systemd is a modern sysvinit & RC replacement for Linux systems. It is supported in Gentoo as an alternate init system.
- 1 Pre-installation Configuration
- 2 Installation
- 3 Booting with systemd
- 4 Post Installation Configuration
- 5 Services
- 6 Troubleshooting
- 7 See Also
- 8 External resources
- 9 References
If you're updating from <=sys-apps/systemd-203 check the upgrade subpage.
systemd makes use of many modern Linux kernel features. Right now, the lower bound on kernel version is set in the ebuild to 2.6.39. In recent versions of sys-kernel/gentoo-sources, there is a convenient way of selecting the mandatory and optional kernel options for systemd:
Gentoo Linux ---> Support for init systems, system and service managers ---> [*] systemd
If you wish to configure your Kernel options manually, or do not use sys-kernel/gentoo-sources, the following kernel configuration options are required and recommended:
General setup ---> [*] Control Group support [*] open by fhandle syscalls [ ] Enable deprecated sysfs features to support old userspace tools [*] Configure standard kernel features (expert users) ---> [*] Enable eventpoll support [*] Enable signalfd() system call [*] Enable timerfd() system call [*] Networking support ---> Device Drivers ---> Generic Driver Options ---> [*] Maintain a devtmpfs filesystem to mount at /dev File systems ---> [*] Inotify support for userspace Pseudo filesystems ---> [*] /proc file system support [*] sysfs file system support
General setup ---> [*] Namespaces support ---> [*] Network namespace [*] Enable the block layer ---> [*] Block layer SG support v4 Processor type and features ---> [*] Enable seccomp to safely compute untrusted bytecode Networking support ---> Networking options ---> <*> The IPv6 protocol Device Drivers ---> Generic Driver Options ---> () path to uevent helper [ ] Fallback user-helper invocation for firmware loading Firmware Drivers ---> [*] Export DMI identification via sysfs to userspace File systems ---> <*> Kernel automounter version 4 support (also supports v3) Pseudo filesystems ---> [*] Tmpfs virtual memory file system support (former shm fs) [*] Tmpfs POSIX Access Control Lists [*] Tmpfs extended attributes
For UEFI system you'll also need to enable the following:
[*] Enable the block layer ---> Partition Types ---> [*] Advanced partition selection [*] EFI GUID Partition support Processor type and features ---> [*] EFI runtime service support Firmware Drivers ---> EFI (Extensible Firmware Interface) Support --> <*> EFI Variable Support via sysfs
In the case you are using BFQ scheduler, it's recommended by BFQ upstream to enable "BFQ hierarchical scheduling support" under "Enable the block layer -> IO Schedulers"
For an up-to-date list, see section "REQUIREMENTS" in the upstream README file.
The /run directory
The /run directory is used by systemd and other applications as a non-persistent storage for runtime data like pid files, sockets and state files.
The systemd package will create /run directory itself. However, please note that this change will trigger automatic mounting of it in OpenRC as well, and may trigger using it by different software packages.
Upstream only supports /etc/mtab file being a symlink to /proc/self/mounts. Also not creating this symlink will cause problems with mount (bug #434090) and df (bug #477240). In the past some utilities wrote information (like mount options) into /etc/mtab and thus it was supposed to be file. Currently all software is supposed to avoid this problem but before you do switch check bug #477498 to be sure that you are not affected by any regressions.
To create the symlink, run:
ln -sf /proc/self/mounts /etc/mtab
Ensure /usr is present at boot time
Using LVM2 and Initramfs
genkernel --udev --lvm <target>
When LVM is used, the lvmetad daemon needs to be started as well. Otherwise systemd will be unable to mount LVM volumes. lvmetad can be enabled in /etc/lvm/lvm.conf:
# Set use_lvmetad to '1' for systemd use_lvmetad = 1
Instead of modifying /etc/lvm/lvm.conf this could probably be achieved through a lvmetad.socket unit which activates a lvmetad.service, but current versions of sys-fs/lvm2 don't ship those yet.
