X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=README;h=144036717cf78198a0f9d0d9b45a9d3def724e3a;hp=a14e5c0fcff04e40b81ab462d236aa12d99fab8e;hb=fedfcdee6f55c3f183752b7fac4879bf41eed60b;hpb=1e03b754aef576a5cb75f01b1805cdc1f9cc292f diff --git a/README b/README index a14e5c0fc..144036717 100644 --- a/README +++ b/README @@ -1,56 +1,246 @@ -udev - userspace device management +systemd System and Service Manager -For more information see the files in the docs/ directory. +DETAILS: + http://0pointer.de/blog/projects/systemd.html -Important Note: - Integrating udev in the system has complex dependencies and differs from distro - to distro. All major distros depend on udev these days and the system may not - work without a properly installed version. The upstream udev project does not - recommend to replace a distro's udev installation with the upstream version. +WEB SITE: + http://www.freedesktop.org/wiki/Software/systemd -Requirements: - - Version 2.6.25 of the Linux kernel with sysfs, procfs, signalfd, inotify, - unix domain sockets, networking and hotplug enabled. +GIT: + git://anongit.freedesktop.org/systemd/systemd + ssh://git.freedesktop.org/git/systemd/systemd - - For reliable operation, the kernel must not use the CONFIG_SYSFS_DEPRECATED* - option. +GITWEB: + http://cgit.freedesktop.org/systemd/systemd - - Unix domain sockets (CONFIG_UNIX) as a loadable kernel module is not - supported. +MAILING LIST: + http://lists.freedesktop.org/mailman/listinfo/systemd-devel + http://lists.freedesktop.org/mailman/listinfo/systemd-commits - - The proc filesystem must be mounted on /proc/, the sysfs filesystem must - be mounted at /sys/. No other locations are supported by udev. +IRC: + #systemd on irc.freenode.org - - The system must have the following group names resolvable at udev startup: - disk, cdrom, floppy, tape, audio, video, lp, tty, dialout, kmem. - Especially in LDAP setups, it is required, that getgrnam() is able to resolve - these group names with only the rootfs mounted, and while no network is - available. +BUG REPORTS: + https://bugs.freedesktop.org/enter_bug.cgi?product=systemd -Operation: - Udev creates and removes device nodes in /dev/, based on events the kernel - sends out on device discovery or removal. +AUTHOR: + Lennart Poettering + Kay Sievers + ...and many others - - Early in the boot process, the /dev/ directory should get a 'tmpfs' - filesystem mounted, which is maintained by udev. Created nodes or changed - permissions will not survive a reboot, which is intentional. +LICENSE: + LGPLv2.1+ for all code + - except src/shared/MurmurHash2.c which is Public Domain + - except src/shared/siphash24.c which is CC0 Public Domain + - except src/journal/lookup3.c which is Public Domain + - except src/udev/* which is (currently still) GPLv2, GPLv2+ - - The content of /lib/udev/devices/ directory which contains the nodes, - symlinks and directories, which are always expected to be in /dev, should - be copied over to the tmpfs mounted /dev, to provide the required nodes - to initialize udev and continue booting. +REQUIREMENTS: + Linux kernel >= 3.7 + Linux kernel >= 3.8 for Smack support - - The old hotplug helper /sbin/hotplug should be disabled in the kernel - configuration, it is not needed, and may render the system unusable - because of a fork-bombing behavior. + Kernel Config Options: + CONFIG_DEVTMPFS + CONFIG_CGROUPS (it is OK to disable all controllers) + CONFIG_INOTIFY_USER + CONFIG_SIGNALFD + CONFIG_TIMERFD + CONFIG_EPOLL + CONFIG_NET + CONFIG_SYSFS + CONFIG_PROC_FS + CONFIG_FHANDLE (libudev, mount and bind mount handling) - - All kernel events are matched against a set of specified rules in - /lib/udev/rules.d/ which make it possible to hook into the event - processing to load required kernel modules and setup devices. For all - devices the kernel exports a major/minor number, udev will create a - device node with the default kernel name, or the one specified by a - matching udev rule. + udev will fail to work with the legacy sysfs layout: + CONFIG_SYSFS_DEPRECATED=n -Please direct any comment/question/concern to the linux-hotplug mailing list at: - linux-hotplug@vger.kernel.org + Legacy hotplug slows down the system and confuses udev: + CONFIG_UEVENT_HELPER_PATH="" + Userspace firmware loading is not supported and should + be disabled in the kernel: + CONFIG_FW_LOADER_USER_HELPER=n + + Some udev rules and virtualization detection relies on it: + CONFIG_DMIID + + Support for some SCSI devices serial number retrieval, to + create additional symlinks in /dev/disk/ and /dev/tape: + CONFIG_BLK_DEV_BSG + + Required for PrivateNetwork in service units: + CONFIG_NET_NS + + Optional but strongly recommended: + CONFIG_IPV6 + CONFIG_AUTOFS4_FS + CONFIG_TMPFS_POSIX_ACL + CONFIG_TMPFS_XATTR + CONFIG_SECCOMP + + Required for CPUShares in resource control unit settings + CONFIG_CGROUP_SCHED + CONFIG_FAIR_GROUP_SCHED + + For systemd-bootchart, several proc debug interfaces are required: + CONFIG_SCHEDSTATS + CONFIG_SCHED_DEBUG + + For UEFI systems: + CONFIG_EFIVAR_FS + CONFIG_EFI_PARTITION + + Note that kernel auditing is broken when used with systemd's + container code. When using systemd in conjunction with + containers, please make sure to either turn off auditing at + runtime using the kernel command line option "audit=0", or + turn it off at kernel compile time using: + CONFIG_AUDIT=n + If systemd is compiled with libseccomp support on + architectures which do not use socketcall() and where seccomp + is supported (this effectively means x86-64 and ARM, but + excludes 32-bit x86!), then nspawn will now install a + work-around seccomp filter that makes containers boot even + with audit being enabled. This works correctly only on kernels + 3.14 and newer though. TL;DR: turn audit off, still. + + glibc >= 2.14 + libcap + libseccomp >= 1.0.0 (optional) + libblkid >= 2.20 (from util-linux) (optional) + libkmod >= 15 (optional) + PAM >= 1.1.2 (optional) + libcryptsetup (optional) + libaudit (optional) + libacl (optional) + libselinux (optional) + liblzma (optional) + liblz4 >= 119 (optional) + libgcrypt (optional) + libqrencode (optional) + libmicrohttpd (optional) + libpython (optional) + libidn (optional) + gobject-introspection > 1.40.0 (optional) + elfutils >= 158 (optional) + make, gcc, and similar tools + + During runtime, you need the following additional + dependencies: + + util-linux >= v2.25 required + dbus >= 1.4.0 (strictly speaking optional, but recommended) + dracut (optional) + PolicyKit (optional) + + When building from git, you need the following additional + dependencies: + + docbook-xsl + xsltproc + automake + autoconf + libtool + intltool + gperf + gtkdocize (optional) + python (optional) + python-lxml (optional, but required to build the indices) + sphinx (optional) + + When systemd-hostnamed is used, it is strongly recommended to + install nss-myhostname to ensure that, in a world of + dynamically changing hostnames, the hostname stays resolvable + under all circumstances. In fact, systemd-hostnamed will warn + if nss-myhostname is not installed. + + To build HTML documentation for python-systemd using sphinx, + please first install systemd (using 'make install'), and then + invoke sphinx-build with 'make sphinx-', with + being 'html' or 'latexpdf'. If using DESTDIR for installation, + pass the same DESTDIR to 'make sphinx-html' invocation. + +USERS AND GROUPS: + Default udev rules use the following standard system group + names, which need to be resolvable by getgrnam() at any time, + even in the very early boot stages, where no other databases + and network are available: + + audio, cdrom, dialout, disk, input, kmem, lp, tape, tty, video + + During runtime, the journal daemon requires the + "systemd-journal" system group to exist. New journal files will + be readable by this group (but not writable), which may be used + to grant specific users read access. + + It is also recommended to grant read access to all journal + files to the system groups "wheel" and "adm" with a command + like the following in the post installation script of the + package: + + # setfacl -nm g:wheel:rx,d:g:wheel:rx,g:adm:rx,d:g:adm:rx /var/log/journal/ + + The journal gateway daemon requires the + "systemd-journal-gateway" system user and group to + exist. During execution this network facing service will drop + privileges and assume this uid/gid for security reasons. + + Similarly, the NTP daemon requires the "systemd-timesync" system + user and group to exist. + + Similarly, the network management daemon requires the + "systemd-network" system user and group to exist. + + Similarly, the name resolution daemon requires the + "systemd-resolve" system user and group to exist. + + Similarly, the kdbus dbus1 proxy daemon requires the + "systemd-bus-proxy" system user and group to exist. + +NSS: + systemd ships with three NSS modules: + + nss-myhostname resolves the local hostname to locally + configured IP addresses, as well as "localhost" to + 127.0.0.1/::1. + + nss-resolve enables DNS resolution via the systemd-resolved + DNS/LLMNR caching stub resolver "systemd-resolved". + + nss-mymachines enables resolution of all local containers + registered with machined to their respective IP addresses. + + To make use of these NSS modules, please add them to the + "hosts: " line in /etc/nsswitch.conf. The "resolve" module + should replace the glibc "dns" module in this file. + + The three modules should be used in the following order: + + hosts: files mymachines resolve myhostname + +WARNINGS: + systemd will warn you during boot if /etc/mtab is not a + symlink to /proc/mounts. Please ensure that /etc/mtab is a + proper symlink. + + systemd will warn you during boot if /usr is on a different + file system than /. While in systemd itself very little will + break if /usr is on a separate partition, many of its + dependencies very likely will break sooner or later in one + form or another. For example, udev rules tend to refer to + binaries in /usr, binaries that link to libraries in /usr or + binaries that refer to data files in /usr. Since these + breakages are not always directly visible, systemd will warn + about this, since this kind of file system setup is not really + supported anymore by the basic set of Linux OS components. + + systemd requires that the /run mount point exists. systemd also + requires that /var/run is a a symlink to /run. + + For more information on this issue consult + http://freedesktop.org/wiki/Software/systemd/separate-usr-is-broken + + To run systemd under valgrind, compile with VALGRIND defined + (e.g. ./configure CPPFLAGS='... -DVALGRIND=1'). Otherwise, + false positives will be triggered by code which violates + some rules but is actually safe.