runlevels as a base (you can look at /usr/lib/systemd/system/graphical.target as an example), make a directory /etc/systemd/system/<your target>.wants, and then symlink the additional services from /usr/lib/systemd/system/ that you wish to enable.

Targets table

SysV 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

Change current runlevels

In systemd runlevels are exposed via "target units". You can change them like this:

# systemctl isolate graphical.target

This will only change the current runlevel, and has no effect on the next boot. This is equivalent to commands such as telinit 3 or telinit 5 in Sysvinit.

Change default runlevel/target to boot into

The standard target is default.target, which is aliased by default to graphical.target (which roughly corresponds to the old runlevel 5). To change the default target at boot-time, append one of the following kernel parameters to your bootloader:

  • systemd.unit=multi-user.target (which roughly corresponds to the old runlevel 3),
  • systemd.unit=rescue.target (which roughly corresponds to the old runlevel 1).

Alternatively, you may leave the bootloader alone and change default.target. This can be done using systemctl:

# systemctl enable multi-user.target

The effect of this command is outputted by systemctl; a symlink to the new default target is made at /etc/systemd/system/default.target. This works if, and only if:


is in the target's configuration file. Currently, multi-user.target and graphical.target both have it.

Running DEs under systemd

Using display manager

To enable graphical login, run your preferred Display Manager daemon (e.g. KDM). At the moment, service files exist for GDM, KDM, SLiM, XDM, LXDM and LightDM.

# systemctl enable kdm.service

This should work out of the box. If not, you might have a default.target set manually or from a older install:

# ls -l /etc/systemd/system/default.target
/etc/systemd/system/default.target -> /usr/lib/systemd/system/graphical.target

Simply delete the symlink and systemd will use its stock default.target (i.e. graphical.target).

# rm /etc/systemd/system/default.target

Using service file

Note: Using this method there will be no PAM session created for your user. Therefore ConsoleKit (which gives you access to shutdown/reboot, audio devices etc.) will not work properly. For the recommended way, see: Replacing ConsoleKit with systemd-logind and Automatic_login_to_virtual_console#With_systemd.

If you are only looking for a simple way to start X directly without a display manager, you can create a service file similar to this:

Description=Direct login to X

ExecStart=/bin/su <username> -l -c "/bin/bash --login -c xinit"


Systemd Journal

Since version 38 systemd has an own logging system, the journal.

By default, running a syslog daemon is no longer required. To read the log, use:

# journalctl

The journal writes to /run/systemd/journal, meaning logs will be lost on reboot. For non-volatile logs, create /var/log/journal/:

# mkdir /var/log/journal/

Filtering output

journalctl allows you to filter the output by specific fields.


Show all messages by a specific executable:

# journalctl /usr/lib/systemd/systemd

Show all messages by a specific process:

# journalctl _PID=1

Show all messages by a specific unit:

# journalctl _SYSTEMD_UNIT=netcfg.service

See man journalctl and systemd.journal-fields for details.

Journal size limit

If the journal is made non-volatile, its size limit is set to a default value of 10% of the size of the respective file system. E.g. with /var/log/journal located on a 50 GiB root partition this would lead to 5 GiB of journal data. The maximum size of the persistent journal can be controlled by SystemMaxUse in /etc/systemd/journald.conf, so to limit it for example to 50 MiB uncomment and edit the corresponding line to:


Refer to man journald.conf for more info.

Journald in conjunction with a classic syslog daemon

Compatibility with classic syslog implementations is provided via a socket /run/systemd/journal/syslog, to which all messages are forwarded. To make the syslog daemon work with the journal, it has to bind to this socket instead of /dev/log (official announcement). For syslog-ng, change the source src section in /etc/syslog-ng/syslog-ng.conf to:

source src {

and enable syslog-ng:

# systemctl enable syslog-ng.service


Dynamic (DHCP) with dhcpcd

If you simply want to use DHCP for your Ethernet connection, you can use dhcpcd@.service (provided by the dhcpcd package).

