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* Communication channels: alioth project (+ mailing list) and/or a #debian-systemd IRC channel on OFTC | * Communication channels: alioth project (+ mailing list) and/or a [[irc://irc.debian.org/debian-systemd|#debian-systemd]] IRC channel on OFTC |
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Most people interested in systemd development (from diverse distributions) and Debian-specific packaging are around on IRC: #systemd (irc.freenode.net). | Most people interested in systemd development (from diverse distributions) and Debian-specific packaging are around on IRC: [[irc://irc.freenode.net/systemd|#systemd]] (irc.freenode.net). |
Translation(s): none
systemd - system and service manager
Contents
Introduction
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, 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.
Installation
With v20 systemd finally entered unstable (till v19 it is/was available from experimental). systemd requires dbus >=1.4.0, which can be found in testing/wheezy. You have to enhance your sources.list and add unstable Distribution.
To install systemd from unstable:
# apt-get update # apt-get install -t unstable systemd
You also need a kernel with the following options enabled:
- CONFIG_DEVTMPFS=y
- CONFIG_CGROUPS=y
- CONFIG_AUTOFS4_FS=[y|m]
- CONFIG_IPV6=[y|m], optional, but highly recommended
CONFIG_FANOTIFY=y, optional, required for systemd readahed. availabe in Linux kernel >= 2.6.37-rcX. Needs to be enabled for the Debian Linux kernel (605636).
Since v8 the cgroupfs is mounted at /sys/fs/cgroup. This requires a Linux kernel >= 2.6.36 or a backport of this patch.
Debian Linux kernels (>= 2.6.32-23) are suitable.
Debian packages with native systemd support
(>=1.4.0-1) |
testing |
supports socket activation |
|
(>=5.7.1-1) |
testing |
supports socket activation, run systemctl enable rsyslog.service |
|
(>=0.5.14-4) |
testing |
supports D-Bus activation |
|
(>=0.4.3-1) |
testing |
supports D-Bus activation |
|
(>=0.6.28-1) |
testing |
avahi-daemon: supports socket and D-Bus activation, avahi-dnsconfd: started by multi-user.target. Run systemctl enable avahi-daemon.service resp. systemctl enable avahi-dnsconfd.service. |
|
(>=0.8.2-3) |
unstable |
supports D-Bus activation, run systemctl enable NetworkManager.service |
|
(>=165-1) |
testing |
enabled by default, started via basic.target |
|
(>=0.9-3) |
testing |
supports D-Bus activation |
EXAMPLE (here for rsyslog, enable service after installation from Debian/experimental):
# systemctl enable rsyslog.service Output: ln -s '/lib/systemd/system/rsyslog.service' '/etc/systemd/system/multi-user.target.wants/rsyslog.service' ln -s '/lib/systemd/system/rsyslog.socket' '/etc/systemd/system/sockets.target.wants/rsyslog.socket'
Known Issues and Workarounds
Issue #1: sysvinit vs. systemd-sysv
sysvinit is the current default init-system in Debian and is flagged as an "Essential" package. This means the package management tools will refuse to remove or replace the package unless forced. Also on dist-upgrades essential packages are preferred and will be re-installed. For more Details see chapters "3.8 Essential packages" and "5.6.9 Essential"
The systemd-sysv package ships /sbin/init (as a symlink to /bin/systemd) and therefore conflicts with the sysvinit package.
Workaround #1: Do not install systemd-sysv, enhance grub-line (Kernel command line) by "init=/bin/systemd". For a grub2 persistent solution (requires an update-grub to refresh /boot/grub/grub.cfg):
# $EDITOR /etc/default/grub GRUB_CMDLINE_LINUX_DEFAULT="quiet init=/bin/systemd" <--- Change this line # update-grub
Workaround #2: Install systemd-sysv and put package "on hold".
The problem with "Essential flag" needs some discussion with the sysvinit maintainer.
Issue #2: Warning: "/etc/mtab is not a symlink or not pointing to /proc/self/mounts"
This issue is only a warning and can be ignored, we have it on TODO (see below "Make /etc/mtab a symlink to /proc/self/mounts. Requires a newer util-linux package which stores user options separately."). (494001)
The full error-message in dmesg:
[ 5.784886] systemd[1]: /etc/mtab is not a symlink or not pointing to /proc/self/mounts. This is not supported anymore. Please make sure to replace this file by a symlink to avoid incorrect or misleading mount(8) output.
Workaround: Create required symlink:
# ln -sf /proc/self/mounts /etc/mtab
Issue #3: Unsupported fsck -l option in Debian's util-linux
In systemd there are 3 fsck to be considered and have to work together. The fsck binary from util-linux(-ng) package which is a wrapper to the diverse fsck.$FS-Type (for example: fsck.ext4) binaries from e2fsprogs package. Last but not least systemd has its own systemd-fsck implementation. The fsck binary in Debian's util-linux has no support for "-l option", so -l is passed to the fsck.ext4 binary from e2fsprogs which requires "-l filename" (see also e2fsck(8)). This results in systemd-fsck error-code #16 and ending in maintenance mode.
Until the Debian util-linux package has been updated (608120) the Debian systemd package ships a patch to revert this commit "fsck: add new -l switch to fsck mount options".
Issue #4: Dependency cycle in portmap/nfs-common/rpcbind
The nfs-common / portmap / rpcbind SysV init scripts have a dependency cycle which will cause systemd to drop them. You will get an error message during boot like the following:
Found ordering cycle path on basic.target/start Walked on cycle path to sysinit.target/start Walked on cycle path to portmap.service/start Walked on cycle path to basic.target/start Breaking ordering cycle by deleting job portmap.service
Until the portmap / nfs-common / rpcbind init scripts have been fixed, you can get rid of those error messages by uninstalling those packages or fixing their LSB init header manually.
