+systemd System and Service Manager
-udev - a userspace implementation of devfs
+DETAILS:
+ http://0pointer.de/blog/projects/systemd.html
-For more information on the design, and structure of this project, see the
-files in the docs/ directory.
+WEB SITE:
+ http://www.freedesktop.org/wiki/Software/systemd
-To use:
+GIT:
+ git@github.com:systemd/systemd.git
+ https://github.com/systemd/systemd.git
-- You must be running a 2.6 version of the Linux kernel.
+GITWEB:
+ https://github.com/systemd/systemd
-- Make sure sysfs is mounted. udev will figure out where sysfs is mounted, but
- the traditional place for it is at /sys. You can mount it by hand by running:
- mount -t sysfs none /sys
+MAILING LIST:
+ http://lists.freedesktop.org/mailman/listinfo/systemd-devel
+ http://lists.freedesktop.org/mailman/listinfo/systemd-commits
-- Make sure you have the latest version of the linux-hotplug scripts. They are
- available at linux-hotplug.sf.net or from your local kernel.org mirror at:
- kernel.org/pub/linux/utils/kernel/hotplug/
- They are required in order for udev to work properly.
+IRC:
+ #systemd on irc.freenode.org
- If for some reason you do not install the hotplug scripts, you must tell the
- kernel to point the hotplug binary at wherever you install udev at. This can
- be done by:
- echo "/sbin/udev" > /proc/sys/kernel/hotplug
+BUG REPORTS:
+ https://github.com/systemd/systemd/issues
-- Build the project:
- make
+AUTHOR:
+ Lennart Poettering
+ Kay Sievers
+ ...and many others
- Note:
- There are a number of different flags that you can use when building
- udev. They are as follows:
- prefix - set this to the default root that you want udev to be
- installed into. This works just like the 'configure --prefix'
- script does. Default value is ''. Only override this if you
- really know what you are doing.
- USE_KLIBC - if set to 'true', udev is built and linked against the included
- version of klibc. Default value is 'false'.
- DEBUG - if set to 'true', debugging messages will be sent to the syslog
- as udev is run. Default value is 'false'.
- USE_DBUS - if set to 'true', DBUS messages will be sent everytime udev
- creates or removes a device node. This requires that DBUS
- development headers and libraries be present on your system to
- build properly. Default value is 'false'.
+LICENSE:
+ LGPLv2.1+ for all code
+ - except src/basic/MurmurHash2.c which is Public Domain
+ - except src/basic/siphash24.c which is CC0 Public Domain
+ - except src/journal/lookup3.c which is Public Domain
+ - except src/udev/* which is (currently still) GPLv2, GPLv2+
- So, if you want to build udev using klibc with debugging messages, you
- would do:
- make USE_KLIBC=true DEBUG=true
+REQUIREMENTS:
+ Linux kernel >= 3.7
+ Linux kernel >= 3.8 for Smack support
+ Kernel Config Options:
+ CONFIG_DEVTMPFS
+ CONFIG_CGROUPS (it is OK to disable all controllers)
+ CONFIG_INOTIFY_USER
+ CONFIG_SIGNALFD
+ CONFIG_TIMERFD
+ CONFIG_EPOLL
+ CONFIG_NET
+ CONFIG_SYSFS
+ CONFIG_PROC_FS
+ CONFIG_FHANDLE (libudev, mount and bind mount handling)
-- Install the project:
- make install
+ udev will fail to work with the legacy sysfs layout:
+ CONFIG_SYSFS_DEPRECATED=n
- This will put the udev binary in /sbin, create the /udev and /etc/udev
- directories, and place the udev configuration files in /etc/udev. You
- will probably want to edit the namedev.* files to create custom naming
- rules. More info on how the config files are set up are contained in
- comments in the files, and is located in the documentation.
+ Legacy hotplug slows down the system and confuses udev:
+ CONFIG_UEVENT_HELPER_PATH=""
-- Add and remove devices from the system and marvel as nodes are created
- and removed in /udev/ based on the device types.
+ Userspace firmware loading is not supported and should
+ be disabled in the kernel:
+ CONFIG_FW_LOADER_USER_HELPER=n
-- If you later get sick of it, uninstall it:
- make uninstall
+ Some udev rules and virtualization detection relies on it:
+ CONFIG_DMIID
+ Support for some SCSI devices serial number retrieval, to
+ create additional symlinks in /dev/disk/ and /dev/tape:
+ CONFIG_BLK_DEV_BSG
-Things are still quite rough, and it's a bit beyond proof of concept
-code. Help is very much appreciated, see the TODO file for a list of
-things left to be done.