- Enable the systemd USE flag globally (make.conf). The consolekit USE flag should also be disabled to prevent conflicts with the systemd-logind service. You can also switch to a systemd subprofile to use saner USE flags defaults not needing to change make.conf:
eselect profile list
Then update your world with the new flags:
emerge -avDN @world
emerge --deselect sys-fs/udev
Booting with systemd
In order to run systemd, you have to switch the init that your executable kernel (or your initramfs) uses.
The services that you have set up in your previous service manager will not be automatically started, this is because you are switching to a different service manager; it order to obtain back functionality like for example the networking or a login manager, you will need to enable and start these services again. More information about this follows in the services section later in this article.
In case your migration yields a broken state, you can always opt to boot back into the default service manager (OpenRC) by undoing this init change step; allowing you to use the troubleshooting section at the end of this article to fix the problem.
The following subsections document how to switch the init in one of the boot managers or the kernel.
Grub Legacy (0.x)
The init=/usr/lib/systemd/systemd argument should be added to the kernel command-line. An example excerpt from grub.conf would look like:
title=Gentoo with systemd root (hd0,0) kernel /vmlinuz root=/dev/sda2 init=/usr/lib/systemd/systemd
Should the system boot using openrc, try using real_init instead of init
If using the grub2-mkconfig configuration generator, add the init option to GRUB_CMDLINE_LINUX (it is not required if using initramfs generated by dracut with systemd inside).
# Append parameters to the linux kernel command line GRUB_CMDLINE_LINUX="init=/usr/lib/systemd/systemd"
If writing a configuration by hand (experts only), append the init parameter to the linux or linux16 command.
linux /vmlinuz-3.10.9 root=UUID=508868e4-54c6-4e6b-84b0-b3b28b1656b6 init=/usr/lib/systemd/systemd
If using genkernel-next's initrd, use real_init instead of init.
In kernel config
You can also set this in your kernel configuration. See "Processor type and features" -> "Built-in kernel command line". Note that this technique works for both grub and grub2.
Setting root password
At this point you might also want to set your root password. If something goes wrong, systemd would prompt for root password to go into maintenance mode.
Post Installation Configuration
systemd supports a few system configuration files to set the most basic system details.
While some system configuration parameters can be updated by modifying the appropriate configuration files, most settings are managed using utilities that require systemd to be running. In this case, it is safe to reboot your computer with systemd and use the hostnamectl, localectl and timedatectl utilities as required.
To set the hostname, create/edit /etc/hostname and simply provide the desired hostname.
When booted using systemd, a tool called hostnamectl exists for editing /etc/hostname and /etc/machine-info. To change hostname, run:
hostnamectl set-hostname <HOSTNAME>
Refer to man hostnamectl for more options.
Usually, you will get your locale properly migrated from openRC when installing systemd. If required, you can set the locale in /etc/locale.conf as per the Handbook instructions:
Once booted with systemd, the tool localectl is used to set locale and console or X11 keymaps. To change the system locale, run the following command.
localectl set-locale LANG=<LOCALE>
To change the virtual console keymap:
localectl set-keymap <KEYMAP>
And finally, to set the X11 layout:
localectl set-x11-keymap <LAYOUT>
If needed you can specify the model, variant and options too:
localectl set-x11-keymap <LAYOUT> <MODEL> <VARIANT> <OPTIONS>
Time & Date
Time and date can be set using the timedatectl utility. Managing the system time before booting with systemd is complex, so it is recommended to leave this until after booting and using the timedatectl utility. It is recommended for systemd-timedated.service to set a symlink from your timezone "/usr/share/zoneinfo/[timezone]" to "/etc/localtime". The ntpdate.service is deprecated and not useable anymore with networkmanger and systemd.