To enable DHCP for eth0, simply use:

# systemctl start dhcpcd@eth0.service

You can enable the service to automatically start at boot with:

# systemctl enable dhcpcd@eth0.service

Sometimes the dhcpd service starts before your network card module (FS#30235), manually add your network card to /etc/modules-load.d/****.conf. Example: create /etc/modules-load.d/r8169.conf, this is a Realtek card:

# r8169

Other configurations

For static, wireless or advanced network configuration like bridging you can use netcfg or NetworkManager which both provide systemd service files.

Note: If you want to use netcfg, networkmanager or another software for managing the network you don't need to start/enable dhcpcd as seen on the previous paragraph.

If you need a static Ethernet configuration, but don't want to use netcfg, there is a custom service file available on the Systemd/Services page.

Arch integration

Initscripts emulation

Integration with Arch's classic configuration is provided by the initscripts package. This is simply meant as a transitional measure to ease users' move to systemd.

Note: /etc/inittab is not used at all.

If you disabled Template:Keypress to reboot in /etc/inittab, you will have to reconfigure this setting for systemd by running systemctl mask ctrl-alt-del.target as root.


Some variables in /etc/rc.conf are respected by this glue work. For a pure systemd setup, it is recommended to use the native systemd configuration files which will take precedence over /etc/rc.conf.

Supported variables:


Not supported variables and systemd configuration:

  • TIMEZONE: Please symlink /etc/localtime to your zoneinfo file manually.
  • HARDWARECLOCK: See Hardware clock time.
  • USELVM: use lvm.service provided by lvm2 instead.

Total conversion to native systemd

Note: This is the preferred method, where the system does not rely on rc.conf centralised configuration anymore, but uses native systemd configuration files.

Follow system configuration as explained in #Native_systemd_configuration_files. Each file replaces one section of /etc/rc.conf as shown in that table:

Configuration Configuration file(s) Legacy /etc/rc.conf section
Hostname /etc/hostname


Console fonts and Keymap /etc/vconsole.conf LOCALIZATION
Locale /etc/locale.conf


Time zone /etc/localtime LOCALIZATION
Hardware clock /etc/adjtime LOCALIZATION
Kernel modules /etc/modules-load.d/ HARDWARE

For legacy purposes, the DAEMONS section in /etc/rc.conf is still compatible with systemd and can be used to start services at boot, even with a "pure" systemd service management. Alternatively, you may remove the /etc/rc.conf file entirely and enable services in systemd. For each <service_name> in the DAEMONS array in /etc/rc.conf, run:

# systemctl enable <service_name>.service
Tip: For a list of commonly used daemons with their initscripts and systemd equivalents, see this table.

If <service_name>.service does not exist:

  • the service file may not be available for systemd. In that case, you'll need to keep rc.conf to start the service during boot up.
  • systemd may name services differently, e.g. cronie.service replaces crond init daemon; alsa-store.service and alsa-restore.service replace the alsa init daemon. Another important instance is the network daemon, which is replaced with another set of service files (see #Network for more details.)
Tip: You may look inside a package that contains daemon start scripts for service names. For instance:
$ pacman -Ql cronie
cronie /etc/rc.d/crond                            #Daemon initscript listed in the DAEMONS array (unused in a "pure" systemd configuration)
cronie /usr/lib/systemd/system/cronie.service     #Corresponding systemd daemon service
  • systemd will automatically handle the start order of these daemons.
  • some services do not need to be explicitly enabled by the user. For instance, dbus.service will automatically be enabled when dbus-core is installed. Check the list of available services and their state using the systemctl command.

Writing custom .service files

Handling dependencies

With systemd, dependencies can be resolved by designing the unit files correctly. The most typical case is that the unit A requires the unit B to be running before A is started. In that case add Requires=B and After=B to the [Unit] section of A. If the dependency is optional, add Wants=B and After=B instead. Note that Wants= and Requires= do not imply After=, meaning that if After= is not specified, the two units will be started in parallel.

Dependencies are typically placed on services and not on targets. For example, network.target is pulled in by whatever service configures your network interfaces, therefore ordering your custom unit after it is sufficient since network.target is started anyway.


