https://wiki.archlinux.org/api.php?action=feedcontributions&user=Doak&feedformat=atomArchWiki - User contributions [en]2024-03-29T12:51:15ZUser contributionsMediaWiki 1.41.0https://wiki.archlinux.org/index.php?title=Systemd&diff=342118Systemd2014-10-27T13:22:37Z<p>Doak: The correct pattern seems to be 'MESSAGE' (uppercase).</p>
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<div>{{Lowercase title}}<br />
[[Category:Daemons and system services]]<br />
[[Category:Boot process]]<br />
[[ar:Systemd]]<br />
[[de:Systemd]]<br />
[[el:Systemd]]<br />
[[es:Systemd]]<br />
[[fr:Systemd]]<br />
[[it:Systemd]]<br />
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{{Related articles start}}<br />
{{Related|systemd/User}}<br />
{{Related|systemd/Services}}<br />
{{Related|systemd/Timers}}<br />
{{Related|systemd FAQ}}<br />
{{Related|init}}<br />
{{Related|init Rosetta}}<br />
{{Related|Daemons List}}<br />
{{Related|udev}}<br />
{{Related|Improve boot performance}}<br />
{{Related|Allow users to shutdown}}<br />
{{Related articles end}}<br />
<br />
From the [http://freedesktop.org/wiki/Software/systemd project web page]:<br />
<br />
:''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 [[cgroups|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.<br />
<br />
{{Note|1=For a detailed explanation as to why Arch has moved to ''systemd'', see [https://bbs.archlinux.org/viewtopic.php?pid=1149530#p1149530 this forum post].}}<br />
<br />
== Basic systemctl usage ==<br />
<br />
The main command used to introspect and control ''systemd'' is ''systemctl''. Some of its uses are examining the system state and managing the system and services. See {{ic|man 1 systemctl}} for more details.<br />
<br />
{{Tip|You can use all of the following ''systemctl'' commands with the {{ic|-H ''user''@''host''}} switch to control a ''systemd'' instance on a remote machine. This will use [[SSH]] to connect to the remote ''systemd'' instance.}}<br />
<br />
{{Note|''systemadm'' is the official graphical frontend for ''systemctl''. It is provided by {{Pkg|systemd-ui}} from the [[official repositories]] or by {{AUR|systemd-ui-git}} from the [[AUR]] for the development version.}}<br />
<br />
=== Analyzing the system state ===<br />
<br />
List running units:<br />
<br />
$ systemctl<br />
<br />
or:<br />
<br />
$ systemctl list-units<br />
<br />
List failed units:<br />
<br />
$ systemctl --failed<br />
<br />
The available unit files can be seen in {{ic|/usr/lib/systemd/system/}} and {{ic|/etc/systemd/system/}} (the latter takes precedence). You can see a list of the installed unit files with:<br />
<br />
$ systemctl list-unit-files<br />
<br />
=== Using units ===<br />
<br />
Units can be, for example, services (''.service''), mount points (''.mount''), devices (''.device'') or sockets (''.socket'').<br />
<br />
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 short forms when specifying the unit in the following ''systemctl'' commands:<br />
<br />
* If you do not specify the suffix, systemctl will assume ''.service''. For example, {{ic|netcfg}} and {{ic|netcfg.service}} are equivalent.<br />
* Mount points will automatically be translated into the appropriate ''.mount'' unit. For example, specifying {{ic|/home}} is equivalent to {{ic|home.mount}}.<br />
* Similar to mount points, devices are automatically translated into the appropriate ''.device'' unit, therefore specifying {{ic|/dev/sda2}} is equivalent to {{ic|dev-sda2.device}}.<br />
<br />
See {{ic|man systemd.unit}} for details.<br />
<br />
{{Note|Some unit names contain an {{ic|@}} sign (e.g. {{ic|name@''string''.service}}): this means that they are [http://0pointer.de/blog/projects/instances.html instances] of a ''template'' unit, whose actual file name does not contain the {{ic|''string''}} part (e.g. {{ic|name@.service}}). {{ic|''string''}} is called the ''instance identifier'', and is similar to an argument that is passed to the template unit when called with the ''systemctl'' command: in the unit file it will substitute the {{ic|%i}} specifier. <br />
<br />
To be more accurate, ''before'' trying to instantiate the {{ic|name@.suffix}} template unit, ''systemd'' will actually look for a unit with the exact {{ic|name@string.suffix}} file name, although by convention such a "clash" happens rarely, i.e. most unit files containing an {{ic|@}} sign are meant to be templates. Also, if a template unit is called without an instance identifier, it will just fail, since the {{ic|%i}} specifier cannot be substituted.<br />
}}<br />
<br />
{{Tip|Most of the following commands also work if multiple units are specified, see {{ic|man systemctl}} for more information.}}<br />
<br />
Activate a unit immediately:<br />
<br />
# systemctl start ''unit''<br />
<br />
Deactivate a unit immediately:<br />
<br />
# systemctl stop ''unit''<br />
<br />
Restart a unit:<br />
<br />
# systemctl restart ''unit''<br />
<br />
Ask a unit to reload its configuration:<br />
