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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: | |
19d9372b | 7 | https://www.freedesktop.org/wiki/Software/systemd |
31cee6f6 LP |
8 | |
9 | GIT: | |
eb0914fc | 10 | git@github.com:systemd/systemd.git |
eb0914fc | 11 | https://github.com/systemd/systemd |
31cee6f6 LP |
12 | |
13 | MAILING LIST: | |
19d9372b | 14 | https://lists.freedesktop.org/mailman/listinfo/systemd-devel |
31cee6f6 LP |
15 | |
16 | IRC: | |
17 | #systemd on irc.freenode.org | |
18 | ||
19 | BUG REPORTS: | |
eb0914fc | 20 | https://github.com/systemd/systemd/issues |
31cee6f6 LP |
21 | |
22 | AUTHOR: | |
5430f7f2 LP |
23 | Lennart Poettering |
24 | Kay Sievers | |
25 | ...and many others | |
31cee6f6 | 26 | |
673eab9b | 27 | LICENSE: |
5430f7f2 | 28 | LGPLv2.1+ for all code |
a095315b KS |
29 | - except src/basic/MurmurHash2.c which is Public Domain |
30 | - except src/basic/siphash24.c which is CC0 Public Domain | |
85424725 KS |
31 | - except src/journal/lookup3.c which is Public Domain |
32 | - except src/udev/* which is (currently still) GPLv2, GPLv2+ | |
673eab9b | 33 | |
31cee6f6 | 34 | REQUIREMENTS: |
dcce98a4 | 35 | Linux kernel >= 3.13 |
a0c3e16b | 36 | Linux kernel >= 4.2 for unified cgroup hierarchy support |
23aedd02 KS |
37 | |
38 | Kernel Config Options: | |
713bc0cf | 39 | CONFIG_DEVTMPFS |
d28315e4 | 40 | CONFIG_CGROUPS (it is OK to disable all controllers) |
713bc0cf KS |
41 | CONFIG_INOTIFY_USER |
42 | CONFIG_SIGNALFD | |
43 | CONFIG_TIMERFD | |
44 | CONFIG_EPOLL | |
41938693 | 45 | CONFIG_NET |
713bc0cf | 46 | CONFIG_SYSFS |
06d461ee | 47 | CONFIG_PROC_FS |
5d31974e | 48 | CONFIG_FHANDLE (libudev, mount and bind mount handling) |
713bc0cf | 49 | |
9c7f7d86 MG |
50 | Kernel crypto/hash API |
51 | CONFIG_CRYPTO_USER_API_HASH | |
52 | CONFIG_CRYPTO_HMAC | |
53 | CONFIG_CRYPTO_SHA256 | |
54 | ||
be2ea723 | 55 | udev will fail to work with the legacy sysfs layout: |
f28cbd03 | 56 | CONFIG_SYSFS_DEPRECATED=n |
713bc0cf KS |
57 | |
58 | Legacy hotplug slows down the system and confuses udev: | |
59 | CONFIG_UEVENT_HELPER_PATH="" | |
60 | ||
be2ea723 KS |
61 | Userspace firmware loading is not supported and should |
62 | be disabled in the kernel: | |
713bc0cf KS |
63 | CONFIG_FW_LOADER_USER_HELPER=n |
64 | ||
65 | Some udev rules and virtualization detection relies on it: | |
66 | CONFIG_DMIID | |
67 | ||
a5c724b2 KS |
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 | ||
0ca48bb0 | 72 | Required for PrivateNetwork= and PrivateDevices= in service units: |
13468826 | 73 | CONFIG_NET_NS |
b52a4a3b ZJS |
74 | CONFIG_DEVPTS_MULTIPLE_INSTANCES |
75 | Note that systemd-localed.service and other systemd units use | |
76 | PrivateNetwork and PrivateDevices so this is effectively required. | |
13468826 | 77 | |
0ca48bb0 | 78 | Required for PrivateUsers= in service units: |
87fe1707 LW |
79 | CONFIG_USER_NS |
80 | ||
713bc0cf KS |
81 | Optional but strongly recommended: |
82 | CONFIG_IPV6 | |
83 | CONFIG_AUTOFS4_FS | |
713bc0cf | 84 | CONFIG_TMPFS_XATTR |
a6cccd8f | 85 | CONFIG_{TMPFS,EXT4,XFS,BTRFS_FS,...}_POSIX_ACL |
f28cbd03 | 86 | CONFIG_SECCOMP |
fd74fa79 | 87 | CONFIG_SECCOMP_FILTER (required for seccomp support) |
3b920d78 | 88 | CONFIG_CHECKPOINT_RESTORE (for the kcmp() syscall) |