+ Required for PrivateNetwork and PrivateDevices in service units:
+ CONFIG_NET_NS
+ CONFIG_DEVPTS_MULTIPLE_INSTANCES
+ Note that systemd-localed.service and other systemd units use
+ PrivateNetwork and PrivateDevices so this is effectively required.
-If you want to build using klibc, use the Makefile.klibc file:
- - read the klibc/klibc/README file for how to set up the linux
- symlink properly.
- - make clean
- - make -f Makefile.klibc
-and marvel at the tiny binary you just created :)
+ Optional but strongly recommended:
+ CONFIG_IPV6
+ CONFIG_AUTOFS4_FS
+ CONFIG_TMPFS_XATTR
+ CONFIG_{TMPFS,EXT4,XFS,BTRFS_FS,...}_POSIX_ACL
+ CONFIG_SECCOMP
+ CONFIG_CHECKPOINT_RESTORE (for the kcmp() syscall)
-Any comment/questions/concerns please let me know.
+ Required for CPUShares= in resource control unit settings
+ CONFIG_CGROUP_SCHED
+ CONFIG_FAIR_GROUP_SCHED
-greg k-h
-greg@kroah.com
+ Required for CPUQuota= in resource control unit settings
+ CONFIG_CFS_BANDWIDTH
+ For systemd-bootchart, several proc debug interfaces are required:
+ CONFIG_SCHEDSTATS
+ CONFIG_SCHED_DEBUG
+ For UEFI systems:
+ CONFIG_EFIVAR_FS
+ CONFIG_EFI_PARTITION
+ We recommend to turn off Real-Time group scheduling in the
+ kernel when using systemd. RT group scheduling effectively
+ makes RT scheduling unavailable for most userspace, since it
+ requires explicit assignment of RT budgets to each unit whose
+ processes making use of RT. As there's no sensible way to
+ assign these budgets automatically this cannot really be
+ fixed, and it's best to disable group scheduling hence.
+ CONFIG_RT_GROUP_SCHED=n
+
+ Note that kernel auditing is broken when used with systemd's
+ container code. When using systemd in conjunction with
+ containers, please make sure to either turn off auditing at
+ runtime using the kernel command line option "audit=0", or
+ turn it off at kernel compile time using:
+ CONFIG_AUDIT=n
+ If systemd is compiled with libseccomp support on
+ architectures which do not use socketcall() and where seccomp
+ is supported (this effectively means x86-64 and ARM, but
+ excludes 32-bit x86!), then nspawn will now install a
+ work-around seccomp filter that makes containers boot even
+ with audit being enabled. This works correctly only on kernels
+ 3.14 and newer though. TL;DR: turn audit off, still.
+
+ glibc >= 2.16
+ libcap
+ libmount >= 2.20 (from util-linux)
+ libseccomp >= 1.0.0 (optional)
+ libblkid >= 2.24 (from util-linux) (optional)
+ libkmod >= 15 (optional)
+ PAM >= 1.1.2 (optional)
+ libcryptsetup (optional)
+ libaudit (optional)
+ libacl (optional)
+ libselinux (optional)
+ liblzma (optional)
+ liblz4 >= 119 (optional)
+ libgcrypt (optional)
+ libqrencode (optional)
+ libmicrohttpd (optional)
+ libpython (optional)
+ libidn (optional)
+ elfutils >= 158 (optional)
+ make, gcc, and similar tools
+
+ During runtime, you need the following additional
+ dependencies:
+
+ util-linux >= v2.26 required
+ dbus >= 1.4.0 (strictly speaking optional, but recommended)
+ dracut (optional)
+ PolicyKit (optional)
+
+ When building from git, the following tools are needed:
+
+ pkg-config
+ docbook-xsl
+ xsltproc
+ automake
+ autoconf
+ libtool
+ intltool
+ gperf
+ python (optional)
+ python-lxml (optional, but required to build the indices)
+ sphinx (optional)
+
+ The build system is initialized with ./autogen.sh. A tar ball
+ can be created with:
+ git archive --format=tar --prefix=systemd-222/ v222 | xz > systemd-222.tar.xz
+
+ When systemd-hostnamed is used, it is strongly recommended to
+ install nss-myhostname to ensure that, in a world of
+ dynamically changing hostnames, the hostname stays resolvable
+ under all circumstances. In fact, systemd-hostnamed will warn
+ if nss-myhostname is not installed.
