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
91 For systemd-bootchart, several proc debug interfaces are required:
99 We recommend to turn off Real-Time group scheduling in the
100 kernel when using systemd. RT group scheduling effectively
101 makes RT scheduling unavailable for most userspace, since it
102 requires explicit assignment of RT budgets to each unit whose
103 processes making use of RT. As there's no sensible way to
104 assign these budgets automatically this cannot really be
105 fixed, and it's best to disable group scheduling hence.
106 CONFIG_RT_GROUP_SCHED=n
108 Note that kernel auditing is broken when used with systemd's
109 container code. When using systemd in conjunction with
110 containers, please make sure to either turn off auditing at
111 runtime using the kernel command line option "audit=0", or
112 turn it off at kernel compile time using:
114 If systemd is compiled with libseccomp support on
115 architectures which do not use socketcall() and where seccomp
116 is supported (this effectively means x86-64 and ARM, but
117 excludes 32-bit x86!), then nspawn will now install a
118 work-around seccomp filter that makes containers boot even
119 with audit being enabled. This works correctly only on kernels
120 3.14 and newer though. TL;DR: turn audit off, still.
124 libmount >= 2.27.1 (from util-linux)
125 libseccomp >= 1.0.0 (optional)
126 libblkid >= 2.24 (from util-linux) (optional)
127 libkmod >= 15 (optional)
128 PAM >= 1.1.2 (optional)
129 libcryptsetup (optional)
132 libselinux (optional)
134 liblz4 >= 119 (optional)
136 libqrencode (optional)
137 libmicrohttpd (optional)
140 elfutils >= 158 (optional)
141 make, gcc, and similar tools
143 During runtime, you need the following additional
146 util-linux >= v2.27.1 required
147 dbus >= 1.4.0 (strictly speaking optional, but recommended)
151 When building from git, the following tools are needed:
162 python-lxml (optional, but required to build the indices)
164 The build system is initialized with ./autogen.sh. A tar ball
166 git archive --format=tar --prefix=systemd-222/ v222 | xz > systemd-222.tar.xz
168 When systemd-hostnamed is used, it is strongly recommended to
169 install nss-myhostname to ensure that, in a world of
170 dynamically changing hostnames, the hostname stays resolvable
171 under all circumstances. In fact, systemd-hostnamed will warn
172 if nss-myhostname is not installed.
175 Default udev rules use the following standard system group
176 names, which need to be resolvable by getgrnam() at any time,
177 even in the very early boot stages, where no other databases
178 and network are available:
180 audio, cdrom, dialout, disk, input, kmem, lp, tape, tty, video
182 During runtime, the journal daemon requires the
183 "systemd-journal" system group to exist. New journal files will
184 be readable by this group (but not writable), which may be used
185 to grant specific users read access. In addition, system
186 groups "wheel" and "adm" will be given read-only access to
187 journal files using systemd-tmpfiles.service.
189 The journal gateway daemon requires the
190 "systemd-journal-gateway" system user and group to
191 exist. During execution this network facing service will drop
192 privileges and assume this uid/gid for security reasons.
194 Similarly, the NTP daemon requires the "systemd-timesync" system
195 user and group to exist.
197 Similarly, the network management daemon requires the
198 "systemd-network" system user and group to exist.
200 Similarly, the name resolution daemon requires the
201 "systemd-resolve" system user and group to exist.
203 Similarly, the kdbus dbus1 proxy daemon requires the
204 "systemd-bus-proxy" system user and group to exist.
206 Similarly, the coredump support requires the
207 "systemd-coredump" system user and group to exist.
210 systemd ships with three NSS modules:
212 nss-myhostname resolves the local hostname to locally
213 configured IP addresses, as well as "localhost" to
216 nss-resolve enables DNS resolution via the systemd-resolved
217 DNS/LLMNR caching stub resolver "systemd-resolved".
219 nss-mymachines enables resolution of all local containers
220 registered with machined to their respective IP addresses.
222 To make use of these NSS modules, please add them to the
223 "hosts: " line in /etc/nsswitch.conf. The "resolve" module
224 should replace the glibc "dns" module in this file.
226 The three modules should be used in the following order:
228 hosts: files mymachines resolve myhostname
231 When calling "systemctl enable/disable/is-enabled" on a unit which is a
232 SysV init.d script, it calls /usr/lib/systemd/systemd-sysv-install;
233 this needs to translate the action into the distribution specific
234 mechanism such as chkconfig or update-rc.d. Packagers need to provide
235 this script if you need this functionality (you don't if you disabled
238 Please see src/systemctl/systemd-sysv-install.SKELETON for how this
239 needs to look like, and provide an implementation at the marked places.
242 systemd will warn you during boot if /usr is on a different
243 file system than /. While in systemd itself very little will
244 break if /usr is on a separate partition, many of its
245 dependencies very likely will break sooner or later in one
246 form or another. For example, udev rules tend to refer to
247 binaries in /usr, binaries that link to libraries in /usr or
248 binaries that refer to data files in /usr. Since these
249 breakages are not always directly visible, systemd will warn
250 about this, since this kind of file system setup is not really
251 supported anymore by the basic set of Linux OS components.
253 systemd requires that the /run mount point exists. systemd also
254 requires that /var/run is a symlink to /run.
256 For more information on this issue consult
257 http://freedesktop.org/wiki/Software/systemd/separate-usr-is-broken
259 To run systemd under valgrind, compile with VALGRIND defined
260 (e.g. ./configure CPPFLAGS='... -DVALGRIND=1'). Otherwise,
261 false positives will be triggered by code which violates
262 some rules but is actually safe.
264 Currently, systemd-timesyncd defaults to use the Google NTP
265 servers if not specified otherwise at configure time. You
266 really should not ship an OS or device with this default
267 setting. See DISTRO_PORTING for details.
269 ENGINEERING AND CONSULTING SERVICES:
270 Kinvolk (https://kinvolk.io) offers professional engineering
271 and consulting services for systemd. Please contact Chris Kühl
272 <chris@kinvolk.io> for more information.