There are several different start-up types to consider when writing a custom service file. This is set with the Type= parameter in the [Service] section. See man systemd.service for a more detailed explanation.

  • Type=simple: systemd considers the service to be started up immediately. The process must not fork. Do not use this type if other services need to be ordered on this service, unless it is socket activated.
  • Type=forking: systemd considers the service started up once the process forks and the parent has exited. For classic daemons use this type unless you know that it is not necessary. You should specify PIDFile= as well so systemd can keep track of the main process.
  • Type=oneshot: This is useful for scripts that do a single job and then exit. You may want to set RemainAfterExit= as well so that systemd still considers the service as active after the process has exited.
  • Type=notify: Identical to Type=simple, but with the stipulation that the daemon will send a signal to systemd when it is ready. The reference implementation for this notification is provided by libsystemd-daemon.so.
  • Type=dbus: The service is considered ready when the specified BusName appears on DBus's system bus.

Replacing provided unit files

The unit files in /etc/systemd/system/ take precedence over the ones in /usr/lib/systemd/system/. To make your own version of a unit (which will not be destroyed by an upgrade), copy the old unit file from /usr/lib/ to /etc/ and make your changes there. Alternatively you can use .include to parse an existing service file and then override or add new options. For example, if you simply want to add an additional dependency to a service file, you may use:

.include /usr/lib/systemd/system/<service-name>.service

Requires=<new dependency>
After=<new dependency>

Then run the following for your changes to take effect:

# systemctl reenable <unit>
# systemctl restart <unit>
Tip: You can use systemd-delta to see which unit files have been overridden and what exactly has been changed.

Syntax highlighting for systemd unit files within Vim

Syntax highlighting for systemd unit files within Vim can be enabled by installing vim-systemdAUR from the AUR.


For an up-to-date list of known issues, look at the upstream TODO.















Systemd provides a tool called systemd-analyze that allows you to analyze your boot process so you can see which unit files are causing your boot process to slow down. You can then optimize your system accordingly. You have to install python2-dbus and python2-cairo to use it.

To see how much time was spent in kernel-/userspace on boot, simply use:

$ systemd-analyze
Tip: To see how much time was spent in the initramfs, add the timestamp hook to your HOOKS array in /etc/mkinitcpio.conf and as root, rebuild your initramfs with mkinitcpio -p linux

To list the started unit files, sorted by the time each of them took to start up:

$ systemd-analyze blame

You can also create a SVG file which describes your boot process grapically, similiar to Bootchart:

$ systemd-analyze plot > plot.svg

Enabling bootchart in conjunction with systemd

You can use a version of bootchart to visualize the boot sequence. Since you are not able to put a second init into the kernel command line you won't be able to use any of the standard bootchart setups. However the bootchart2AUR package from AUR comes with an undocumented systemd service. After you've installed bootchart2 do:

# systemctl enable bootchart.service

Read the bootchart documentation for further details on using this version of bootchart.

Shell Shortcuts

systemd daemon management requires a bit more text entry to accomplish tasks such as start, stopped, enabling, checking status, etc. The following functions can be added to one's ~/.bashrc file to help streamline interactions with systemd and to improve the overall experience.

# simplified systemd command, for instance "sudo systemctl stop xxx.service" - > "0.stop xxx"
if ! systemd-notify --booted;
then  # for not systemd
    0.start() {
        sudo rc.d start $1

    0.restart() {
        sudo rc.d restart $1

    0.stop() {
        sudo rc.d stop $1
# start systemd service
    0.start() {
        sudo systemctl start $1.service
# restart systemd service
    0.restart() {
        sudo systemctl restart $1.service
# stop systemd service
    0.stop() {
        sudo systemctl stop $1.service
# enable systemd service
    0.enable() {
        sudo systemctl enable $1.service
# disable a systemd service
    0.disable() {
        sudo systemctl disable $1.service
# show the status of a service
    0.status() {
        systemctl status $1.service
# reload a service configuration
    0.reload() {
        sudo systemctl reload $1.service
# list all running service
    0.list() {
# list all failed service
    0.failed () {
        systemctl --failed
# list all systemd available unit files
    0.list-files() {
        systemctl list-unit-files
# check the log
    0.log() {
        sudo journalctl
# show wants
    0.wants() {
        systemctl show -p "Wants" $1.target
# analyze the system
    0.analyze() {
        systemd-analyze $1

Less output

Change verbose to quiet on the bootloader's kernel line. For some systems, particularly those with an SSD, the slow performance of the TTY is actually a bottleneck, and so less output means faster booting.