This problem is caused by portmap / nfs-common / rpcbind installing symlinks in both rcS and rc{2345}, see 623377
Issue #5: Shutdown from within KDE sessions does not power off
Workaround: Edit /etc/kde4/kdm/kdmrc, set ?HaltCmd=/sbin/poweroff
This will be fixed in 4.6.3.
See https://bugzilla.novell.com/show_bug.cgi?id=655141 for details.
Note: systemd distinguishes between halt != poweroff. "Halt" really means to halt the machine (see very old U*ix boxes) and power is ON, on the contrary "poweroff" does what the word says. Modern OSes dropped this difference by creating a symlink to halt command (systemd is correct here and KDE "sloppy").
Native mount
With v12 or later you can use native (means systemd's) mount and fsck facility by making sure it is activated in /etc/systemd/system.conf.
# egrep 'MountAuto|SwapAuto' /etc/systemd/system.conf Output: MountAuto=yes SwapAuto=yes
The Debian package enables native mount by default since version 15-1.
If you use Logical-Volume-Manager (LVM) make sure to upgrade your lvm2 package to the latest version available from unstable (>= 2.02.84-1) as it contains important fixes regarding the udev integration. See 603710 for more details. The 19-1 package already does this.
Debugging systemd
Sometimes it is necessary to investigate why systemd hangs on startup or on reboot/shutdown.
EXAMPLE:
- When building a first v15 package a lot of people fell into the "fsck -l pitfall" (see Known Issues #3). Result: systemd-fsck gave back error-code #16 and got into maintenance mode (yay!).
Solution #0: Remove "quiet" from Kernel command line (so called "cmdline" or "grub line")
Solution #1: Increase verbosity via cmdline: Add "systemd.log_target=kmsg systemd.log_level=debug"
Of course you can have a "temporary" persistent solution:
[ /etc/default/grub ] GRUB_CMDLINE_LINUX="systemd.log_target=kmsg systemd.log_level=debug" <--- Add here (by uncommenting you can easily switch to debug) # update-grub
In addition enhance cmdline with "systemd.sysv_console=1" (0: disabled, 1: enabled).
Solution #2: Increase verbosity via /etc/systemd/system.conf
LogLevel=debug <--- Uncomment this line and use "debug" (default: commented and "info") LogTarget=syslog-or-kmsg <--- Uncomment this line (default: commented) SysVConsole=yes <--- Uncomment this line (default: commented)
HINT: "man system" and "man systemd.conf" (Note: File is system.conf vs. man-page system*d*.conf)
HINT: How to check Kernel command line parameters/options?
# cat /proc/cmdline
NOTE on ?LogLevel (see systemd(1) and systemd.conf(5)):
"Set log level. As argument this accepts a numerical log level or the well-known syslog(3) symbolic names (lowercase): emerg, alert, crit, err, warning, notice, info, debug."
HINT: Keep a copy of /sbin/init from sysvinit package in case of rescue (so you can use init=/sbin/init.sysvinit in cmdline)!
# cp -av /sbin/init /sbin/init.sysvinit <--- Before installing systemd-sysv package
Bugs and Bug-Tracking-Systems
- For known bugs please see topic "Known Issues and Workarounds"
TODO
- Update more packages to ship systemd service files.
- Draft a packaging policy involving systemd (upgrade / install / removal).
- Provide integration for package maintainer tools: "dh_systemd"
- invoke-rc.d/update-rc.d/service integration.
- Get Essential flag removed from sysvinit.
- Sort out what to do about pam_loginuid, and integration into the Debian PAM stack
- Decide what to do about group:lock (/var/lock).
- Make /etc/mtab a symlink to /proc/self/mounts. Requires a newer util-linux package which stores user options separately.
- Make systemd-vconsole work. Investigate which of the console-* and kbd* packages are actually required and how to migrate the configuration.
- Migration of /etc/inittab settings.
Collaborative work: Check the whiteboard
- Make /lib/init/rw a symlink to /var/run. For that to work, /var/run needs to be available early, even when /var is on a separate partition. Ubuntu uses a "showthrough" mount option, which is implemented in mountall using mount --bind and --move.
Deprecate /lib/init/rw: http://whiteboard.debian.net/lib-init-rw.wb (Background: systemd-v22 and /run support in general)
Get other syslog implementations updated to support socket activation: https://bugzilla.novell.com/show_bug.cgi?id=656104
WorkInProgress
- Test cryptsetup support.
DONE
- Get libcryptsetup moved to /lib.
- Enable cryptsetup support.
Install a (auto)mount unit to mount /lib/init/rw early during boot. lib-init-rw.automount lib-init-rw.mount unit file.
Future plans
Communication channels: alioth project (+ mailing list) and/or a #debian-systemd IRC channel on OFTC
- Announcement to the Debian mailing-lists: 1. Inform there is sth. awesome 2. Join the systemd party (use it and report, contribute to packaging or even upstream)
Where to get help?
As systemd is a very young project (see [1]), we would appreciate to use the existing upstream infrastructure like mailing-list [2], IRC and read Lennart's blog [3], etc. for following the development. Most people interested in systemd development (from diverse distributions) and Debian-specific packaging are around on IRC: #systemd (irc.freenode.net). Anyway, Debian-specific bugs should be sent to Debian-BTS (for example use report-bug tool).
Who is who?
Maintainer of the systemd package is Tollef Fog Heen (Mithrandir). Currently, it's discussed to get Michael Biebl (mbiebl) as co-maintainer. Michael and Sedat Dilek (dileks) contributed to the initial version of this wiki.
Resources
Talk about systemd in Debian at Linux Plumbers Conference 2010 by Michael Biebl <biebl@debian.org>
References