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 in service units:
  72           CONFIG_NET_NS
  73
  74         Optional but strongly recommended:
  75           CONFIG_IPV6
  76           CONFIG_AUTOFS4_FS
  77           CONFIG_TMPFS_POSIX_ACL
  78           CONFIG_TMPFS_XATTR
  79           CONFIG_SECCOMP
  80
  81         Required for CPUShares in resource control unit settings
  82           CONFIG_CGROUP_SCHED
  83           CONFIG_FAIR_GROUP_SCHED
  84
  85         For systemd-bootchart, several proc debug interfaces are required:
  86           CONFIG_SCHEDSTATS
  87           CONFIG_SCHED_DEBUG
  88
  89         For UEFI systems:
  90           CONFIG_EFIVAR_FS
  91           CONFIG_EFI_PARTITION
  92
  93         Note that kernel auditing is broken when used with systemd's
  94         container code. When using systemd in conjunction with
  95         containers, please make sure to either turn off auditing at
  96         runtime using the kernel command line option "audit=0", or
  97         turn it off at kernel compile time using:
  98           CONFIG_AUDIT=n
  99         If systemd is compiled with libseccomp support on
 100         architectures which do not use socketcall() and where seccomp
 101         is supported (this effectively means x86-64 and ARM, but
 102         excludes 32-bit x86!), then nspawn will now install a
 103         work-around seccomp filter that makes containers boot even
 104         with audit being enabled. This works correctly only on kernels
 105         3.14 and newer though. TL;DR: turn audit off, still.
 106
 107         glibc >= 2.14
 108         libcap
 109         libseccomp >= 1.0.0 (optional)
 110         libblkid >= 2.20 (from util-linux) (optional)
 111         libkmod >= 15 (optional)
 112         PAM >= 1.1.2 (optional)
 113         libcryptsetup (optional)
 114         libaudit (optional)
 115         libacl (optional)
 116         libselinux (optional)
 117         liblzma (optional)
 118         liblz4 >= 119 (optional)
 119         libgcrypt (optional)
 120         libqrencode (optional)
 121         libmicrohttpd (optional)
 122         libpython (optional)
 123         libidn (optional)
 124         gobject-introspection > 1.40.0 (optional)
 125         elfutils >= 158 (optional)
 126         make, gcc, and similar tools
 127
 128         During runtime, you need the following additional
 129         dependencies:
 130
 131         util-linux >= v2.25 required
 132         dbus >= 1.4.0 (strictly speaking optional, but recommended)
 133         dracut (optional)
 134         PolicyKit (optional)
 135
 136         When building from git, you need the following additional
 137         dependencies:
 138
 139         docbook-xsl
 140         xsltproc
 141         automake
 142         autoconf
 143         libtool
 144         intltool
 145         gperf
 146         gtkdocize (optional)
 147         python (optional)
 148         python-lxml (optional, but required to build the indices)
 149         sphinx (optional)
 150
 151         When systemd-hostnamed is used, it is strongly recommended to
 152         install nss-myhostname to ensure that, in a world of
 153         dynamically changing hostnames, the hostname stays resolvable
 154         under all circumstances. In fact, systemd-hostnamed will warn
 155         if nss-myhostname is not installed.
 156
 157         To build HTML documentation for python-systemd using sphinx,
 158         please first install systemd (using 'make install'), and then
 159         invoke sphinx-build with 'make sphinx-<target>', with <target>
 160         being 'html' or 'latexpdf'. If using DESTDIR for installation,
 161         pass the same DESTDIR to 'make sphinx-html' invocation.
 162
 163 USERS AND GROUPS:
 164         Default udev rules use the following standard system group
 165         names, which need to be resolvable by getgrnam() at any time,
 166         even in the very early boot stages, where no other databases
 167         and network are available:
 168
 169         audio, cdrom, dialout, disk, input, kmem, lp, tape, tty, video
 170
 171         During runtime, the journal daemon requires the
 172         "systemd-journal" system group to exist. New journal files will
 173         be readable by this group (but not writable), which may be used
 174         to grant specific users read access.
 175
 176         It is also recommended to grant read access to all journal
 177         files to the system groups "wheel" and "adm" with a command
 178         like the following in the post installation script of the
 179         package:
 180
 181         # setfacl -nm g:wheel:rx,d:g:wheel:rx,g:adm:rx,d:g:adm:rx /var/log/journal/
 182
 183         The journal gateway daemon requires the
 184         "systemd-journal-gateway" system user and group to
 185         exist. During execution this network facing service will drop
 186         privileges and assume this uid/gid for security reasons.
 187
 188         Similarly, the NTP daemon requires the "systemd-timesync" system
 189         user and group to exist.
 190
 191         Similarly, the network management daemon requires the
 192         "systemd-network" system user and group to exist.
 193
 194         Similarly, the name resolution daemon requires the
 195         "systemd-resolve" system user and group to exist.
 196
 197         Similarly, the kdbus dbus1 proxy daemon requires the
 198         "systemd-bus-proxy" system user and group to exist.
 199
 200 NSS:
 201         systemd ships with three NSS modules:
 202
 203         nss-myhostname resolves the local hostname to locally
 204         configured IP addresses, as well as "localhost" to
 205         127.0.0.1/::1.
 206
 207         nss-resolve enables DNS resolution via the systemd-resolved
 208         DNS/LLMNR caching stub resolver "systemd-resolved".
 209
 210         nss-mymachines enables resolution of all local containers
 211         registered with machined to their respective IP addresses.
 212
 213         To make use of these NSS modules, please add them to the
 214         "hosts: " line in /etc/nsswitch.conf. The "resolve" module
 215         should replace the glibc "dns" module in this file.
 216
 217         The three modules should be used in the following order:
 218
 219                 hosts: files mymachines resolve myhostname
 220
 221 WARNINGS:
 222         systemd will warn you during boot if /etc/mtab is not a
 223         symlink to /proc/mounts. Please ensure that /etc/mtab is a
 224         proper symlink.
 225
 226         systemd will warn you during boot if /usr is on a different
 227         file system than /. While in systemd itself very little will
 228         break if /usr is on a separate partition, many of its
 229         dependencies very likely will break sooner or later in one
 230         form or another. For example, udev rules tend to refer to
 231         binaries in /usr, binaries that link to libraries in /usr or
 232         binaries that refer to data files in /usr. Since these
 233         breakages are not always directly visible, systemd will warn
 234         about this, since this kind of file system setup is not really
 235         supported anymore by the basic set of Linux OS components.
 236
 237         systemd requires that the /run mount point exists. systemd also
 238         requires that /var/run is a a symlink to /run.
 239
 240         For more information on this issue consult
 241         http://freedesktop.org/wiki/Software/systemd/separate-usr-is-broken
 242
 243         To run systemd under valgrind, compile with VALGRIND defined
 244         (e.g. ./configure CPPFLAGS='... -DVALGRIND=1'). Otherwise,
 245         false positives will be triggered by code which violates
 246         some rules but is actually safe.
 247
 248 ENGINEERING AND CONSULTING SERVICES:
 249         ENDOCODE <https://endocode.com/> offers professional
 250         engineering and consulting services for systemd. Please
 251         contact Chris Kühl <chris@endocode.com> for more information.