+
+ To build HTML documentation for python-systemd using sphinx,
+ please first install systemd (using 'make install'), and then
+ invoke sphinx-build with 'make sphinx-<target>', with <target>
+ being 'html' or 'latexpdf'. If using DESTDIR for installation,
+ pass the same DESTDIR to 'make sphinx-html' invocation.
+
+USERS AND GROUPS:
+ Default udev rules use the following standard system group
+ names, which need to be resolvable by getgrnam() at any time,
+ even in the very early boot stages, where no other databases
+ and network are available:
+
+ audio, cdrom, dialout, disk, input, kmem, lp, tape, tty, video
+
+ During runtime, the journal daemon requires the
+ "systemd-journal" system group to exist. New journal files will
+ be readable by this group (but not writable), which may be used
+ to grant specific users read access. In addition, system
+ groups "wheel" and "adm" will be given read-only access to
+ journal files using systemd-tmpfiles.service.
+
+ The journal gateway daemon requires the
+ "systemd-journal-gateway" system user and group to
+ exist. During execution this network facing service will drop
+ privileges and assume this uid/gid for security reasons.
+
+ Similarly, the NTP daemon requires the "systemd-timesync" system
+ user and group to exist.
+
+ Similarly, the network management daemon requires the
+ "systemd-network" system user and group to exist.
+
+ Similarly, the name resolution daemon requires the
+ "systemd-resolve" system user and group to exist.
+
+ Similarly, the kdbus dbus1 proxy daemon requires the
+ "systemd-bus-proxy" system user and group to exist.
+
+NSS:
+ systemd ships with three NSS modules:
+
+ nss-myhostname resolves the local hostname to locally
+ configured IP addresses, as well as "localhost" to
+ 127.0.0.1/::1.
+
+ nss-resolve enables DNS resolution via the systemd-resolved
+ DNS/LLMNR caching stub resolver "systemd-resolved".
+
+ nss-mymachines enables resolution of all local containers
+ registered with machined to their respective IP addresses.
+
+ To make use of these NSS modules, please add them to the
+ "hosts: " line in /etc/nsswitch.conf. The "resolve" module
+ should replace the glibc "dns" module in this file.
+
+ The three modules should be used in the following order:
+
+ hosts: files mymachines resolve myhostname
+
+SYSV INIT.D SCRIPTS:
+ When calling "systemctl enable/disable/is-enabled" on a unit which is a
+ SysV init.d script, it calls /usr/lib/systemd/systemd-sysv-install;
+ this needs to translate the action into the distribution specific
+ mechanism such as chkconfig or update-rc.d. Packagers need to provide
+ this script if you need this functionality (you don't if you disabled
+ SysV init support).
+
+ Please see src/systemctl/systemd-sysv-install.SKELETON for how this
+ needs to look like, and provide an implementation at the marked places.
+
+WARNINGS:
+ systemd will warn you during boot if /etc/mtab is not a
+ symlink to /proc/mounts. Please ensure that /etc/mtab is a
+ proper symlink.
+
+ systemd will warn you during boot if /usr is on a different
+ file system than /. While in systemd itself very little will
+ break if /usr is on a separate partition, many of its
+ dependencies very likely will break sooner or later in one
+ form or another. For example, udev rules tend to refer to
+ binaries in /usr, binaries that link to libraries in /usr or
+ binaries that refer to data files in /usr. Since these
+ breakages are not always directly visible, systemd will warn
+ about this, since this kind of file system setup is not really
+ supported anymore by the basic set of Linux OS components.
+
+ systemd requires that the /run mount point exists. systemd also
+ requires that /var/run is a symlink to /run.
+
+ For more information on this issue consult
+ http://freedesktop.org/wiki/Software/systemd/separate-usr-is-broken
+
+ To run systemd under valgrind, compile with VALGRIND defined
+ (e.g. ./configure CPPFLAGS='... -DVALGRIND=1'). Otherwise,
+ false positives will be triggered by code which violates
+ some rules but is actually safe.
+
+ Currently, systemd-timesyncd defaults to use the Google NTP
+ servers if not specified otherwise at configure time. You
+ really should not ship an OS or device with this default
+ setting. See DISTRO_PORTING for details.