README

   1 systemd System and Service Manager
   2
   3 DETAILS:
   4         http://0pointer.de/blog/projects/systemd.html
   5
   6 WEB SITE:
   7         http://www.freedesktop.org/wiki/Software/systemd
   8
   9 GIT:
  10         git://anongit.freedesktop.org/systemd/systemd
  11         ssh://git.freedesktop.org/git/systemd/systemd
  12
  13 GITWEB:
  14         http://cgit.freedesktop.org/systemd/systemd
  15
  16 MAILING LIST:
  17         http://lists.freedesktop.org/mailman/listinfo/systemd-devel
  18         http://lists.freedesktop.org/mailman/listinfo/systemd-commits
  19
  20 IRC:
  21         #systemd on irc.freenode.org
  22
  23 BUG REPORTS:
  24         https://bugs.freedesktop.org/enter_bug.cgi?product=systemd
  25
  26 AUTHOR:
  27         Lennart Poettering
  28         Kay Sievers
  29         ...and many others
  30
  31 LICENSE:
  32         LGPLv2.1+ for all code
  33         - except src/shared/MurmurHash2.c which is Public Domain
  34         - except src/shared/siphash24.c which is CC0 Public Domain
  35         - except src/journal/lookup3.c which is Public Domain
  36         - except src/udev/* which is (currently still) GPLv2, GPLv2+
  37
  38 REQUIREMENTS:
  39         Linux kernel >= 3.7
  40         Linux kernel >= 3.8 for Smack support
  41
  42         Kernel Config Options:
  43           CONFIG_DEVTMPFS
  44           CONFIG_CGROUPS (it is OK to disable all controllers)
  45           CONFIG_INOTIFY_USER
  46           CONFIG_SIGNALFD
  47           CONFIG_TIMERFD
  48           CONFIG_EPOLL
  49           CONFIG_NET
  50           CONFIG_SYSFS
  51           CONFIG_PROC_FS
  52           CONFIG_FHANDLE (libudev, mount and bind mount handling)
  53
  54         udev will fail to work with the legacy sysfs layout:
  55           CONFIG_SYSFS_DEPRECATED=n
  56
  57         Legacy hotplug slows down the system and confuses udev:
  58           CONFIG_UEVENT_HELPER_PATH=""
  59
  60         Userspace firmware loading is not supported and should
  61         be disabled in the kernel:
  62           CONFIG_FW_LOADER_USER_HELPER=n
  63
  64         Some udev rules and virtualization detection relies on it:
  65           CONFIG_DMIID
  66
  67         Support for some SCSI devices serial number retrieval, to
  68         create additional symlinks in /dev/disk/ and /dev/tape:
  69           CONFIG_BLK_DEV_BSG
  70
  71         Required for PrivateNetwork and PrivateDevices in service units:
  72           CONFIG_NET_NS
  73           CONFIG_DEVPTS_MULTIPLE_INSTANCES
  74         Note that systemd-localed.service and other systemd units use
  75         PrivateNetwork and PrivateDevices so this is effectively required.
  76
  77         Optional but strongly recommended:
  78           CONFIG_IPV6
  79           CONFIG_AUTOFS4_FS
  80           CONFIG_TMPFS_POSIX_ACL
  81           CONFIG_TMPFS_XATTR
  82           CONFIG_SECCOMP
  83
  84         Required for CPUShares in resource control unit settings
  85           CONFIG_CGROUP_SCHED
  86           CONFIG_FAIR_GROUP_SCHED
  87
  88         Required for CPUQuota in resource control unit settings
  89           CONFIG_CFS_BANDWIDTH
  90
  91         For systemd-bootchart, several proc debug interfaces are required:
  92           CONFIG_SCHEDSTATS
  93           CONFIG_SCHED_DEBUG
  94
  95         For UEFI systems:
  96           CONFIG_EFIVAR_FS
  97           CONFIG_EFI_PARTITION
  98
  99         Note that kernel auditing is broken when used with systemd's
 100         container code. When using systemd in conjunction with
 101         containers, please make sure to either turn off auditing at
 102         runtime using the kernel command line option "audit=0", or
 103         turn it off at kernel compile time using:
 104           CONFIG_AUDIT=n
 105         If systemd is compiled with libseccomp support on
 106         architectures which do not use socketcall() and where seccomp
 107         is supported (this effectively means x86-64 and ARM, but
 108         excludes 32-bit x86!), then nspawn will now install a
 109         work-around seccomp filter that makes containers boot even
 110         with audit being enabled. This works correctly only on kernels
 111         3.14 and newer though. TL;DR: turn audit off, still.