Automatic module loading
Automatic module loading is configured in a different file, or rather directory of files. The configuration files are stored in /etc/modules-load.d. On boot every file with a list of modules will be loaded. The file format is a list of modules seperated by newline and can have any name you want as long as it ends with .conf. You can separate out the module loading by program, service or whatever way you like. My virtualbox.conf example is listed below. But I can imagine one also has an iptables.conf for all the kernel modules needed for your firewall or one big file with all modules.
vboxdrv vboxnetflt vboxnetadp vboxpci
Handling of log files
systemd has its own way of handling log files without needing to rely on any external log system (like syslog-ng or rsyslog). Messages can now be read with journalctl. Anyway, you can still configure it to use your preferred external tool for handling them. Please type man journald.conf for learning about how to configure journald to suit your needs.
/tmp is now in tmpfs
Unless you explicitly mount some other filesystem to /tmp in your fstab, systemd will mount /tmp as tmpfs. That means it will be emptied on every boot and its size will be limited to 50% of your RAM size. To know why this is the desired behavior and how to modify it, take a look at API File Systems
Configure verbosity of boot process
When migrating to systemd you will probably notice differences regarding verbosity of boot process:
- quiet option not only affects to kernel output, but also to systemd itself. Then, while you are setting up systemd for your machine, you will probably want to drop it to see any errors could arise more easily. After that, you can add it back to get a quiet (and faster) boot.
- Even passing quiet option, you can still configure systemd to show its status by also passing systemd.show_status=1.
- When not using quiet option, you could get some messages overwriting consoles, that is caused by kernel configuration (see man 5 proc and look for /proc/sys/kernel/printk). To tweak it you can pass the loglevel=5 boot parameter to the kernel (or a lower value like 1).
At some point you will have to reboot your system in order to get systemd running (in system mode). Be sure to read all of this document to ensure you have systemd configured as completely as possible before rebooting. Note that journalctl(8) works with systemd(8) not running, but that systemctl(8) will not do anything useful without systemd running. You will likely want to complete the service configuration (enabling and starting of services) after you get logged in to your system running systemd.
Although systemd originally intended to support running old init.d scripts, that support is not suited well for a dependency-based RC like OpenRC and thus is completely disabled on Gentoo. OpenRC provides additional measures to ensure that init.d scripts can't be run when OpenRC was not used to boot the system (otherwise the results would be unpredictable).
Listing available services
All available service units can be listed using the list-units verb provided by systemctl:
UNIT LOAD ACTIVE SUB DESCRIPTION boot.automount loaded active waiting EFI System Partition Automount proc-sys-fs-binfmt_misc.automount loaded active waiting Arbitrary Executable File Formats File System Automount Point ...
The following file suffixes are of interest:
- .service - plain service files (e.g. ones just running a daemon directly),
- .socket - socket listeners (much like inetd),
- .path - filesystem triggers for services (running services when files change etc.).
Alternatively, systemctl tool can be used to list all services (including implicit ones):
systemctl --all --full
And finally you can check for services that failed to start running:
Enabling, disabling, starting and stopping services
The usual way of enabling a service is using
systemctl enable foo.service
Services can be disabled likewise:
systemctl disable foo.service
These commands enable services using their default name in default target (both specified in Install section of the service file). However, sometimes services either don't provide that information or you want to use another name/target.
Note that these commands only enable or disable the system to be started on a next boot; if you want to start the service right now, you can use
systemctl start foo.service
Services can be stopped likewise:
systemctl stop foo.service
Installing custom unit files
Custom unit files can be placed in /etc/systemd/system, where they'll be recognized after running:
/usr/lib/systemd/system is reserved for service files installed by the package manager.
Customizing unit files
When only minor changes to a unit are needed, there's no need to create a full copy of the original unit file in /etc/systemd/system Overriding settings in a package management provided unit can be achieved by drop-in files in a *.d directory named after the original unit (e.g. apache2.d) in /etc/systemd/system/.
A reload of systemd is needed to inform it of the changes:
Then the service needs to be restarted to apply the changes:
systemctl restart apache2
Verify, the changed property was applied to the service:
systemctl show --property=MemoryLimit apache2
Enabling a service under a custom name
When the name provided by Alias in the unit's [Install] section does not meet the expectations and providing a permanent new value for this through a customization is not desired, a symlink can be created manually in /etc/systemd/system/*.wants/. The name of the *.wants directory can either specify a target or another service which will depend on the new one.
