1 systemd System and Service Manager
4 http://0pointer.de/blog/projects/systemd.html
7 http://www.freedesktop.org/wiki/Software/systemd
10 git@github.com:systemd/systemd.git
11 https://github.com/systemd/systemd.git
14 https://github.com/systemd/systemd
17 http://lists.freedesktop.org/mailman/listinfo/systemd-devel
20 #systemd on irc.freenode.org
23 https://github.com/systemd/systemd/issues
31 LGPLv2.1+ for all code
32 - except src/basic/MurmurHash2.c which is Public Domain
33 - except src/basic/siphash24.c which is CC0 Public Domain
34 - except src/journal/lookup3.c which is Public Domain
35 - except src/udev/* which is (currently still) GPLv2, GPLv2+
39 Linux kernel >= 4.2 for unified cgroup hierarchy support
41 Kernel Config Options:
43 CONFIG_CGROUPS (it is OK to disable all controllers)
51 CONFIG_FHANDLE (libudev, mount and bind mount handling)
53 udev will fail to work with the legacy sysfs layout:
54 CONFIG_SYSFS_DEPRECATED=n
56 Legacy hotplug slows down the system and confuses udev:
57 CONFIG_UEVENT_HELPER_PATH=""
59 Userspace firmware loading is not supported and should
60 be disabled in the kernel:
61 CONFIG_FW_LOADER_USER_HELPER=n
63 Some udev rules and virtualization detection relies on it:
66 Support for some SCSI devices serial number retrieval, to
67 create additional symlinks in /dev/disk/ and /dev/tape:
70 Required for PrivateNetwork and PrivateDevices in service units:
72 CONFIG_DEVPTS_MULTIPLE_INSTANCES
73 Note that systemd-localed.service and other systemd units use
74 PrivateNetwork and PrivateDevices so this is effectively required.
76 Optional but strongly recommended:
80 CONFIG_{TMPFS,EXT4,XFS,BTRFS_FS,...}_POSIX_ACL
82 CONFIG_CHECKPOINT_RESTORE (for the kcmp() syscall)
84 Required for CPUShares= in resource control unit settings
86 CONFIG_FAIR_GROUP_SCHED
88 Required for CPUQuota= in resource control unit settings
95 We recommend to turn off Real-Time group scheduling in the
96 kernel when using systemd. RT group scheduling effectively
97 makes RT scheduling unavailable for most userspace, since it
98 requires explicit assignment of RT budgets to each unit whose
99 processes making use of RT. As there's no sensible way to
100 assign these budgets automatically this cannot really be
101 fixed, and it's best to disable group scheduling hence.
102 CONFIG_RT_GROUP_SCHED=n
104 Note that kernel auditing is broken when used with systemd's
105 container code. When using systemd in conjunction with
106 containers, please make sure to either turn off auditing at
107 runtime using the kernel command line option "audit=0", or
108 turn it off at kernel compile time using:
110 If systemd is compiled with libseccomp support on
111 architectures which do not use socketcall() and where seccomp
112 is supported (this effectively means x86-64 and ARM, but
113 excludes 32-bit x86!), then nspawn will now install a
114 work-around seccomp filter that makes containers boot even
115 with audit being enabled. This works correctly only on kernels
116 3.14 and newer though. TL;DR: turn audit off, still.
120 libmount >= 2.27.1 (from util-linux)
121 (util-linux *must* be built with --enable-libmount-force-mountinfo)
122 libseccomp >= 1.0.0 (optional)
123 libblkid >= 2.24 (from util-linux) (optional)
124 libkmod >= 15 (optional)
125 PAM >= 1.1.2 (optional)
126 libcryptsetup (optional)
129 libselinux (optional)
131 liblz4 >= 119 (optional)
133 libqrencode (optional)
134 libmicrohttpd (optional)
137 elfutils >= 158 (optional)
138 make, gcc, and similar tools
140 During runtime, you need the following additional
143 util-linux >= v2.27.1 required
144 dbus >= 1.4.0 (strictly speaking optional, but recommended)
148 When building from git, the following tools are needed:
159 python-lxml (optional, but required to build the indices)
161 The build system is initialized with ./autogen.sh. A tar ball
163 git archive --format=tar --prefix=systemd-222/ v222 | xz > systemd-222.tar.xz
165 When systemd-hostnamed is used, it is strongly recommended to
166 install nss-myhostname to ensure that, in a world of
167 dynamically changing hostnames, the hostname stays resolvable
168 under all circumstances. In fact, systemd-hostnamed will warn
169 if nss-myhostname is not installed.