 112
 113         glibc >= 2.14
 114         libcap
 115         libmount >= 2.20 (from util-linux)
 116         libseccomp >= 1.0.0 (optional)
 117         libblkid >= 2.24 (from util-linux) (optional)
 118         libkmod >= 15 (optional)
 119         PAM >= 1.1.2 (optional)
 120         libcryptsetup (optional)
 121         libaudit (optional)
 122         libacl (optional)
 123         libselinux (optional)
 124         liblzma (optional)
 125         liblz4 >= 119 (optional)
 126         libgcrypt (optional)
 127         libqrencode (optional)
 128         libmicrohttpd (optional)
 129         libpython (optional)
 130         libidn (optional)
 131         gobject-introspection > 1.40.0 (optional)
 132         elfutils >= 158 (optional)
 133         make, gcc, and similar tools
 134
 135         During runtime, you need the following additional
 136         dependencies:
 137
 138         util-linux >= v2.25 required
 139         dbus >= 1.4.0 (strictly speaking optional, but recommended)
 140         dracut (optional)
 141         PolicyKit (optional)
 142
 143         When building from git, you need the following additional
 144         dependencies:
 145
 146         docbook-xsl
 147         xsltproc
 148         automake
 149         autoconf
 150         libtool
 151         intltool
 152         gperf
 153         gtkdocize (optional)
 154         python (optional)
 155         python-lxml (optional, but required to build the indices)
 156         sphinx (optional)
 157
 158         When systemd-hostnamed is used, it is strongly recommended to
 159         install nss-myhostname to ensure that, in a world of
 160         dynamically changing hostnames, the hostname stays resolvable
 161         under all circumstances. In fact, systemd-hostnamed will warn
 162         if nss-myhostname is not installed.
 163
 164         To build HTML documentation for python-systemd using sphinx,
 165         please first install systemd (using 'make install'), and then
 166         invoke sphinx-build with 'make sphinx-<target>', with <target>
 167         being 'html' or 'latexpdf'. If using DESTDIR for installation,
 168         pass the same DESTDIR to 'make sphinx-html' invocation.
 169
 170 USERS AND GROUPS:
 171         Default udev rules use the following standard system group
 172         names, which need to be resolvable by getgrnam() at any time,
 173         even in the very early boot stages, where no other databases
 174         and network are available:
 175
 176         audio, cdrom, dialout, disk, input, kmem, lp, tape, tty, video
 177
 178         During runtime, the journal daemon requires the
 179         "systemd-journal" system group to exist. New journal files will
 180         be readable by this group (but not writable), which may be used
 181         to grant specific users read access.
 182
 183         It is also recommended to grant read access to all journal
 184         files to the system groups "wheel" and "adm" with a command
 185         like the following in the post installation script of the
 186         package:
 187
 188         # setfacl -nm g:wheel:rx,d:g:wheel:rx,g:adm:rx,d:g:adm:rx /var/log/journal/
 189
 190         The journal gateway daemon requires the
 191         "systemd-journal-gateway" system user and group to
 192         exist. During execution this network facing service will drop
 193         privileges and assume this uid/gid for security reasons.
 194
 195         Similarly, the NTP daemon requires the "systemd-timesync" system
 196         user and group to exist.
 197
 198         Similarly, the network management daemon requires the
 199         "systemd-network" system user and group to exist.
 200
 201         Similarly, the name resolution daemon requires the
 202         "systemd-resolve" system user and group to exist.
 203
 204         Similarly, the kdbus dbus1 proxy daemon requires the
 205         "systemd-bus-proxy" system user and group to exist.
 206
 207 NSS:
 208         systemd ships with three NSS modules:
 209
 210         nss-myhostname resolves the local hostname to locally
 211         configured IP addresses, as well as "localhost" to
 212         127.0.0.1/::1.
 213
 214         nss-resolve enables DNS resolution via the systemd-resolved
 215         DNS/LLMNR caching stub resolver "systemd-resolved".
 216
 217         nss-mymachines enables resolution of all local containers
 218         registered with machined to their respective IP addresses.
 219
 220         To make use of these NSS modules, please add them to the
 221         "hosts: " line in /etc/nsswitch.conf. The "resolve" module
 222         should replace the glibc "dns" module in this file.
 223
 224         The three modules should be used in the following order:
 225
 226                 hosts: files mymachines resolve myhostname
 227
 228 WARNINGS:
 229         systemd will warn you during boot if /etc/mtab is not a
 230         symlink to /proc/mounts. Please ensure that /etc/mtab is a
 231         proper symlink.
 232
 233         systemd will warn you during boot if /usr is on a different
 234         file system than /. While in systemd itself very little will
 235         break if /usr is on a separate partition, many of its
 236         dependencies very likely will break sooner or later in one
 237         form or another. For example, udev rules tend to refer to
 238         binaries in /usr, binaries that link to libraries in /usr or
 239         binaries that refer to data files in /usr. Since these
 240         breakages are not always directly visible, systemd will warn
 241         about this, since this kind of file system setup is not really
 242         supported anymore by the basic set of Linux OS components.
 243
 244         systemd requires that the /run mount point exists. systemd also
 245         requires that /var/run is a a symlink to /run.
 246
 247         For more information on this issue consult
 248         http://freedesktop.org/wiki/Software/systemd/separate-usr-is-broken
 249
 250         To run systemd under valgrind, compile with VALGRIND defined
 251         (e.g. ./configure CPPFLAGS='... -DVALGRIND=1'). Otherwise,
 252         false positives will be triggered by code which violates
 253         some rules but is actually safe.
 254
 255 ENGINEERING AND CONSULTING SERVICES:
 256         ENDOCODE <https://endocode.com/> offers professional
 257         engineering and consulting services for systemd. Please
 258         contact Chris Kühl <chris@endocode.com> for more information.