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d657c51f | 1 | systemd System and Service Manager |
31cee6f6 LP |
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: | |
eb0914fc JB |
10 | git@github.com:systemd/systemd.git |
11 | https://github.com/systemd/systemd.git | |
31cee6f6 LP |
12 | |
13 | GITWEB: | |
eb0914fc | 14 | https://github.com/systemd/systemd |
31cee6f6 LP |
15 | |
16 | MAILING LIST: | |
17 | http://lists.freedesktop.org/mailman/listinfo/systemd-devel | |
31cee6f6 LP |
18 | |
19 | IRC: | |
20 | #systemd on irc.freenode.org | |
21 | ||
22 | BUG REPORTS: | |
eb0914fc | 23 | https://github.com/systemd/systemd/issues |
31cee6f6 LP |
24 | |
25 | AUTHOR: | |
5430f7f2 LP |
26 | Lennart Poettering |
27 | Kay Sievers | |
28 | ...and many others | |
31cee6f6 | 29 | |
673eab9b | 30 | LICENSE: |
5430f7f2 | 31 | LGPLv2.1+ for all code |
a095315b KS |
32 | - except src/basic/MurmurHash2.c which is Public Domain |
33 | - except src/basic/siphash24.c which is CC0 Public Domain | |
85424725 KS |
34 | - except src/journal/lookup3.c which is Public Domain |
35 | - except src/udev/* which is (currently still) GPLv2, GPLv2+ | |
673eab9b | 36 | |
31cee6f6 | 37 | REQUIREMENTS: |
58015d78 | 38 | Linux kernel >= 3.12 |
a0c3e16b | 39 | Linux kernel >= 4.2 for unified cgroup hierarchy support |
23aedd02 KS |
40 | |
41 | Kernel Config Options: | |
713bc0cf | 42 | CONFIG_DEVTMPFS |
d28315e4 | 43 | CONFIG_CGROUPS (it is OK to disable all controllers) |
713bc0cf KS |
44 | CONFIG_INOTIFY_USER |
45 | CONFIG_SIGNALFD | |
46 | CONFIG_TIMERFD | |
47 | CONFIG_EPOLL | |
41938693 | 48 | CONFIG_NET |
713bc0cf | 49 | CONFIG_SYSFS |
06d461ee | 50 | CONFIG_PROC_FS |
5d31974e | 51 | CONFIG_FHANDLE (libudev, mount and bind mount handling) |
713bc0cf | 52 | |
be2ea723 | 53 | udev will fail to work with the legacy sysfs layout: |
f28cbd03 | 54 | CONFIG_SYSFS_DEPRECATED=n |
713bc0cf KS |
55 | |
56 | Legacy hotplug slows down the system and confuses udev: | |
57 | CONFIG_UEVENT_HELPER_PATH="" | |
58 | ||
be2ea723 KS |
59 | Userspace firmware loading is not supported and should |
60 | be disabled in the kernel: | |
713bc0cf KS |
61 | CONFIG_FW_LOADER_USER_HELPER=n |
62 | ||
63 | Some udev rules and virtualization detection relies on it: | |
64 | CONFIG_DMIID | |
65 | ||
a5c724b2 KS |
66 | Support for some SCSI devices serial number retrieval, to |
67 | create additional symlinks in /dev/disk/ and /dev/tape: | |
68 | CONFIG_BLK_DEV_BSG | |
69 | ||
b52a4a3b | 70 | Required for PrivateNetwork and PrivateDevices in service units: |
13468826 | 71 | CONFIG_NET_NS |
b52a4a3b ZJS |
72 | CONFIG_DEVPTS_MULTIPLE_INSTANCES |
73 | Note that systemd-localed.service and other systemd units use | |
74 | PrivateNetwork and PrivateDevices so this is effectively required. | |
13468826 | 75 | |
713bc0cf KS |
76 | Optional but strongly recommended: |
77 | CONFIG_IPV6 | |
78 | CONFIG_AUTOFS4_FS | |
713bc0cf | 79 | CONFIG_TMPFS_XATTR |
a6cccd8f | 80 | CONFIG_{TMPFS,EXT4,XFS,BTRFS_FS,...}_POSIX_ACL |
f28cbd03 | 81 | CONFIG_SECCOMP |
3b920d78 | 82 | CONFIG_CHECKPOINT_RESTORE (for the kcmp() syscall) |
713bc0cf | 83 | |
f4e74be1 | 84 | Required for CPUShares= in resource control unit settings |
a21b4670 UTL |
85 | CONFIG_CGROUP_SCHED |
86 | CONFIG_FAIR_GROUP_SCHED | |
87 | ||
f4e74be1 | 88 | Required for CPUQuota= in resource control unit settings |
0acd5a08 WC |
89 | CONFIG_CFS_BANDWIDTH |
90 | ||
f28cbd03 | 91 | For UEFI systems: |
f33016ff | 92 | CONFIG_EFIVAR_FS |
f28cbd03 KS |
93 | CONFIG_EFI_PARTITION |
94 | ||
f4e74be1 LP |
95 | We recommend to turn off Real-Time group scheduling in the |
96 | kernel when using systemd. RT group scheduling effectively | |
97 | makes RT scheduling unavailable for most userspace, since it | |
98 | requires explicit assignment of RT budgets to each unit whose | |
99 | processes making use of RT. As there's no sensible way to | |
100 | assign these budgets automatically this cannot really be | |
101 | fixed, and it's best to disable group scheduling hence. | |
102 | CONFIG_RT_GROUP_SCHED=n | |
103 | ||
77b6e194 LP |
104 | Note that kernel auditing is broken when used with systemd's |
