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 sd-readahead.[ch] which is MIT
  34         - except src/shared/MurmurHash2.c which is Public Domain
  35         - except src/shared/siphash24.c which is CC0 Public Domain
  36         - except src/journal/lookup3.c which is Public Domain
  37         - except src/udev/* which is (currently still) GPLv2, GPLv2+
  38
  39 REQUIREMENTS:
  40         Linux kernel >= 3.7
  41         Linux kernel >= 3.8 for Smack support
  42
  43         Kernel Config Options:
  44           CONFIG_DEVTMPFS
  45           CONFIG_CGROUPS (it is OK to disable all controllers)
  46           CONFIG_INOTIFY_USER
  47           CONFIG_SIGNALFD
  48           CONFIG_TIMERFD
  49           CONFIG_EPOLL
  50           CONFIG_NET
  51           CONFIG_SYSFS
  52           CONFIG_PROC_FS
  53           CONFIG_FHANDLE (libudev, mount and bind mount handling)
  54
  55         udev will fail to work with the legacy sysfs layout:
  56           CONFIG_SYSFS_DEPRECATED=n
  57
  58         Legacy hotplug slows down the system and confuses udev:
  59           CONFIG_UEVENT_HELPER_PATH=""
  60
  61         Userspace firmware loading is not supported and should
  62         be disabled in the kernel:
  63           CONFIG_FW_LOADER_USER_HELPER=n
  64
  65         Some udev rules and virtualization detection relies on it:
  66           CONFIG_DMIID
  67
  68         Support for some SCSI devices serial number retrieval, to
  69         create additional symlinks in /dev/disk/ and /dev/tape:
  70           CONFIG_BLK_DEV_BSG
  71
  72         Required for PrivateNetwork in service units:
  73           CONFIG_NET_NS
  74
  75         Optional but strongly recommended:
  76           CONFIG_IPV6
  77           CONFIG_AUTOFS4_FS
  78           CONFIG_TMPFS_POSIX_ACL
  79           CONFIG_TMPFS_XATTR
  80           CONFIG_SECCOMP
  81
  82         Required for CPUShares in resource control unit settings
  83           CONFIG_CGROUP_SCHED
  84           CONFIG_FAIR_GROUP_SCHED
  85
  86         For systemd-bootchart, several proc debug interfaces are required:
  87           CONFIG_SCHEDSTATS
  88           CONFIG_SCHED_DEBUG
  89
  90         For UEFI systems:
  91           CONFIG_EFIVAR_FS
  92           CONFIG_EFI_PARTITION
  93
  94         Note that kernel auditing is broken when used with systemd's
  95         container code. When using systemd in conjunction with
  96         containers, please make sure to either turn off auditing at
  97         runtime using the kernel command line option "audit=0", or
  98         turn it off at kernel compile time using:
  99           CONFIG_AUDIT=n
 100         If systemd is compiled with libseccomp support on
 101         architectures which do not use socketcall() and where seccomp
 102         is supported (this effectively means x86-64 and ARM, but
 103         excludes 32-bit x86!), then nspawn will now install a
 104         work-around seccomp filter that makes containers boot even
 105         with audit being enabled. This works correctly only on kernels
 106         3.14 and newer though. TL;DR: turn audit off, still.
 107
 108         glibc >= 2.14
 109         libcap
 110         libseccomp >= 1.0.0 (optional)
 111         libblkid >= 2.20 (from util-linux) (optional)
 112         libkmod >= 15 (optional)
 113         PAM >= 1.1.2 (optional)
 114         libcryptsetup (optional)
 115         libaudit (optional)
 116         libacl (optional)
 117         libselinux (optional)
 118         liblzma (optional)
 119         liblz4 >= 119 (optional)
 120         libgcrypt (optional)
 121         libqrencode (optional)
 122         libmicrohttpd (optional)
 123         libpython (optional)
 124         libidn (optional)
 125         gobject-introspection > 1.40.0 (optional)
 126         elfutils >= 158 (optional)
 127         make, gcc, and similar tools
 128
 129         During runtime, you need the following additional
 130         dependencies:
 131
 132         util-linux >= v2.19 (requires fsck -l, agetty -s),
 133                       v2.21 required for tests in test/
 134         dbus >= 1.4.0 (strictly speaking optional, but recommended)
 135         sulogin (from util-linux >= 2.22 or sysvinit-tools, optional but recommended,
 136                  required for tests in test/)
 137         dracut (optional)
 138         PolicyKit (optional)
 139
 140         When building from git, you need the following additional
 141         dependencies:
 142
 143         docbook-xsl
 144         xsltproc
 145         automake
 146         autoconf
 147         libtool
 148         intltool
 149         gperf
 150         gtkdocize (optional)
 151         python (optional)
 152         python-lxml (optional, but required to build the indices)
 153         sphinx (optional)
 154
 155         When systemd-hostnamed is used, it is strongly recommended to
 156         install nss-myhostname to ensure that, in a world of
 157         dynamically changing hostnames, the hostname stays resolvable
 158         under all circumstances. In fact, systemd-hostnamed will warn
 159         if nss-myhostname is not installed.
