mirror of
https://github.com/systemd/systemd.git
synced 2024-11-27 12:13:33 +08:00
267 lines
10 KiB
Plaintext
267 lines
10 KiB
Plaintext
systemd System and Service Manager
|
|
|
|
DETAILS:
|
|
http://0pointer.de/blog/projects/systemd.html
|
|
|
|
WEB SITE:
|
|
http://www.freedesktop.org/wiki/Software/systemd
|
|
|
|
GIT:
|
|
git@github.com:systemd/systemd.git
|
|
https://github.com/systemd/systemd.git
|
|
|
|
GITWEB:
|
|
https://github.com/systemd/systemd
|
|
|
|
MAILING LIST:
|
|
http://lists.freedesktop.org/mailman/listinfo/systemd-devel
|
|
|
|
IRC:
|
|
#systemd on irc.freenode.org
|
|
|
|
BUG REPORTS:
|
|
https://github.com/systemd/systemd/issues
|
|
|
|
AUTHOR:
|
|
Lennart Poettering
|
|
Kay Sievers
|
|
...and many others
|
|
|
|
LICENSE:
|
|
LGPLv2.1+ for all code
|
|
- except src/basic/MurmurHash2.c which is Public Domain
|
|
- except src/basic/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+
|
|
|
|
REQUIREMENTS:
|
|
Linux kernel >= 3.12
|
|
Linux kernel >= 4.2 for unified cgroup hierarchy support
|
|
|
|
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)
|
|
|
|
udev will fail to work with the legacy sysfs layout:
|
|
CONFIG_SYSFS_DEPRECATED=n
|
|
|
|
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 and PrivateDevices in service units:
|
|
CONFIG_NET_NS
|
|
CONFIG_DEVPTS_MULTIPLE_INSTANCES
|
|
Note that systemd-localed.service and other systemd units use
|
|
PrivateNetwork and PrivateDevices so this is effectively required.
|
|
|
|
Optional but strongly recommended:
|
|
CONFIG_IPV6
|
|
CONFIG_AUTOFS4_FS
|
|
CONFIG_TMPFS_XATTR
|
|
CONFIG_{TMPFS,EXT4,XFS,BTRFS_FS,...}_POSIX_ACL
|
|
CONFIG_SECCOMP
|
|
CONFIG_CHECKPOINT_RESTORE (for the kcmp() syscall)
|
|
|
|
Required for CPUShares= in resource control unit settings
|
|
CONFIG_CGROUP_SCHED
|
|
CONFIG_FAIR_GROUP_SCHED
|
|
|
|
Required for CPUQuota= in resource control unit settings
|
|
CONFIG_CFS_BANDWIDTH
|
|
|
|
For UEFI systems:
|
|
CONFIG_EFIVAR_FS
|
|
CONFIG_EFI_PARTITION
|
|
|
|
We recommend to turn off Real-Time group scheduling in the
|
|
kernel when using systemd. RT group scheduling effectively
|
|
makes RT scheduling unavailable for most userspace, since it
|
|
requires explicit assignment of RT budgets to each unit whose
|
|
processes making use of RT. As there's no sensible way to
|
|
assign these budgets automatically this cannot really be
|
|
fixed, and it's best to disable group scheduling hence.
|
|
CONFIG_RT_GROUP_SCHED=n
|
|
|
|
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 >= 2.16
|
|
libcap
|
|
libmount >= 2.27.1 (from util-linux)
|
|
(util-linux *must* be built with --enable-libmount-force-mountinfo)
|
|
libseccomp >= 1.0.0 (optional)
|
|
libblkid >= 2.24 (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)
|
|
elfutils >= 158 (optional)
|
|
make, gcc, and similar tools
|
|
|
|
During runtime, you need the following additional
|
|
dependencies:
|
|
|
|
util-linux >= v2.27.1 required
|
|
dbus >= 1.4.0 (strictly speaking optional, but recommended)
|
|
dracut (optional)
|
|
PolicyKit (optional)
|
|
|
|
When building from git, the following tools are needed:
|
|
|
|
pkg-config
|
|
docbook-xsl
|
|
xsltproc
|
|
automake
|
|
autoconf
|
|
libtool
|
|
intltool
|
|
gperf
|
|
python (optional)
|
|
python-lxml (optional, but required to build the indices)
|
|
|
|
The build system is initialized with ./autogen.sh. A tar ball
|
|
can be created with:
|
|
git archive --format=tar --prefix=systemd-222/ v222 | xz > systemd-222.tar.xz
|
|
|
|
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.
|
|
|
|
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. In addition, system
|
|
groups "wheel" and "adm" will be given read-only access to
|
|
journal files using systemd-tmpfiles.service.
|
|
|
|
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 coredump support requires the
|
|
"systemd-coredump" 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
|
|
|
|
SYSV INIT.D SCRIPTS:
|
|
When calling "systemctl enable/disable/is-enabled" on a unit which is a
|
|
SysV init.d script, it calls /usr/lib/systemd/systemd-sysv-install;
|
|
this needs to translate the action into the distribution specific
|
|
mechanism such as chkconfig or update-rc.d. Packagers need to provide
|
|
this script if you need this functionality (you don't if you disabled
|
|
SysV init support).
|
|
|
|
Please see src/systemctl/systemd-sysv-install.SKELETON for how this
|
|
needs to look like, and provide an implementation at the marked places.
|
|
|
|
WARNINGS:
|
|
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 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.
|
|
|
|
Currently, systemd-timesyncd defaults to use the Google NTP
|
|
servers if not specified otherwise at configure time. You
|
|
really should not ship an OS or device with this default
|
|
setting. See DISTRO_PORTING for details.
|
|
|
|
ENGINEERING AND CONSULTING SERVICES:
|
|
Kinvolk (https://kinvolk.io) offers professional engineering
|
|
and consulting services for systemd. Please contact Chris Kühl
|
|
<chris@kinvolk.io> for more information.
|