713bc0cf | 89 | |
f4e74be1 | 90 | Required for CPUShares= in resource control unit settings |
a21b4670 UTL |
91 | CONFIG_CGROUP_SCHED |
92 | CONFIG_FAIR_GROUP_SCHED | |
93 | ||
f4e74be1 | 94 | Required for CPUQuota= in resource control unit settings |
0acd5a08 WC |
95 | CONFIG_CFS_BANDWIDTH |
96 | ||
f28cbd03 | 97 | For UEFI systems: |
f33016ff | 98 | CONFIG_EFIVAR_FS |
f28cbd03 KS |
99 | CONFIG_EFI_PARTITION |
100 | ||
f4e74be1 LP |
101 | We recommend to turn off Real-Time group scheduling in the |
102 | kernel when using systemd. RT group scheduling effectively | |
103 | makes RT scheduling unavailable for most userspace, since it | |
104 | requires explicit assignment of RT budgets to each unit whose | |
105 | processes making use of RT. As there's no sensible way to | |
106 | assign these budgets automatically this cannot really be | |
107 | fixed, and it's best to disable group scheduling hence. | |
108 | CONFIG_RT_GROUP_SCHED=n | |
109 | ||
f5a93d5d LP |
110 | It's a good idea to disable the implicit creation of networking bonding |
111 | devices by the kernel networking bonding module, so that the | |
112 | automatically created "bond0" interface doesn't conflict with any such | |
582faeb4 DJL |
113 | device created by systemd-networkd (or other tools). Ideally there |
114 | would be a kernel compile-time option for this, but there currently | |
115 | isn't. The next best thing is to make this change through a modprobe.d | |
116 | drop-in. This is shipped by default, see modprobe.d/systemd.conf. | |
f5a93d5d | 117 | |
77b6e194 LP |
118 | Note that kernel auditing is broken when used with systemd's |
119 | container code. When using systemd in conjunction with | |
19aadacf | 120 | containers, please make sure to either turn off auditing at |
77b6e194 LP |
121 | runtime using the kernel command line option "audit=0", or |
122 | turn it off at kernel compile time using: | |
123 | CONFIG_AUDIT=n | |
a7b1c397 LP |
124 | If systemd is compiled with libseccomp support on |
125 | architectures which do not use socketcall() and where seccomp | |
126 | is supported (this effectively means x86-64 and ARM, but | |
70a44afe | 127 | excludes 32-bit x86!), then nspawn will now install a |
a7b1c397 LP |
128 | work-around seccomp filter that makes containers boot even |
129 | with audit being enabled. This works correctly only on kernels | |
130 | 3.14 and newer though. TL;DR: turn audit off, still. | |
77b6e194 | 131 | |
3dd26f3e | 132 | glibc >= 2.16 |
3ede835a | 133 | libcap |
d6e80966 ZJS |
134 | libmount >= 2.30 (from util-linux) |
135 | (util-linux *must* be built without --enable-libmount-support-mtab) | |
6abfd303 | 136 | libseccomp >= 2.3.1 (optional) |
d47f6ca5 | 137 | libblkid >= 2.24 (from util-linux) (optional) |
a18535d9 | 138 | libkmod >= 15 (optional) |
3ede835a LP |
139 | PAM >= 1.1.2 (optional) |
140 | libcryptsetup (optional) | |
141 | libaudit (optional) | |
19d5d4cb | 142 | libacl (optional) |
3ede835a | 143 | libselinux (optional) |
19d5d4cb | 144 | liblzma (optional) |
a509e0e6 | 145 | liblz4 >= 119 (optional) |
7b17a7d7 LP |
146 | libgcrypt (optional) |
147 | libqrencode (optional) | |
148 | libmicrohttpd (optional) | |
2cc86f09 | 149 | libpython (optional) |