For example, to install mysqld.service as db.service in the multi-user.target:
ln -s /usr/lib/systemd/system/mysqld.service /etc/systemd/system/multi-user.target.wants/db.service
To disable the service, just remove the symlink:
Some of Gentoo packages already install systemd unit files. For these services, it is enough to enable them. A quick summary of packages installing unit files can be seen on systemd eclass users list.
The following table lists systemd services matching OpenRC ones:
|Gentoo package||OpenRC service||systemd unit||Notes|
|sys-apps/openrc||bootmisc||systemd-tmpfiles-setup.service||always enabled, uses tmpfiles.d|
|consolefont||systemd-vconsole-setup.service||always enabled, uses vconsole.conf|
|fsck||fsck*.service||pulled in implicitly by mounts|
|functions.sh||See note||bug #373219|
|hwclock||See note||always enabled as part of systemd (ie It is baked in and is not a unit)|
|keymaps||systemd-vconsole-setup.service||always enabled, uses vconsole.conf|
|localmount||local-fs.target||actual units are created implicitly from fstab|
|modules||systemd-modules-load.service||always enabled, uses /etc/modules-load.d/*.conf|
|swap||swap.target||actual units are created implicitly from fstab|
|sysctl||systemd-sysctl.service||sysctl.conf and sysctl.d/|
|termencoding||systemd-vconsole-setup.service||always enabled, uses vconsole.conf|
|media-sound/alsa-utils||alsasound||alsa-store.service||(enabled by default)|
|alsa-restore.socket||(enabled by default)|
|net-misc/netifrc||net.*||netctl@.service||net-misc/netctl is originally an Arch Linux tool.|
|NetworkManager.service|| For <networkmanager-0.9.8.4 : enable NetworkManager-dispatcher.service for dispatcher.d scripts to work. |
Enable NetworkManager-wait-online.service to detect that the system has a working internet connection.
Disable all other managers (e.g., wicd, dhcpcd) and wpa_supplicant.
|dhcpcd.service||Provided by net-misc/dhcpcd|
|systemd.networkd.service||Part of systemd|
|net-misc/openssh||sshd||sshd.service||runs sshd as a daemon|
|sshd.socket||runs sshd on a inetd-like basis (for each incoming connection)|
|net-misc/wpa_supplicant||wpa-supplicant||wpa_supplicant.service||D-Bus controlled daemon (e.g. for NetworkManager)|
|wpa_supplicant@.service||interface-specific wpa_supplicant (used like email@example.com)|
|net-print/cups||cupsd||cups.service||classic on-boot start up service|
|cups.socket||socket and path activation (cups only started on-demand)|
|sys-apps/irqbalance||irqbalance||irqbalance.service||supports daemon mode only|
|sys-apps/microcode-ctl||microcode_ctl||Configure microcode as a module to let it load the microcode itself. Go to "Processor type and features" -> "CPU microcode loading support" and remember to add the option you need depending on you having intel or amd processor.|
|udev-mount||(builtin)||/dev is mounted as tmpfs|
|sys-power/acpid||acpid||acpid.service||Most of its functionality is done by systemd itself, then, maybe you could consider to stop enabling this|
|x11-apps/xdm||(xdm)||xdm.service||OpenRC uses common xdm init.d installed by x11-base/xorg-server. With systemd you will need to enable corresponding unit file for each DM (gdm.service, kdm.service...)|
Since version 197 systemd supports timers, making cron unnecessary on a systemd system. Since version 212 persistent services are supported, replacing even anacron. Persistent timers are run at the next opportunity if the system was powered down when the timer was scheduled.