<br />
# systemctl reload ''unit''<br />
<br />
Show the status of a unit, including whether it is running or not:<br />
<br />
$ systemctl status ''unit''<br />
<br />
Check whether a unit is already enabled or not:<br />
<br />
$ systemctl is-enabled ''unit''<br />
<br />
Enable a unit to be started on bootup:<br />
<br />
# systemctl enable ''unit''<br />
<br />
Disable a unit to not start during bootup:<br />
<br />
# systemctl disable ''unit''<br />
<br />
Show the manual page associated with a unit (this has to be supported by the unit file):<br />
<br />
$ systemctl help ''unit''<br />
<br />
Reload ''systemd'', scanning for new or changed units:<br />
<br />
# systemctl daemon-reload<br />
<br />
=== Power management ===<br />
<br />
[[polkit]] is necessary for power management as an unprivileged user. If you are in a local ''systemd-logind'' 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.<br />
<br />
Shut down and reboot the system:<br />
<br />
$ systemctl reboot<br />
<br />
Shut down and power-off the system:<br />
<br />
$ systemctl poweroff<br />
<br />
Suspend the system:<br />
<br />
$ systemctl suspend<br />
<br />
Put the system into hibernation:<br />
<br />
$ systemctl hibernate<br />
<br />
Put the system into hybrid-sleep state (or suspend-to-both):<br />
<br />
$ systemctl hybrid-sleep<br />
<br />
== Writing unit files ==<br />
<br />
The syntax of ''systemd'''s [http://www.freedesktop.org/software/systemd/man/systemd.unit.html unit files] is inspired by XDG Desktop Entry Specification ''.desktop'' files, which are in turn inspired by Microsoft Windows ''.ini'' files. Unit files are loaded from two locations. From lowest to highest precedence they are:<br />
<br />
* {{ic|/usr/lib/systemd/system/}}: units provided by installed packages<br />
* {{ic|/etc/systemd/system/}}: units installed by the system administrator<br />
<br />
{{Note|The load paths are completely different when running ''systemd'' in [[systemd/User#How it works|user mode]].}}<br />
<br />
Look at the units installed by your packages for examples, or see [[systemd/Services]].<br />
<br />
{{Tip|Comments prepended with {{ic|#}} may be used in unit-files as well, but only in new lines. Do not use end-line comments after ''systemd'' parameters or the unit will fail to activate.}}<br />
<br />
=== Handling dependencies ===<br />
<br />
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 {{ic|1=Requires=''B''}} and {{ic|1=After=''B''}} to the {{ic|[Unit]}} section of ''A''. If the dependency is optional, add {{ic|1=Wants=''B''}} and {{ic|1=After=''B''}} instead. Note that {{ic|1=Wants=}} and {{ic|1=Requires=}} do not imply {{ic|1=After=}}, meaning that if {{ic|1=After=}} is not specified, the two units will be started in parallel.<br />
<br />
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.<br />
<br />
=== Service types ===<br />
<br />
There are several different start-up types to consider when writing a custom service file. This is set with the {{ic|1=Type=}} parameter in the {{ic|[Service]}} section:<br />
<br />
* {{ic|1=Type=simple}} (default): ''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.<br />
* {{ic|1=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 {{ic|1=PIDFile=}} as well so ''systemd'' can keep track of the main process.<br />
* {{ic|1=Type=oneshot}}: this is useful for scripts that do a single job and then exit. You may want to set {{ic|1=RemainAfterExit=yes}} as well so that ''systemd'' still considers the service as active after the process has exited.<br />
* {{ic|1=Type=notify}}: identical to {{ic|1=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''.<br />
* {{ic|1=Type=dbus}}: the service is considered ready when the specified {{ic|BusName}} appears on DBus's system bus.<br />
* {{ic|1=Type=idle}}: behavior of idle is very similar to {{ic|1=Type=simple}}; however, actual execution of the service binary is delayed until all jobs are dispatched. This may be used to avoid interleaving of output of shell services with the status output on the console.<br />
<br />
See {{ic|man systemd.service}} for a more detailed explanation.<br />
<br />
=== Editing provided unit files ===<br />
<br />
To edit a unit file provided by a package, you can create a directory called {{ic|/etc/systemd/system/''unit''.d/}} for example {{ic|/etc/systemd/system/httpd.service.d/}} and place ''*.conf'' files in there to override or add new options. ''systemd'' will parse these ''*.conf'' files and apply them on top of the original unit. For example, if you simply want to add an additional dependency to a unit, you may create the following file:<br />
<br />
{{hc|/etc/systemd/system/''unit''.d/customdependency.conf|2=<br />
[Unit]<br />
Requires=''new dependency''<br />
After=''new dependency''<br />
}}<br />
<br />
As another example, in order to replace the {{ic|ExecStart}} directive for a unit that is not of type {{ic|oneshot}}, create the following file:<br />
<br />
