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 Required for PrivateUsers= in service units:
79 Optional but strongly recommended:
83 CONFIG_{TMPFS,EXT4,XFS,BTRFS_FS,...}_POSIX_ACL
85 CONFIG_SECCOMP_FILTER (required for seccomp support)
86 CONFIG_CHECKPOINT_RESTORE (for the kcmp() syscall)
88 Required for CPUShares= in resource control unit settings
90 CONFIG_FAIR_GROUP_SCHED
92 Required for CPUQuota= in resource control unit settings
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 (util-linux *must* be built with --enable-libmount-force-mountinfo)
126 libseccomp >= 2.3.1 (optional)
127 libblkid >= 2.24 (from util-linux) (optional)
128 libkmod >= 15 (optional)
129 PAM >= 1.1.2 (optional)
130 libcryptsetup (optional)
133 libselinux (optional)
135 liblz4 >= 119 (optional)
137 libqrencode (optional)
138 libmicrohttpd (optional)
141 elfutils >= 158 (optional)
142 make, gcc, and similar tools
144 During runtime, you need the following additional
147 util-linux >= v2.27.1 required
148 dbus >= 1.4.0 (strictly speaking optional, but recommended)
149 NOTE: If using dbus < 1.9.18, you should override the default
150 policy directory (--with-dbuspolicydir=/etc/dbus-1/system.d).
154 When building from git, the following tools are needed:
165 python-lxml (optional, but required to build the indices)
167 The build system is initialized with ./autogen.sh. A tar ball
169 git archive --format=tar --prefix=systemd-222/ v222 | xz > systemd-222.tar.xz
171 When systemd-hostnamed is used, it is strongly recommended to
172 install nss-myhostname to ensure that, in a world of
173 dynamically changing hostnames, the hostname stays resolvable
174 under all circumstances. In fact, systemd-hostnamed will warn
175 if nss-myhostname is not installed.
177 Additional packages are necessary to run some tests:
178 - busybox (used by test/TEST-13-NSPAWN-SMOKE)
179 - nc (used by test/TEST-12-ISSUE-3171)
181 - python3-evdev (used by hwdb parsing tests)
182 - strace (used by test/test-functions)
185 Default udev rules use the following standard system group
186 names, which need to be resolvable by getgrnam() at any time,
187 even in the very early boot stages, where no other databases
188 and network are available:
190 audio, cdrom, dialout, disk, input, kmem, lp, tape, tty, video
192 During runtime, the journal daemon requires the
193 "systemd-journal" system group to exist. New journal files will
194 be readable by this group (but not writable), which may be used
195 to grant specific users read access. In addition, system
196 groups "wheel" and "adm" will be given read-only access to
197 journal files using systemd-tmpfiles.service.
199 The journal gateway daemon requires the
200 "systemd-journal-gateway" system user and group to
201 exist. During execution this network facing service will drop
202 privileges and assume this uid/gid for security reasons.
204 Similarly, the NTP daemon requires the "systemd-timesync" system
205 user and group to exist.
207 Similarly, the network management daemon requires the
208 "systemd-network" system user and group to exist.
210 Similarly, the name resolution daemon requires the
211 "systemd-resolve" system user and group to exist.
213 Similarly, the coredump support requires the
214 "systemd-coredump" system user and group to exist.
217 systemd ships with four glibc NSS modules:
219 nss-myhostname resolves the local hostname to locally
220 configured IP addresses, as well as "localhost" to
223 nss-resolve enables DNS resolution via the systemd-resolved
224 DNS/LLMNR caching stub resolver "systemd-resolved".
226 nss-mymachines enables resolution of all local containers registered
227 with machined to their respective IP addresses. It also maps UID/GIDs
228 ranges used by containers to useful names.
230 nss-systemd enables resolution of all dynamically allocated service
231 users. (See the DynamicUser= setting in unit files.)
233 To make use of these NSS modules, please add them to the "hosts:",
234 "passwd:" and "group:" lines in /etc/nsswitch.conf. The "resolve"
235 module should replace the glibc "dns" module in this file (and don't
236 worry, it chain-loads the "dns" module if it can't talk to resolved).
238 The four modules should be used in the following order:
240 passwd: compat mymachines systemd
241 group: compat mymachines systemd
242 hosts: files mymachines resolve myhostname
245 When calling "systemctl enable/disable/is-enabled" on a unit which is a
246 SysV init.d script, it calls /usr/lib/systemd/systemd-sysv-install;
247 this needs to translate the action into the distribution specific
248 mechanism such as chkconfig or update-rc.d. Packagers need to provide
249 this script if you need this functionality (you don't if you disabled
252 Please see src/systemctl/systemd-sysv-install.SKELETON for how this
253 needs to look like, and provide an implementation at the marked places.
256 systemd will warn you during boot if /usr is on a different
257 file system than /. While in systemd itself very little will
258 break if /usr is on a separate partition, many of its
259 dependencies very likely will break sooner or later in one
260 form or another. For example, udev rules tend to refer to
261 binaries in /usr, binaries that link to libraries in /usr or
262 binaries that refer to data files in /usr. Since these
263 breakages are not always directly visible, systemd will warn
264 about this, since this kind of file system setup is not really
265 supported anymore by the basic set of Linux OS components.
267 systemd requires that the /run mount point exists. systemd also
268 requires that /var/run is a symlink to /run.
270 For more information on this issue consult
271 http://freedesktop.org/wiki/Software/systemd/separate-usr-is-broken
273 To run systemd under valgrind, compile with VALGRIND defined
274 (e.g. ./configure CPPFLAGS='... -DVALGRIND=1'). Otherwise,
275 false positives will be triggered by code which violates
276 some rules but is actually safe.
278 Currently, systemd-timesyncd defaults to use the Google NTP
279 servers if not specified otherwise at configure time. You
280 really should not ship an OS or device with this default
281 setting. See DISTRO_PORTING for details.
283 ENGINEERING AND CONSULTING SERVICES:
284 Kinvolk (https://kinvolk.io) offers professional engineering
285 and consulting services for systemd. Please contact Chris Kühl
286 <chris@kinvolk.io> for more information.