Early start

One central feature of systemd is D-Bus and socket activation, this causes services to be started when they are first accessed, and is generally a good thing. However, if you know that a service (like ConsoleKit) will always be started during boot, then the overall boot time might be reduced by starting it as early as possible. This can be achieved (if the service file is set up for it, which in most cases it is) by issuing:

# systemctl enable console-kit-daemon.service

This will cause systemd to start ConsoleKit as soon as possible, without causing races with the socket or D-Bus activation.


The default setup will fsck and mount all filesystems before starting most daemons and services. If you have a large /home partition, it might be better to allow services that do not depend on /home to start while /home is being fsck'ed. This can be achieved by adding the following options to the fstab entry of your /home partition:


This will fsck and mount /home when it is first accessed, and the kernel will buffer all file access to /home until it is ready.

If you have encrypted filesystems with keyfiles, you can also add the noauto parameter to the corresponding entries in /etc/crypttab. systemd will then not open the encrypted device on boot, but instead wait until it is actually accessed and then automatically open it with the specified keyfile before mounting it. This might save a few seconds on boot if you are using an encrypted RAID device for example, because systemd doesn't have to wait for the device to become available. For example:

data /dev/md0 /root/key noauto


systemd comes with its own readahead implementation, this should in principle improve boot time. However, depending on your kernel version and the type of your hard drive, your mileage may vary (i.e. it might be slower). To enable, do:

# systemctl enable systemd-readahead-collect.service systemd-readahead-replay.service

Remember that in order for the readahead to work its magic, you should reboot a couple of times.

Replacing ConsoleKit with systemd-logind

Starting with polkit 0.107 (currently in [testing]), ConsoleKit can be completely replaced by systemd-logind. However, there is currently no Display Manager in the Arch Linux repositories which natively supports systemd-logind without still depending on ConsoleKit. The easiest method to be able to remove ConsoleKit is to automatically login to a virtual console and start X from there. It is important that, as mentioned in the latter article, the X server is started on the same virtual console that you log in to, otherwise systemd can not keep track of the user session. You can then simply remove ck-launch-session from your ~/.xinitrc.

In order to check the status of your user session, you can use loginctl. To see if your user session is properly set up, check if the following command contains Active=yes. All polkit actions like suspending the system or mounting external drives with Udisks should then work automatically.

$ loginctl show-session <session-id>
Note: If you use NetworkManager, you have to recompile it with systemd support from the ABS by setting --with-session-tracking=systemd in the PKGBUILD.


Shutdown/Reboot takes terribly long

If the shutdown process takes a very long time (or seems to freeze) most likely a service not exiting is to blame. systemd waits some time for each service to exit before trying to kill it. To find out if you are affected, see this article.

SLiM and xfce-session

One setup that can produce a shutdown freeze is Xfce in conjunction with SLiM: Shutting down/rebooting using xfce-session will cause slim.service to hang for half a minute until systemd kills it the hard way. One workaround is to create a modified slim.service:

Description=SLiM Simple Login Manager

ExecStart=/usr/bin/slim -d
ExecStop=/bin/kill -9 $MAINPID
ExecStopPost=/bin/rm /var/lock/slim.lock


This causes SLiM to be terminated using SIGKILL. Since the lock file is also removed this does not cause a problem.

If some services are failing to start

If your /var/tmp is a symbolic link to /tmp, expect some services to fail when started via systemd. In these cases, the failure status of the processes (via systemctl status <service>) will be "226/NAMESPACE". To overcome this blocker, simply remove your /var/tmp symlink and reinstall the filesystem package.

See also