{{hc|/etc/systemd/system/''unit''.d/customexec.conf|2=<br />
[Service]<br />
ExecStart=<br />
ExecStart=''new command''<br />
}}<br />
<br />
Note how {{ic|ExecStart}} must be cleared before being re-assigned ([https://bugzilla.redhat.com/show_bug.cgi?id=756787#c9]).<br />
<br />
One more example to automatically restart a service:<br />
<br />
{{hc|/etc/systemd/system/''unit''.d/restart.conf|2=<br />
[Service]<br />
Restart=always<br />
RestartSec=30<br />
}}<br />
<br />
Then run the following for your changes to take effect:<br />
<br />
# systemctl daemon-reload<br />
# systemctl restart ''unit''<br />
<br />
Alternatively you can copy the old unit file from {{ic|/usr/lib/systemd/system/}} to {{ic|/etc/systemd/system/}} and make your changes there. A unit file in {{ic|/etc/systemd/system/}} always overrides the same unit in {{ic|/usr/lib/systemd/system/}}. Note that when the original unit in {{ic|/usr/lib/}} is changed due to a package upgrade, these changes will not automatically apply to your custom unit file in {{ic|/etc/}}. Additionally you will have to manually reenable the unit with {{ic|systemctl reenable ''unit''}}. It is therefore recommended to use the ''*.conf'' method described before instead.<br />
<br />
{{Note|You can use '''systemd-delta''' to see which unit files have been overridden and what exactly has been changed. Doing so regularly is important for system maintenance as well, to check updates the provided unit files may have received.}}<br />
<br />
{{Tip|Syntax highlighting for ''systemd'' unit files within [[Vim]] can be enabled by installing {{Pkg|vim-systemd}} from the [[official repositories]].}}<br />
<br />
== Targets ==<br />
<br />
''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 ''target''s 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 {{ic|telinit RUNLEVEL}} command.<br />
<br />
=== Get current targets ===<br />
<br />
The following should be used under ''systemd'' instead of running {{ic|runlevel}}:<br />
<br />
$ systemctl list-units --type=target<br />
<br />
=== Create custom target ===<br />
<br />
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 {{ic|/etc/systemd/system/''your target''}} that takes one of the existing runlevels as a base (you can look at {{ic|/usr/lib/systemd/system/graphical.target}} as an example), make a directory {{ic|/etc/systemd/system/''your target''.wants}}, and then symlink the additional services from {{ic|/usr/lib/systemd/system/}} that you wish to enable.<br />
<br />
=== Targets table ===<br />
<br />
{| class="wikitable"<br />
! SysV Runlevel !! systemd Target !! Notes<br />
|-<br />
| 0 || runlevel0.target, poweroff.target || Halt the system.<br />
|-<br />
| 1, s, single || runlevel1.target, rescue.target || Single user mode.<br />
|-<br />
| 2, 4 || runlevel2.target, runlevel4.target, multi-user.target || User-defined/Site-specific runlevels. By default, identical to 3.<br />
|-<br />
| 3 || runlevel3.target, multi-user.target || Multi-user, non-graphical. Users can usually login via multiple consoles or via the network.<br />
|-<br />
| 5 || runlevel5.target, graphical.target || Multi-user, graphical. Usually has all the services of runlevel 3 plus a graphical login.<br />
|-<br />
| 6 || runlevel6.target, reboot.target || Reboot<br />
|-<br />
| emergency || emergency.target || Emergency shell<br />
|-<br />
|}<br />
<br />
=== Change current target ===<br />
<br />
In ''systemd'' targets are exposed via ''target units''. You can change them like this:<br />
<br />
# systemctl isolate graphical.target<br />
<br />
This will only change the current target, and has no effect on the next boot. This is equivalent to commands such as {{ic|telinit 3}} or {{ic|telinit 5}} in Sysvinit.<br />
<br />
=== Change default target to boot into ===<br />
<br />
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:<br />
<br />
* {{ic|1=systemd.unit=multi-user.target}} (which roughly corresponds to the old runlevel 3),<br />
* {{ic|1=systemd.unit=rescue.target}} (which roughly corresponds to the old runlevel 1).<br />
<br />
Alternatively, you may leave the bootloader alone and change ''default.target''. This can be done using ''systemctl'':<br />
<br />
# systemctl set-default multi-user.target<br />
<br />
To be able to override the previously set ''default.target'', use the force option:<br />
<br />
# systemctl set-default -f multi-user.target<br />
<br />
The effect of this command is output by ''systemctl''; a symlink to the new default target is made at {{ic|/etc/systemd/system/default.target}}.<br />
<br />
== Temporary files ==<br />
<br />
"''systemd-tmpfiles'' creates, deletes and cleans up volatile and temporary files and directories." It reads configuration files in {{ic|/etc/tmpfiles.d/}} and {{ic|/usr/lib/tmpfiles.d/}} to discover which actions to perform. Configuration files in the former directory take precedence over those in the latter directory.<br />
<br />
