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_SECCOMP_FILTER (required for seccomp support)
83 CONFIG_CHECKPOINT_RESTORE (for the kcmp() syscall)
85 Required for CPUShares= in resource control unit settings
87 CONFIG_FAIR_GROUP_SCHED
89 Required for CPUQuota= in resource control unit settings
96 We recommend to turn off Real-Time group scheduling in the
97 kernel when using systemd. RT group scheduling effectively
98 makes RT scheduling unavailable for most userspace, since it
99 requires explicit assignment of RT budgets to each unit whose
100 processes making use of RT. As there's no sensible way to
101 assign these budgets automatically this cannot really be
102 fixed, and it's best to disable group scheduling hence.
103 CONFIG_RT_GROUP_SCHED=n
105 Note that kernel auditing is broken when used with systemd's
106 container code. When using systemd in conjunction with
107 containers, please make sure to either turn off auditing at
108 runtime using the kernel command line option "audit=0", or
109 turn it off at kernel compile time using:
111 If systemd is compiled with libseccomp support on
112 architectures which do not use socketcall() and where seccomp
113 is supported (this effectively means x86-64 and ARM, but
114 excludes 32-bit x86!), then nspawn will now install a
115 work-around seccomp filter that makes containers boot even
116 with audit being enabled. This works correctly only on kernels
117 3.14 and newer though. TL;DR: turn audit off, still.
121 libmount >= 2.27.1 (from util-linux)
122 (util-linux *must* be built with --enable-libmount-force-mountinfo)
123 libseccomp >= 2.3.1 (optional)
124 libblkid >= 2.24 (from util-linux) (optional)
125 libkmod >= 15 (optional)
126 PAM >= 1.1.2 (optional)
127 libcryptsetup (optional)
130 libselinux (optional)
132 liblz4 >= 119 (optional)
134 libqrencode (optional)
135 libmicrohttpd (optional)
138 elfutils >= 158 (optional)
139 make, gcc, and similar tools
141 During runtime, you need the following additional
144 util-linux >= v2.27.1 required
145 dbus >= 1.4.0 (strictly speaking optional, but recommended)
146 NOTE: If using dbus < 1.9.18, you should override the default
147 policy directory (--with-dbuspolicydir=/etc/dbus-1/system.d).
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.
174 Additional packages are necessary to run some tests:
175 - busybox (used by test/TEST-13-NSPAWN-SMOKE)
176 - nc (used by test/TEST-12-ISSUE-3171)
178 - python3-evdev (used by hwdb parsing tests)
179 - strace (used by test/test-functions)
182 Default udev rules use the following standard system group
183 names, which need to be resolvable by getgrnam() at any time,
184 even in the very early boot stages, where no other databases
185 and network are available:
187 audio, cdrom, dialout, disk, input, kmem, lp, tape, tty, video
189 During runtime, the journal daemon requires the
190 "systemd-journal" system group to exist. New journal files will
191 be readable by this group (but not writable), which may be used
192 to grant specific users read access. In addition, system
193 groups "wheel" and "adm" will be given read-only access to
194 journal files using systemd-tmpfiles.service.
196 The journal gateway daemon requires the
197 "systemd-journal-gateway" system user and group to
198 exist. During execution this network facing service will drop
199 privileges and assume this uid/gid for security reasons.
201 Similarly, the NTP daemon requires the "systemd-timesync" system
202 user and group to exist.
204 Similarly, the network management daemon requires the
205 "systemd-network" system user and group to exist.
207 Similarly, the name resolution daemon requires the
208 "systemd-resolve" system user and group to exist.
210 Similarly, the coredump support requires the
211 "systemd-coredump" system user and group to exist.
214 systemd ships with four glibc NSS modules:
216 nss-myhostname resolves the local hostname to locally
217 configured IP addresses, as well as "localhost" to
220 nss-resolve enables DNS resolution via the systemd-resolved
221 DNS/LLMNR caching stub resolver "systemd-resolved".
223 nss-mymachines enables resolution of all local containers registered
224 with machined to their respective IP addresses. It also maps UID/GIDs
225 ranges used by containers to useful names.
227 nss-systemd enables resolution of all dynamically allocated service
228 users. (See the DynamicUser= setting in unit files.)
230 To make use of these NSS modules, please add them to the "hosts:",
231 "passwd:" and "group:" lines in /etc/nsswitch.conf. The "resolve"
232 module should replace the glibc "dns" module in this file (and don't
233 worry, it chain-loads the "dns" module if it can't talk to resolved).
235 The four modules should be used in the following order:
237 passwd: compat mymachines systemd
238 group: compat mymachines systemd
239 hosts: files mymachines resolve myhostname
242 When calling "systemctl enable/disable/is-enabled" on a unit which is a
243 SysV init.d script, it calls /usr/lib/systemd/systemd-sysv-install;
244 this needs to translate the action into the distribution specific
245 mechanism such as chkconfig or update-rc.d. Packagers need to provide
246 this script if you need this functionality (you don't if you disabled
249 Please see src/systemctl/systemd-sysv-install.SKELETON for how this
250 needs to look like, and provide an implementation at the marked places.
253 systemd will warn you during boot if /usr is on a different
254 file system than /. While in systemd itself very little will
255 break if /usr is on a separate partition, many of its
256 dependencies very likely will break sooner or later in one
257 form or another. For example, udev rules tend to refer to
258 binaries in /usr, binaries that link to libraries in /usr or
259 binaries that refer to data files in /usr. Since these
260 breakages are not always directly visible, systemd will warn
261 about this, since this kind of file system setup is not really
262 supported anymore by the basic set of Linux OS components.
264 systemd requires that the /run mount point exists. systemd also
265 requires that /var/run is a symlink to /run.
267 For more information on this issue consult
268 http://freedesktop.org/wiki/Software/systemd/separate-usr-is-broken
270 To run systemd under valgrind, compile with VALGRIND defined
271 (e.g. ./configure CPPFLAGS='... -DVALGRIND=1'). Otherwise,
272 false positives will be triggered by code which violates
273 some rules but is actually safe.
275 Currently, systemd-timesyncd defaults to use the Google NTP
276 servers if not specified otherwise at configure time. You
277 really should not ship an OS or device with this default
278 setting. See DISTRO_PORTING for details.
280 ENGINEERING AND CONSULTING SERVICES:
281 Kinvolk (https://kinvolk.io) offers professional engineering
282 and consulting services for systemd. Please contact Chris Kühl
283 <chris@kinvolk.io> for more information.