The following is an example on how to make a simple timer that runs in the context of your user. It will even run if the user is not logged in. Every timed service needs a timer and a service file that is activated by the timer as follows:
[Unit] Description=daily backup work RefuseManualStart=no RefuseManualStop=no [Timer] Persistent=false OnCalendar=Mon-Fri *-*-* 11:30:00 Unit=backup-work.service [Install] WantedBy=default.target
[Unit] Description=daily backup work RefuseManualStart=no RefuseManualStop=yes [Service] Type=oneshot ExecStart=/home/<user>/scripts/backup-work.sh
Firstly, you must tell systemd to rescan the service files
systemctl --user daemon-reload
You can trigger the backup manually by running
systemctl --user start backup-work.service
You can start and stop the timer manually by running
systemctl --user start backup-work.timer
systemctl --user stop backup-work.timer
And finally to activate the timer at every system start run
systemctl --user enable backup-work.timer
You can check the last result of running the service with
systemctl --user list-timers
If a timed service runs and fails you can be informed by email. This is possible with the OnFailure stanza that allows you to specify what should happen if a service fails. A failure is detected by a non-zero return code of the backup-work script. For that change the script as follows:
[Unit] Description=daily backup work RefuseManualStart=no RefuseManualStop=yes OnFailure=failure-email@%i.service [Service] Type=oneshot ExecStart=/home/<user>/scripts/backup-work.sh
This requires you to have the service
failure-email@.service installed, which can be found
The above timer and service files can also be added to /usr/lib/systemd/system to make them available system-wide. The install section should then say
WantedBy=multi-user.target to enable the service at system start.
However, cron also runs the scripts in /etc/cron.daily etc. and several packages place scripts there that they expect to be run daily. You can emulate this behaviour with systemd by first installing sys-process/cronbase and then systemd-cron. Just run
./configure --enable-persistent and
make. You can ignore the systemd-crontab-generator stuff if you are only interested in running the files in /etc/cron.daily. Just copy the files from systemd-cron/out/build/units to /usr/lib/systemd/system. Then ensure you adjust the path to
run-parts in the service files. The
run-parts script is located in gentoo in /usr/bin/run-parts. Then activate your new cron replacement with
systemctl enable cron.target
systemctl start cron.target
If you are switching from openrc to systemd and you need lvm to properly mount your volumes, you should activate lvm service:
systemctl enable lvm2-monitor.service
While it might not be needed for activation of root volume, if lvm is integrated into your initramfs, it might not work for other lvm volumes, unless you activate the service.
As systemd-bootchart attempts to start /sbin/init, you may have to edit its configuration file:
... Init=/usr/lib/systemd/systemd ...
Result is a report in svg located in /run/log/.
syslog-ng conflicts with systemd
should be replaced with:
in order to use the syslog-ng service in systemd.unix-dgram('/dev/log');
systemd doesn't seem to respect /etc/conf.d/dmcrypt (bug #429966) and, then, you will need to configure it in /etc/crypttab file:
crypt-home UUID=c25dd0f3-ecdd-420e-99a8-0ff2eaf3f391 -
Check for units that failed to start
To check for units that failed to start you can run:
Enable Debug Mode
To get more informations you need to set the following in /etc/systemd/system.conf:
Or enable the debug-shell, that opens an terminal at tty9. This help to debug such service during boot process.
systemctl enable debug-shell.service
Please remember to edit /etc/e4rat.conf setting 'init' to /usr/lib/systemd/systemd, otherwise it will keep booting openrc.
Synopsis: systemd-networkd log error
could not find udev device: Permission denied
The error raises due to systemd-networkd works under non-root user.
You should set kernel option CONFIG_GRKERNSEC_SYSFS_RESTRICT=N.
- Comparison of init systems
- Sakaki's EFI Install Guide (particularly, this chapter)
- OpenRC to Systemd Cheatsheet
- Jose Pedro Oliveira. Note about custom syslog-ng configurations files, Red Hat Bugzilla, January 11, 2012. Retrieved on January 12th, 2015
- Systemd and syslog-ng interaction problems: system freezes / syslog-ng fails to start, Fedora Project Wiki. Retrieved on January 12th, 2015