Configuration files are usually provided together with service files, and they are named in the style of {{ic|/usr/lib/tmpfiles.d/''program''.conf}}. For example, the [[Samba]] daemon expects the directory {{ic|/run/samba}} to exist and to have the correct permissions. Therefore, the {{Pkg|samba}} package ships with this configuration:<br />
<br />
{{hc|/usr/lib/tmpfiles.d/samba.conf|<br />
D /run/samba 0755 root root}}<br />
<br />
Configuration files may also be used to write values into certain files on boot. For example, if you used {{ic|/etc/rc.local}} to disable wakeup from USB devices with {{ic|echo USBE > /proc/acpi/wakeup}}, you may use the following tmpfile instead:<br />
<br />
{{hc|/etc/tmpfiles.d/disable-usb-wake.conf|<br />
w /proc/acpi/wakeup - - - - USBE}}<br />
<br />
See the {{ic|systemd-tmpfiles(8)}} and {{ic|tmpfiles.d(5)}} man pages for details.<br />
<br />
{{Note|This method may not work to set options in {{ic|/sys}} since the ''systemd-tmpfiles-setup'' service may run before the appropriate device modules is loaded. In this case you could check whether the module has a parameter for the option you want to set with {{ic|modinfo ''module''}} and set this option with a [[Kernel modules#Configuration|config file in /etc/modprobe.d]]. Otherwise you will have to write a [[Udev#About_udev_rules|udev rule]] to set the appropriate attribute as soon as the device appears.}}<br />
<br />
== Timers ==<br />
<br />
A timer is a unit configuration file whose name ends with ''.timer'' and encodes information about a timer controlled and supervised by ''systemd'', for timer-based activation. See [[systemd/Timers]].<br />
<br />
{{Note|Timers can replace ''cron'' functionality to a great extent. See [[systemd/Timers#As a cron replacement]].}}<br />
<br />
== Journal ==<br />
<br />
''systemd'' has its own logging system called the journal; therefore, running a {{ic|syslog}} daemon is no longer required. To read the log, use:<br />
<br />
# journalctl<br />
<br />
In Arch Linux, the directory {{ic|/var/log/journal/}} is a part of the {{Pkg|systemd}} package, and the journal (when {{ic|1=Storage=}} is set to {{ic|auto}} in {{ic|/etc/systemd/journald.conf}}) will write to {{ic|/var/log/journal/}}. If you or some program delete that directory, ''systemd'' will '''not''' recreate it automatically; however, it will be recreated during the next update of the ''systemd'' package. Until then, logs will be written to {{ic|/run/systemd/journal}}, and logs will be lost on reboot.<br />
<br />
{{Tip|If {{ic|/var/log/journal/}} resides in a [[btrfs]] file system, you should consider disabling Copy-on-Write for the directory. See the main article for details: [[Btrfs#Copy-On-Write (CoW)]].}}<br />
<br />
=== Filtering output ===<br />
<br />
''journalctl'' allows you to filter the output by specific fields. Be aware that if there are many messages to display or filtering of large time span has to be done, the output of this command can be delayed for quite some time.<br />
<br />
{{Tip|While the journal is stored in a binary format, the content of stored messages is not modified. This means it is viewable with ''strings'', for example for recovery in an environment which does not have ''systemd'' installed. Example command:<br />
{{ic|$ strings /mnt/arch/var/log/journal/af4967d77fba44c6b093d0e9862f6ddd/system.journal <nowiki>| grep -i</nowiki> ''message''}}<br />
}}<br />
<br />
Examples:<br />
<br />
* Show all messages from this boot: {{bc|# journalctl -b}} However, often one is interested in messages not from the current, but from the previous boot (e.g. if an unrecoverable system crash happened). This is possible through optional offset parameter of the {{ic|-b}} flag: {{ic|journalctl -b -0}} shows messages from the current boot, {{ic|journalctl -b -1}} from the previous boot, {{ic|journalctl -b -2}} from the second previous and so on. See {{ic|man 1 journalctl}} for full description, the semantics is much more powerful.<br />
* Show all messages from date (and optional time): {{bc|1=# journalctl --since="2012-10-30 18:17:16"}}<br />
* Show all messages since 20 minutes ago: {{bc|1=# journalctl --since "20 min ago"}}<br />
* Follow new messages: {{bc|# journalctl -f}}<br />
* Show all messages by a specific executable: {{bc|# journalctl /usr/lib/systemd/systemd}}<br />
* Show all messages by a specific process: {{bc|1=# journalctl _PID=1}}<br />
* Show all messages by a specific unit: {{bc|# journalctl -u netcfg}}<br />
* Show kernel ring buffer: {{bc|1=# journalctl -k}}<br />
<br />
See {{ic|man 1 journalctl}}, {{ic|man 7 systemd.journal-fields}}, or Lennart's [http://0pointer.de/blog/projects/journalctl.html blog post] for details.<br />
<br />
{{Tip|1=<br />
By default, ''journalctl'' truncates lines longer than screen width, but in some cases, it may be better to enable wrapping instead of truncating. This can be controlled by the {{ic|SYSTEMD_LESS}} [[Environment variables|environment variable]], which contains options passed to [[Core utilities#less|less]] (the default pager) and defaults to {{ic|FRSXMK}} (see {{ic|man 1 less}} and {{ic|man 1 journalctl}} for details).<br />