 160
 161         To build HTML documentation for python-systemd using sphinx,
 162         please first install systemd (using 'make install'), and then
 163         invoke sphinx-build with 'make sphinx-<target>', with <target>
 164         being 'html' or 'latexpdf'. If using DESTDIR for installation,
 165         pass the same DESTDIR to 'make sphinx-html' invocation.
 166
 167 USERS AND GROUPS:
 168         Default udev rules use the following standard system group
 169         names, which need to be resolvable by getgrnam() at any time,
 170         even in the very early boot stages, where no other databases
 171         and network are available:
 172
 173         audio, cdrom, dialout, disk, input, kmem, lp, tape, tty, video
 174
 175         During runtime, the journal daemon requires the
 176         "systemd-journal" system group to exist. New journal files will
 177         be readable by this group (but not writable), which may be used
 178         to grant specific users read access.
 179
 180         It is also recommended to grant read access to all journal
 181         files to the system groups "wheel" and "adm" with a command
 182         like the following in the post installation script of the
 183         package:
 184
 185         # setfacl -nm g:wheel:rx,d:g:wheel:rx,g:adm:rx,d:g:adm:rx /var/log/journal/
 186
 187         The journal gateway daemon requires the
 188         "systemd-journal-gateway" system user and group to
 189         exist. During execution this network facing service will drop
 190         privileges and assume this uid/gid for security reasons.
 191
 192         Similarly, the NTP daemon requires the "systemd-timesync" system
 193         user and group to exist.
 194
 195         Similarly, the network management daemon requires the
 196         "systemd-network" system user and group to exist.
 197
 198         Similarly, the name resolution daemon requires the
 199         "systemd-resolve" system user and group to exist.
 200
 201         Similarly, the kdbus dbus1 proxy daemon requires the
 202         "systemd-bus-proxy" system user and group to exist.
 203
 204 NSS:
 205         systemd ships with three NSS modules:
 206
 207         nss-myhostname resolves the local hostname to locally
 208         configured IP addresses, as well as "localhost" to
 209         127.0.0.1/::1.
 210
 211         nss-resolve enables DNS resolution via the systemd-resolved
 212         DNS/LLMNR caching stub resolver "systemd-resolved".
 213
 214         nss-mymachines enables resolution of all local containers
 215         registered with machined to their respective IP addresses.
 216
 217         To make use of these NSS modules, please add them to the
 218         "hosts: " line in /etc/nsswitch.conf. The "resolve" module
 219         should replace the glibc "dns" module in this file.
 220
 221         The three modules should be used in the following order:
 222
 223                 hosts: files mymachines resolve myhostname
 224
 225 WARNINGS:
 226         systemd will warn you during boot if /etc/mtab is not a
 227         symlink to /proc/mounts. Please ensure that /etc/mtab is a
 228         proper symlink.
 229
 230         systemd will warn you during boot if /usr is on a different
 231         file system than /. While in systemd itself very little will
 232         break if /usr is on a separate partition, many of its
 233         dependencies very likely will break sooner or later in one
 234         form or another. For example, udev rules tend to refer to
 235         binaries in /usr, binaries that link to libraries in /usr or
 236         binaries that refer to data files in /usr. Since these
 237         breakages are not always directly visible, systemd will warn
 238         about this, since this kind of file system setup is not really
 239         supported anymore by the basic set of Linux OS components.
 240
 241         systemd requires that the /run mount point exists. systemd also
 242         requires that /var/run is a a symlink to /run.
 243
 244         For more information on this issue consult
 245         http://freedesktop.org/wiki/Software/systemd/separate-usr-is-broken
 246
 247         To run systemd under valgrind, compile with VALGRIND defined
 248         (e.g. ./configure CPPFLAGS='... -DVALGRIND=1'). Otherwise,
 249         false positives will be triggered by code which violates
 250         some rules but is actually safe.