105 | container code. When using systemd in conjunction with | |
19aadacf | 106 | containers, please make sure to either turn off auditing at |
77b6e194 LP |
107 | runtime using the kernel command line option "audit=0", or |
108 | turn it off at kernel compile time using: | |
109 | CONFIG_AUDIT=n | |
a7b1c397 LP |
110 | If systemd is compiled with libseccomp support on |
111 | architectures which do not use socketcall() and where seccomp | |
112 | is supported (this effectively means x86-64 and ARM, but | |
70a44afe | 113 | excludes 32-bit x86!), then nspawn will now install a |
a7b1c397 LP |
114 | work-around seccomp filter that makes containers boot even |
115 | with audit being enabled. This works correctly only on kernels | |
116 | 3.14 and newer though. TL;DR: turn audit off, still. | |
77b6e194 | 117 | |
3dd26f3e | 118 | glibc >= 2.16 |
3ede835a | 119 | libcap |
1d40ddbf | 120 | libmount >= 2.27.1 (from util-linux) |
d5bd92bb | 121 | (util-linux *must* be built with --enable-libmount-force-mountinfo) |
c0467cf3 | 122 | libseccomp >= 1.0.0 (optional) |
d47f6ca5 | 123 | libblkid >= 2.24 (from util-linux) (optional) |
a18535d9 | 124 | libkmod >= 15 (optional) |
3ede835a LP |
125 | PAM >= 1.1.2 (optional) |
126 | libcryptsetup (optional) | |
127 | libaudit (optional) | |
19d5d4cb | 128 | libacl (optional) |
3ede835a | 129 | libselinux (optional) |
19d5d4cb | 130 | liblzma (optional) |
a509e0e6 | 131 | liblz4 >= 119 (optional) |
7b17a7d7 LP |
132 | libgcrypt (optional) |
133 | libqrencode (optional) | |
134 | libmicrohttpd (optional) | |
2cc86f09 | 135 | libpython (optional) |
f9ffbca2 | 136 | libidn (optional) |
5b244719 | 137 | elfutils >= 158 (optional) |
2cc86f09 ZJS |
138 | make, gcc, and similar tools |
139 | ||
19aadacf JE |
140 | During runtime, you need the following additional |
141 | dependencies: | |
2cc86f09 | 142 | |
1d40ddbf | 143 | util-linux >= v2.27.1 required |
df41776d | 144 | dbus >= 1.4.0 (strictly speaking optional, but recommended) |
2cc86f09 | 145 | dracut (optional) |
46ba8aae | 146 | PolicyKit (optional) |
3ede835a | 147 | |
82627069 | 148 | When building from git, the following tools are needed: |
3ede835a | 149 | |
f4e5354a | 150 | pkg-config |
3ede835a LP |
151 | docbook-xsl |
152 | xsltproc | |
153 | automake | |
154 | autoconf | |
155 | libtool | |
19d5d4cb | 156 | intltool |
b62cfcea | 157 | gperf |
19d5d4cb | 158 | python (optional) |
32dcef3a | 159 | python-lxml (optional, but required to build the indices) |
21bc923a | 160 | |
82627069 KS |
161 | The build system is initialized with ./autogen.sh. A tar ball |
162 | can be created with: | |
163 | git archive --format=tar --prefix=systemd-222/ v222 | xz > systemd-222.tar.xz | |
164 | ||
19aadacf JE |
165 | When systemd-hostnamed is used, it is strongly recommended to |
166 | install nss-myhostname to ensure that, in a world of | |
167 | dynamically changing hostnames, the hostname stays resolvable | |
fff2e5b5 | 168 | under all circumstances. In fact, systemd-hostnamed will warn |
bf9e477c | 169 | if nss-myhostname is not installed. |
fff2e5b5 | 170 | |
a24c64f0 | 171 | USERS AND GROUPS: |
37495eed LP |
172 | Default udev rules use the following standard system group |
173 | names, which need to be resolvable by getgrnam() at any time, | |
174 | even in the very early boot stages, where no other databases | |
175 | and network are available: | |
176 | ||
3dff3e00 | 177 | audio, cdrom, dialout, disk, input, kmem, lp, tape, tty, video |
37c0e8f3 | 178 | |
19aadacf | 179 | During runtime, the journal daemon requires the |
1a9ce3f7 | 180 | "systemd-journal" system group to exist. New journal files will |
19aadacf | 181 | be readable by this group (but not writable), which may be used |
a48a62a1 ZJS |
182 | to grant specific users read access. In addition, system |
183 | groups "wheel" and "adm" will be given read-only access to | |
184 | journal files using systemd-tmpfiles.service. | |
a24c64f0 | 185 | |
37495eed | 186 | The journal gateway daemon requires the |
1a9ce3f7 | 187 | "systemd-journal-gateway" system user and group to |
37495eed LP |
188 | exist. During execution this network facing service will drop |