<br />
By omitting the {{ic|S}} option, the output will be wrapped instead of truncated. For example, start ''journalctl'' as follows:<br />
<br />
$ SYSTEMD_LESS=FRXMK journalctl<br />
<br />
If you'd like set this behaviour as default, [[Environment variables#Defining variables locally|export]] the variable from {{ic|~/.bashrc}} or {{ic|~/.zshrc}}.<br />
}}<br />
<br />
=== Journal size limit ===<br />
<br />
If the journal is persistent (non-volatile), its size limit is set to a default value of 10% of the size of the respective file system. For example, with {{ic|/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 {{ic|SystemMaxUse}} in {{ic|/etc/systemd/journald.conf}}, so to limit it for example to 50 MiB uncomment and edit the corresponding line to:<br />
<br />
SystemMaxUse=50M<br />
<br />
Refer to {{ic|man journald.conf}} for more info.<br />
<br />
=== Journald in conjunction with syslog ===<br />
<br />
Compatibility with a classic [[Syslog-ng|syslog]] implementation can be provided by letting ''systemd'' forward all messages via the socket {{ic|/run/systemd/journal/syslog}}. To make the syslog daemon work with the journal, it has to bind to this socket instead of {{ic|/dev/log}} ([http://lwn.net/Articles/474968/ official announcement]). The {{Pkg|syslog-ng}} package in the repositories automatically provides the necessary configuration. <br />
<br />
As of ''systemd'' 216 the default {{ic|journald.conf}} for forwarding to the socket is {{ic|no}}. This means you will need to set the option {{ic|1=ForwardToSyslog=yes}} in {{ic|/etc/systemd/journald.conf}} to actually use ''syslog-ng'' with ''journald''. See [[Syslog-ng#Overview]] for details. <br />
<br />
If you use {{Pkg|rsyslog}} instead, it is not necessary to change the option because [[rsyslog]] pulls the messages from the journal by [http://lists.freedesktop.org/archives/systemd-devel/2014-August/022295.html#journald itself].<br />
<br />
=== Forward journald to /dev/tty12 ===<br />
<br />
In {{ic|/etc/systemd/journald.conf}} enable the following:<br />
<br />
ForwardToConsole=yes<br />
TTYPath=/dev/tty12<br />
MaxLevelConsole=info<br />
<br />
Restart journald with:<br />
<br />
# systemctl restart systemd-journald<br />
<br />
== Troubleshooting ==<br />
<br />
=== Investigating systemd errors ===<br />
<br />
As an example, we will investigate an error with {{ic|systemd-modules-load}} service:<br />
<br />
'''1.''' Lets find the ''systemd'' services which fail to start:<br />
<br />
{{hc|1=$ systemctl --state=failed|2=<br />
systemd-modules-load.service loaded '''failed failed''' Load Kernel Modules<br />
}}<br />
<br />
'''2.''' Ok, we found a problem with {{ic|systemd-modules-load}} service. We want to know more:<br />
{{hc|$ systemctl status systemd-modules-load|2=<br />
systemd-modules-load.service - Load Kernel Modules<br />
Loaded: loaded (/usr/lib/systemd/system/systemd-modules-load.service; static)<br />
Active: '''failed''' (Result: exit-code) since So 2013-08-25 11:48:13 CEST; 32s ago<br />
Docs: man:systemd-modules-load.service(8).<br />
man:modules-load.d(5)<br />
Process: '''15630''' ExecStart=/usr/lib/systemd/systemd-modules-load ('''code=exited, status=1/FAILURE''')<br />
}}<br />
If the {{ic|Process ID}} is not listed, just restart the failed service with {{ic|systemctl restart systemd-modules-load}}<br />
<br />
'''3.''' Now we have the process id (PID) to investigate this error in depth. Enter the following command with the current {{ic|Process ID}} (here: 15630):<br />
{{hc|1=$ journalctl -b _PID=15630|2=<br />
-- Logs begin at Sa 2013-05-25 10:31:12 CEST, end at So 2013-08-25 11:51:17 CEST. --<br />
Aug 25 11:48:13 mypc systemd-modules-load[15630]: '''Failed to find module 'blacklist usblp''''<br />
Aug 25 11:48:13 mypc systemd-modules-load[15630]: '''Failed to find module 'install usblp /bin/false'''' <br />
}}<br />
<br />
'''4.''' We see that some of the kernel module configs have wrong settings. Therefore we have a look at these settings in {{ic|/etc/modules-load.d/}}:<br />
{{hc|$ ls -Al /etc/modules-load.d/|<br />
...<br />
-rw-r--r-- 1 root root 79 1. Dez 2012 blacklist.conf<br />
-rw-r--r-- 1 root root 1 2. Mär 14:30 encrypt.conf<br />
-rw-r--r-- 1 root root 3 5. Dez 2012 printing.conf<br />
-rw-r--r-- 1 root root 6 14. Jul 11:01 realtek.conf<br />
-rw-r--r-- 1 root root 65 2. Jun 23:01 virtualbox.conf<br />
...<br />
}}<br />
<br />
'''5.''' The {{ic|Failed to find module 'blacklist usblp'}} error message might be related to a wrong setting inside of {{ic|blacklist.conf}}. Lets deactivate it with inserting a trailing '''#''' before each option we found via step 3:<br />
{{hc|/etc/modules-load.d/blacklist.conf|<br />
'''#''' blacklist usblp<br />
'''#''' install usblp /bin/false<br />
}}<br />
<br />
