summaryrefslogtreecommitdiff
path: root/README
blob: a0ee4878abc07616bc39f2ccc7b8afdedeb0e034 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
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
        http://lists.freedesktop.org/mailman/listinfo/systemd-commits

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/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+

REQUIREMENTS:
        Linux kernel >= 3.7
        Linux kernel >= 3.8 for Smack 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 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 >= 2.16
        libcap
        libmount >= 2.20 (from util-linux)
        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)
        gobject-introspection > 1.40.0 (optional)
        elfutils >= 158 (optional)
        make, gcc, and similar tools

        During runtime, you need the following additional
        dependencies:

        util-linux >= v2.26 required
        dbus >= 1.4.0 (strictly speaking optional, but recommended)
        dracut (optional)
        PolicyKit (optional)

        When building from git, you need the following additional
        dependencies:

        pkg-config
        docbook-xsl
        xsltproc
        automake
        autoconf
        libtool
        intltool
        gperf
        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-<target>', with <target>
        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. 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 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

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 /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 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.

ENGINEERING AND CONSULTING SERVICES:
        ENDOCODE <https://endocode.com/> offers professional
        engineering and consulting services for systemd. Please
        contact Chris Kühl <chris@endocode.com> for more information.