87057e24 | 150 | libidn2 or libidn (optional) |
5b244719 | 151 | elfutils >= 158 (optional) |
d79a2f5f | 152 | polkit (optional) |
72cdb3e7 | 153 | pkg-config |
8f968c73 | 154 | gperf |
72cdb3e7 ZJS |
155 | docbook-xsl (optional, required for documentation) |
156 | xsltproc (optional, required for documentation) | |
157 | python-lxml (optional, required to build the indices) | |
158 | python, meson, ninja | |
159 | gcc, awk, sed, grep, m4, and similar tools | |
2cc86f09 | 160 | |
19aadacf JE |
161 | During runtime, you need the following additional |
162 | dependencies: | |
2cc86f09 | 163 | |
1d40ddbf | 164 | util-linux >= v2.27.1 required |
ecf4f0a8 MG |
165 | dbus >= 1.4.0 (strictly speaking optional, but recommended) |
166 | NOTE: If using dbus < 1.9.18, you should override the default | |
167 | policy directory (--with-dbuspolicydir=/etc/dbus-1/system.d). | |
2cc86f09 | 168 | dracut (optional) |
46ba8aae | 169 | PolicyKit (optional) |
3ede835a | 170 | |
3e609a8a ZJS |
171 | To build in directory build/: |
172 | meson build/ && ninja -C build | |
173 | ||
174 | Any configuration options can be specfied as -Darg=value... arguments | |
175 | to meson. After the build directory is initially configured, meson will | |
176 | refuse to run again, and options must be changed with: | |
177 | mesonconf -Darg=value... | |
178 | mesonconf without any arguments will print out available options and | |
179 | their current values. | |
180 | ||
181 | Useful commands: | |
182 | ninja -v some/target | |
183 | ninja test | |
184 | sudo ninja install | |
185 | DESTDIR=... ninja install | |
186 | ||
72cdb3e7 | 187 | A tarball can be created with: |
82627069 KS |
188 | git archive --format=tar --prefix=systemd-222/ v222 | xz > systemd-222.tar.xz |
189 | ||
19aadacf JE |
190 | When systemd-hostnamed is used, it is strongly recommended to |
191 | install nss-myhostname to ensure that, in a world of | |
192 | dynamically changing hostnames, the hostname stays resolvable | |
fff2e5b5 | 193 | under all circumstances. In fact, systemd-hostnamed will warn |
bf9e477c | 194 | if nss-myhostname is not installed. |
fff2e5b5 | 195 | |
a2fc3d87 ZJS |
196 | Additional packages are necessary to run some tests: |
197 | - busybox (used by test/TEST-13-NSPAWN-SMOKE) | |
198 | - nc (used by test/TEST-12-ISSUE-3171) | |
199 | - python3-pyparsing | |
200 | - python3-evdev (used by hwdb parsing tests) | |
201 | - strace (used by test/test-functions) | |
e94681ad | 202 | - capsh (optional, used by test-execute) |
a2fc3d87 | 203 | |
a24c64f0 | 204 | USERS AND GROUPS: |
37495eed LP |
205 | Default udev rules use the following standard system group |
206 | names, which need to be resolvable by getgrnam() at any time, | |
207 | even in the very early boot stages, where no other databases | |
208 | and network are available: | |
209 | ||
3dff3e00 | 210 | audio, cdrom, dialout, disk, input, kmem, lp, tape, tty, video |
37c0e8f3 | 211 | |
19aadacf | 212 | During runtime, the journal daemon requires the |
1a9ce3f7 | 213 | "systemd-journal" system group to exist. New journal files will |
19aadacf | 214 | be readable by this group (but not writable), which may be used |
a48a62a1 ZJS |
215 | to grant specific users read access. In addition, system |