'''6.''' Now, try to start {{ic|systemd-modules-load}}:<br />
$ systemctl start systemd-modules-load<br />
If it was successful, this should not prompt anything. If you see any error, go back to step 3 and use the new PID for solving the errors left.<br />
<br />
If everything is ok, you can verify that the service was started successfully with:<br />
{{hc|$ systemctl status systemd-modules-load|2=<br />
systemd-modules-load.service - Load Kernel Modules<br />
Loaded: '''loaded''' (/usr/lib/systemd/system/systemd-modules-load.service; static)<br />
Active: '''active (exited)''' since So 2013-08-25 12:22:31 CEST; 34s ago<br />
Docs: man:systemd-modules-load.service(8)<br />
man:modules-load.d(5)<br />
Process: 19005 ExecStart=/usr/lib/systemd/systemd-modules-load (code=exited, status=0/SUCCESS)<br />
Aug 25 12:22:31 mypc systemd[1]: '''Started Load Kernel Modules'''.<br />
}}<br />
<br />
Often you can solve these kind of problems like shown above. For further investigation look at [[#Diagnosing boot problems]].<br />
<br />
=== Diagnosing boot problems ===<br />
<br />
Boot with these parameters on the kernel command line:<br />
{{ic|<nowiki>systemd.log_level=debug systemd.log_target=kmsg log_buf_len=1M</nowiki>}}<br />
<br />
[http://freedesktop.org/wiki/Software/systemd/Debugging More Debugging Information].<br />
<br />
=== Diagnosing problems with a specific service ===<br />
<br />
If some ''systemd'' service misbehaves and you want to get more information about what is going on, set the {{ic|SYSTEMD_LOG_LEVEL}} [[environment variable]] to {{ic|debug}}. For example, to run the ''systemd-networkd'' daemon in debug mode:<br />
<br />
# systemctl stop systemd-networkd<br />
# SYSTEMD_LOG_LEVEL=debug /lib/systemd/systemd-networkd<br />
<br />
Or, equivalently, modify the service file temporarily for gathering enough output. For example: <br />
<br />
{{hc|/lib/systemd/system/systemd-networkd.service|2=<br />
[Service]<br />
...<br />
Environment=SYSTEMD_LOG_LEVEL=debug<br />
....<br />
}}<br />
<br />
If debug information is required long-term, add the variable the [[#Editing provided unit files|regular]] way.<br />
<br />
=== Shutdown/reboot takes terribly long ===<br />
<br />
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 [http://freedesktop.org/wiki/Software/systemd/Debugging/#shutdowncompleteseventually this article].<br />
<br />
=== Short lived processes do not seem to log any output ===<br />
<br />
If {{ic|journalctl -u foounit}} does not show any output for a short lived service, look at the PID instead. For example, if {{ic|systemd-modules-load.service}} fails, and {{ic|systemctl status systemd-modules-load}} shows that it ran as PID 123, then you might be able to see output in the journal for that PID, i.e. {{ic|journalctl -b _PID&#61;123}}. Metadata fields for the journal such as _SYSTEMD_UNIT and _COMM are collected asynchronously and rely on the {{ic|/proc}} directory for the process existing. Fixing this requires fixing the kernel to provide this data via a socket connection, similar to SCM_CREDENTIALS.<br />
<br />
=== Disabling application crash dumps journaling ===<br />
<br />
Edit the file {{ic|/etc/systemd/coredump.conf}} by adding this line:<br />
<br />
Storage=none<br />
<br />
and reboot your system.<br />
<br />
=== Error message on reboot or shutdown ===<br />
<br />
==== cgroup : option or name mismatch, new: 0x0 "", old: 0x4 "systemd" ====<br />
<br />
See [https://bbs.archlinux.org/viewtopic.php?pid=1372562#p1372562 this thread] for an explanation.<br />
<br />
==== watchdog watchdog0: watchdog did not stop! ====<br />
<br />
See [https://bbs.archlinux.org/viewtopic.php?pid=1372562#p1372562 this thread] for an explanation.<br />
<br />
=== Boot time increasing over time ===<br />
<br />
After using {{ic|systemd-analyze}} a number of users have noticed that their boot time has increased significantly in comparison with what it used to be. After using {{ic|systemd-analyze blame}} [[NetworkManager]] is being reported as taking an unusually large amount of time to start. <br />
<br />
The problem for some users has been due to {{ic|/var/log/journal}} becoming too large. This may have other impacts on performance, such as for {{ic|systemctl status}} or {{ic|journalctl}}. As such the solution is to remove every file within the folder (ideally making a backup of it somewhere, at least temporarily) and then setting a journal file size limit as described in [[#Journal size limit]].<br />
<br />
== See also ==<br />
<br />
*[http://www.freedesktop.org/wiki/Software/systemd Official web site]<br />
*[[Wikipedia:systemd|Wikipedia article]]<br />
*[http://0pointer.de/public/systemd-man/ Manual pages]<br />
*[http://freedesktop.org/wiki/Software/systemd/Optimizations systemd optimizations]<br />
*[http://www.freedesktop.org/wiki/Software/systemd/FrequentlyAskedQuestions FAQ]<br />
*[http://www.freedesktop.org/wiki/Software/systemd/TipsAndTricks Tips and tricks]<br />