189 | privileges and assume this uid/gid for security reasons. | |
190 | ||
8d0e0ddd | 191 | Similarly, the NTP daemon requires the "systemd-timesync" system |
323a2f0b LP |
192 | user and group to exist. |
193 | ||
8d0e0ddd | 194 | Similarly, the network management daemon requires the |
323a2f0b LP |
195 | "systemd-network" system user and group to exist. |
196 | ||
8d0e0ddd | 197 | Similarly, the name resolution daemon requires the |
323a2f0b LP |
198 | "systemd-resolve" system user and group to exist. |
199 | ||
888e378d LP |
200 | Similarly, the coredump support requires the |
201 | "systemd-coredump" system user and group to exist. | |
202 | ||
a4a79605 LP |
203 | NSS: |
204 | systemd ships with three NSS modules: | |
205 | ||
206 | nss-myhostname resolves the local hostname to locally | |
207 | configured IP addresses, as well as "localhost" to | |
208 | 127.0.0.1/::1. | |
209 | ||
210 | nss-resolve enables DNS resolution via the systemd-resolved | |
211 | DNS/LLMNR caching stub resolver "systemd-resolved". | |
212 | ||
213 | nss-mymachines enables resolution of all local containers | |
214 | registered with machined to their respective IP addresses. | |
215 | ||
216 | To make use of these NSS modules, please add them to the | |
217 | "hosts: " line in /etc/nsswitch.conf. The "resolve" module | |
218 | should replace the glibc "dns" module in this file. | |
219 | ||
220 | The three modules should be used in the following order: | |
221 | ||
222 | hosts: files mymachines resolve myhostname | |
223 | ||
0f0467e6 MP |
224 | SYSV INIT.D SCRIPTS: |
225 | When calling "systemctl enable/disable/is-enabled" on a unit which is a | |
226 | SysV init.d script, it calls /usr/lib/systemd/systemd-sysv-install; | |
227 | this needs to translate the action into the distribution specific | |
228 | mechanism such as chkconfig or update-rc.d. Packagers need to provide | |
229 | this script if you need this functionality (you don't if you disabled | |
230 | SysV init support). | |
231 | ||
232 | Please see src/systemctl/systemd-sysv-install.SKELETON for how this | |
233 | needs to look like, and provide an implementation at the marked places. | |
234 | ||
21bc923a | 235 | WARNINGS: |
21bc923a LP |
236 | systemd will warn you during boot if /usr is on a different |
237 | file system than /. While in systemd itself very little will | |
19aadacf | 238 | break if /usr is on a separate partition, many of its |
21bc923a | 239 | dependencies very likely will break sooner or later in one |
19aadacf | 240 | form or another. For example, udev rules tend to refer to |
21bc923a LP |
241 | binaries in /usr, binaries that link to libraries in /usr or |
242 | binaries that refer to data files in /usr. Since these | |
19aadacf | 243 | breakages are not always directly visible, systemd will warn |
21bc923a LP |
244 | about this, since this kind of file system setup is not really |
245 | supported anymore by the basic set of Linux OS components. | |
fc7a744c | 246 | |
47bc23c1 | 247 | systemd requires that the /run mount point exists. systemd also |
8f42ccd2 | 248 | requires that /var/run is a symlink to /run. |
47bc23c1 | 249 | |
aa167132 LP |
250 | For more information on this issue consult |
251 | http://freedesktop.org/wiki/Software/systemd/separate-usr-is-broken | |
252 | ||
1b4bb4fd ZJS |
253 | To run systemd under valgrind, compile with VALGRIND defined |
254 | (e.g. ./configure CPPFLAGS='... -DVALGRIND=1'). Otherwise, | |
255 | false positives will be triggered by code which violates | |
256 | some rules but is actually safe. | |
2b671e95 | 257 | |
2ed3de9c LP |
258 | Currently, systemd-timesyncd defaults to use the Google NTP |
259 | servers if not specified otherwise at configure time. You | |
260 | really should not ship an OS or device with this default | |
261 | setting. See DISTRO_PORTING for details. | |
ada64a0c LP |
262 | |
263 | ENGINEERING AND CONSULTING SERVICES: | |
264 | Kinvolk (https://kinvolk.io) offers professional engineering | |
265 | and consulting services for systemd. Please contact Chris Kühl | |
266 | <chris@kinvolk.io> for more information. |