172 Default udev rules use the following standard system group
173 names, which need to be resolvable by getgrnam() at any time,
174 even in the very early boot stages, where no other databases
175 and network are available:
177 audio, cdrom, dialout, disk, input, kmem, lp, tape, tty, video
179 During runtime, the journal daemon requires the
180 "systemd-journal" system group to exist. New journal files will
181 be readable by this group (but not writable), which may be used
182 to grant specific users read access. In addition, system
183 groups "wheel" and "adm" will be given read-only access to
184 journal files using systemd-tmpfiles.service.
186 The journal gateway daemon requires the
187 "systemd-journal-gateway" system user and group to
188 exist. During execution this network facing service will drop
189 privileges and assume this uid/gid for security reasons.
191 Similarly, the NTP daemon requires the "systemd-timesync" system
192 user and group to exist.
194 Similarly, the network management daemon requires the
195 "systemd-network" system user and group to exist.
197 Similarly, the name resolution daemon requires the
198 "systemd-resolve" system user and group to exist.
200 Similarly, the coredump support requires the
201 "systemd-coredump" system user and group to exist.
204 systemd ships with three NSS modules:
206 nss-myhostname resolves the local hostname to locally
207 configured IP addresses, as well as "localhost" to
210 nss-resolve enables DNS resolution via the systemd-resolved
211 DNS/LLMNR caching stub resolver "systemd-resolved".
213 nss-mymachines enables resolution of all local containers
214 registered with machined to their respective IP addresses.
216 To make use of these NSS modules, please add them to the
217 "hosts: " line in /etc/nsswitch.conf. The "resolve" module
218 should replace the glibc "dns" module in this file.
220 The three modules should be used in the following order:
222 hosts: files mymachines resolve myhostname
225 When calling "systemctl enable/disable/is-enabled" on a unit which is a
226 SysV init.d script, it calls /usr/lib/systemd/systemd-sysv-install;
227 this needs to translate the action into the distribution specific
228 mechanism such as chkconfig or update-rc.d. Packagers need to provide
229 this script if you need this functionality (you don't if you disabled
232 Please see src/systemctl/systemd-sysv-install.SKELETON for how this
233 needs to look like, and provide an implementation at the marked places.
236 systemd will warn you during boot if /usr is on a different
237 file system than /. While in systemd itself very little will
238 break if /usr is on a separate partition, many of its
239 dependencies very likely will break sooner or later in one
240 form or another. For example, udev rules tend to refer to
241 binaries in /usr, binaries that link to libraries in /usr or
242 binaries that refer to data files in /usr. Since these
243 breakages are not always directly visible, systemd will warn
244 about this, since this kind of file system setup is not really
245 supported anymore by the basic set of Linux OS components.
247 systemd requires that the /run mount point exists. systemd also
248 requires that /var/run is a symlink to /run.
250 For more information on this issue consult
251 http://freedesktop.org/wiki/Software/systemd/separate-usr-is-broken
253 To run systemd under valgrind, compile with VALGRIND defined
254 (e.g. ./configure CPPFLAGS='... -DVALGRIND=1'). Otherwise,
255 false positives will be triggered by code which violates
256 some rules but is actually safe.
258 Currently, systemd-timesyncd defaults to use the Google NTP
259 servers if not specified otherwise at configure time. You
260 really should not ship an OS or device with this default
261 setting. See DISTRO_PORTING for details.
263 ENGINEERING AND CONSULTING SERVICES:
264 Kinvolk (https://kinvolk.io) offers professional engineering
265 and consulting services for systemd. Please contact Chris Kühl
266 <chris@kinvolk.io> for more information.