*[http://0pointer.de/public/systemd-ebook-psankar.pdf systemd for Administrators (PDF)]<br />
*[http://fedoraproject.org/wiki/Systemd About systemd on Fedora Project]<br />
*[http://fedoraproject.org/wiki/How_to_debug_Systemd_problems How to debug systemd problems]<br />
*[http://www.h-online.com/open/features/Control-Centre-The-systemd-Linux-init-system-1565543.html Two] [http://www.h-online.com/open/features/Booting-up-Tools-and-tips-for-systemd-1570630.html part] introductory article in ''The H Open'' magazine.<br />
*[http://0pointer.de/blog/projects/systemd.html Lennart's blog story]<br />
*[http://0pointer.de/blog/projects/systemd-update.html Status update]<br />
*[http://0pointer.de/blog/projects/systemd-update-2.html Status update2]<br />
*[http://0pointer.de/blog/projects/systemd-update-3.html Status update3]<br />
*[http://0pointer.de/blog/projects/why.html Most recent summary]<br />
*[http://fedoraproject.org/wiki/SysVinit_to_Systemd_Cheatsheet Fedora's SysVinit to systemd cheatsheet]<br />
*[http://wiki.gentoo.org/wiki/Systemd Gentoo Wiki systemd page]</div>Doakhttps://wiki.archlinux.org/index.php?title=Netctl&diff=255884Netctl2013-05-02T18:39:44Z<p>Doak: Added note to use 'wpa-configsection' if automatic profile selection is desired.</p>
<hr />
<div>{{Lowercase title}}<br />
[[Category:Networking]]<br />
[[fr:Netctl]]<br />
[[es:Netctl]]<br />
[[ja:Netctl]]<br />
[[zh-CN:Netctl]]<br />
[[ru:Netctl]]<br />
{{Article summary start}}<br />
{{Article summary text|A guide to configuring the network using netctl and network profile scripts.}}<br />
{{Article summary end}}<br />
Netctl is a new Arch project that replaces [[netcfg]]. Netctl is the future (and present) of CLI-based network management on Arch Linux.<br />
<br />
==Installation==<br />
The {{Pkg|netctl}} package is available in the [[Official Repositories]]. Installing netctl will replace {{pkg|netcfg}}.<br />
<br />
==Required reading==<br />
Considerable effort has gone into the construction of quality man pages. Users should read the following man pages prior to using netctl:<br />
*[https://github.com/joukewitteveen/netctl/blob/master/docs/netctl.1.txt netctl]<br />
*[https://github.com/joukewitteveen/netctl/blob/master/docs/netctl.profile.5.txt netctl.profile]<br />
*[https://github.com/joukewitteveen/netctl/blob/master/docs/netctl.special.7.txt netctl.special]<br />
<br />
{{Pkg|netctl}} and {{Pkg|netcfg}} are conflicting packages. You will be potentially connectionless after installing {{Pkg|netctl}} '''if''' your profiles are misconfigured.<br />
<br />
==Configuration==<br />
<br />
{{ic|netctl}} may be used to introspect and control the state of the systemd services for the network profile manager. Example configuration files are provided for the user to assist them in configuring their network connection. These example profiles are located in {{ic|/etc/netctl/examples/}}. The common configurations include:<br />
*ethernet-dhcp<br />
*ethernet-static<br />
*wireless-wpa<br />
*wireless-wpa-static<br />
<br />
To use an example profile, simply copy one of them from {{ic|/etc/netctl/examples/}} to {{ic|/etc/netctl/}} and configure it to your needs:<br />
# cp /etc/netctl/examples/wireless-wpa /etc/netctl/<br />
<br />
Once you have created your profile, make an attempt to establish a connection using the newly created profile by running:<br />
# netctl start <profile><br />
<br />
If issuing the above command results in a failure, then use {{ic|journalctl -xn}} and {{ic|netctl status <profile>}} in order to obtain a more in depth explanation of the failure. Make the needed corrections to the failed configuration and retest.<br />
<br />
===Automatic Operation===<br />
====Just One Profile====<br />
If you are using only one profile, once that profile is started successfully, it can be {{ic|enabled}} using <br />
# netctl enable <profile> <br />
This will create and enable a [[systemd]] service that will start when the computer boots.<br />
<br />
{{Note|The connection to a dhcp-server is only established, if the interface is connected and up at boot time (or when the service starts). In order to have an automatic connection established on cable connect, proceed to the [[Netctl#Multiple_Profiles|Multiple Profiles]] section.}}<br />
<br />
====Multiple Profiles====<br />
Whereas with {{ic|netcfg}} there was {{ic|net-auto-wireless.service}} and {{ic|net-auto-wired.service}}, {{ic|netctl}} uses {{ic|netctl-auto@<interface>.service}} for wireless profiles, and {{ic|netctl-ifplugd@<interface>.service}} for wired profiles. In order to make the {{ic|netctl-auto@<interface>.service}} work for wireless interfaces, the package {{pkg|wpa_actiond}} is required to be installed. In order to make the {{ic|netctl-ifplugd@<interface>.service}} work for wired interfaces, the package {{pkg|ifplugd}} is required to be installed. Configure {{ic|/etc/ifplugd/ifplugd.conf}} accordingly. Automatic selection of a WPA-enabled profile by netctl-auto is not possible with option {{ic|1=Security=wpa-config}}, please use {{ic|1=Security=wpa-configsection}} instead.<br />
<br />
Once your profiles are set and verified to be working, simply enable these services with <br />
# systemctl enable netctl-auto@<interface>.service <br />
# systemctl enable netctl-ifplugd@<interface>.service <br />
<br />
If you have previously enabled a profile through {{ic|netctl}}, run <br />
# netctl disable <profile> <br />
to prevent the profile from starting twice at boot, and possibly causing issues with wpa_supplicant.<br />
<br />
{{Note|If there is ever a need to alter a currently enabled profile, execute {{ic|netctl reenable <profile>}} to apply the changes.}}<br />
<br />
===Migrating from netcfg===<br />
{{Warning|{{ic|netctl}} conflicts with {{ic|netcfg}} so disable existing {{ic|netcfg@<profile>}} service before installing {{ic|netctl}}.}}<br />
<br />
{{ic|netctl}} uses {{ic|/etc/netctl}} to store its profiles, ''not'' {{ic|/etc/network.d}} ({{ic|netcfg}}'s profile storage location).<br />
<br />
In order to migrate from netcfg, at least the following is needed:<br />
*Move network profile files to the new directory.<br />
*Rename variables therein according to netctl.profile(5) (Most variable names have only UpperCamelCase i.e CONNECTION= becomes Connection=).<br />
*For static IP configuration make sure the Address= variables have a netmask after the IP (e.g. Address=('192.168.1.23<b>/24</b>' '192.168.1.87<b>/24</b>') in the example profile). <br />
*If you setup a wireless profile according in the {{ic|wireless-wpa-configsection}} example, note that this overrides {{ic|wpa_supplicant}} options defined above the brackets. For a connection to a hidden wireless network, add {{ic|scan_ssid<nowiki>=1</nowiki>}} to the options in the {{ic|wireless-wpa-configsection}}; {{ic|Hidden<nowiki>=</nowiki>yes}} does not work there. <br />
*Unquote interface variables and other variables that don't strictly need quoting (this is mainly a style thing).<br />
*Run {{ic|netctl enable <profile>}} for every profile in the old NETWORKS array. 'last' doesn't work this way, see netctl.special(7).<br />
*Use {{ic|netctl list}} / {{ic|netctl start <profile>}} instead of netcfg-menu. wifi-menu remains available.<br />
<br />
===Passphrase obfuscation (256-bit PSK)===<br />
<br />
Users ''not'' wishing to have their passphrase stored in ''plain text'' have the option of storing the corresponding 256-bit PSK instead, which is calculated from the passphrase and the SSID using standard algorithms.<br />
<br />
Calculate your 256-bit PSK using [[WPA_supplicant#Configuration_file|wpa_passphrase]]:<br />
{{hc|Usage: wpa_passphrase [ssid] [passphrase]|<br />
2=$ wpa_passphrase archlinux freenode|<br />
network={<br />
ssid="archlinux"<br />
#psk="freenode"<br />
psk=64cf3ced850ecef39197bb7b7b301fc39437a6aa6c6a599d0534b16af578e04a<br />
}<br />
{{Note|This information will be used in your profile so do not close the terminal}}<br />
}}<br />
<br />
In a second terminal window copy the example file {{ic|wireless-wpa}} from {{ic|/etc/netctl/examples}} to {{ic|/etc/netctl}}.<br />
# cp /etc/netctl/examples/wireless-wpa /etc/netctl/wireless-wpa<br />
<br />
You will then need to edit {{ic|/etc/netctl/wireless-wpa}} using your favorite text editor and add the ''Pre-shared Key'' that was generated earlier using wpa_passphrase, to the {{ic|'''Key'''}} variable of this profile.<br />
<br />
Once completed your network profile {{ic|wireless-wpa}} containing a 256-bit PSK should resemble:<br />
{{hc|/etc/netctl/wireless-wpa|2=<br />
Description='A simple WPA encrypted wireless connection using 256-bit PSK'<br />
Interface=wlp2s2<br />
Connection=wireless<br />
Security=wpa<br />
IP=dhcp<br />
ESSID=archlinux<br />
Key=\"64cf3ced850ecef39197bb7b7b301fc39437a6aa6c6a599d0534b16af578e04a<br />
}}<br />
{{Note|1=Make sure to use the '''special non-quoted rules''' for {{ic|1=Key=}} that are explained at the end of [https://github.com/joukewitteveen/netctl/blob/master/docs/netctl.profile.5.txt netctl.profile(5)].}}<br />
{{Note|1=The key that you put in the profile configuration is enough to connect to a WPA-PSK network, which means this procedure is only good to hide the human-readable passphrase, but will not prevent anyone with read access to this file from connecting to the network. You should ask yourself if there is any use in this at all, since using the same passphrase for anything else is a very poor security measure.}}<br />
<br />
==Support==<br />
Official announcement thread: https://bbs.archlinux.org/viewtopic.php?id=157670<br />
<br />
==Tips and Tricks==<br />
As of April 2013 there is no netctl alternative to {{ic|netcfg current}}. If you relied on it for something, like a status bar for a tiling window manager, you can now use:<br />
# netctl list | sed -n 's/^\* //p'<br />
or, when {{ic|netctl-auto}} was used to connect:<br />
# wpa_cli -i <interface> status | sed -n 's/^id_str=//p'</div>Doak