216 | groups "wheel" and "adm" will be given read-only access to | |
217 | journal files using systemd-tmpfiles.service. | |
a24c64f0 | 218 | |
37495eed | 219 | The journal gateway daemon requires the |
1a9ce3f7 | 220 | "systemd-journal-gateway" system user and group to |
37495eed LP |
221 | exist. During execution this network facing service will drop |
222 | privileges and assume this uid/gid for security reasons. | |
223 | ||
8d0e0ddd | 224 | Similarly, the NTP daemon requires the "systemd-timesync" system |
323a2f0b LP |
225 | user and group to exist. |
226 | ||
8d0e0ddd | 227 | Similarly, the network management daemon requires the |
323a2f0b LP |
228 | "systemd-network" system user and group to exist. |
229 | ||
8d0e0ddd | 230 | Similarly, the name resolution daemon requires the |
323a2f0b LP |
231 | "systemd-resolve" system user and group to exist. |
232 | ||
888e378d LP |
233 | Similarly, the coredump support requires the |
234 | "systemd-coredump" system user and group to exist. | |
235 | ||
a4a79605 | 236 | NSS: |
409093fe | 237 | systemd ships with four glibc NSS modules: |
a4a79605 LP |
238 | |
239 | nss-myhostname resolves the local hostname to locally | |
240 | configured IP addresses, as well as "localhost" to | |
241 | 127.0.0.1/::1. | |
242 | ||
243 | nss-resolve enables DNS resolution via the systemd-resolved | |
244 | DNS/LLMNR caching stub resolver "systemd-resolved". | |
245 | ||
409093fe LP |
246 | nss-mymachines enables resolution of all local containers registered |
247 | with machined to their respective IP addresses. It also maps UID/GIDs | |
248 | ranges used by containers to useful names. | |
a4a79605 | 249 | |
409093fe LP |
250 | nss-systemd enables resolution of all dynamically allocated service |
251 | users. (See the DynamicUser= setting in unit files.) | |
a4a79605 | 252 | |
409093fe LP |
253 | To make use of these NSS modules, please add them to the "hosts:", |
254 | "passwd:" and "group:" lines in /etc/nsswitch.conf. The "resolve" | |
255 | module should replace the glibc "dns" module in this file (and don't | |
256 | worry, it chain-loads the "dns" module if it can't talk to resolved). | |
a4a79605 | 257 | |
409093fe LP |
258 | The four modules should be used in the following order: |
259 | ||
260 | passwd: compat mymachines systemd | |
261 | group: compat mymachines systemd | |
a4a79605 LP |
262 | hosts: files mymachines resolve myhostname |
263 | ||
0f0467e6 MP |
264 | SYSV INIT.D SCRIPTS: |
265 | When calling "systemctl enable/disable/is-enabled" on a unit which is a | |
266 | SysV init.d script, it calls /usr/lib/systemd/systemd-sysv-install; | |
267 | this needs to translate the action into the distribution specific | |
268 | mechanism such as chkconfig or update-rc.d. Packagers need to provide | |
269 | this script if you need this functionality (you don't if you disabled | |
270 | SysV init support). | |
271 | ||
272 | Please see src/systemctl/systemd-sysv-install.SKELETON for how this | |
273 | needs to look like, and provide an implementation at the marked places. | |
274 | ||
21bc923a | 275 | WARNINGS: |
21bc923a LP |
276 | systemd will warn you during boot if /usr is on a different |
277 | file system than /. While in systemd itself very little will | |
19aadacf | 278 | break if /usr is on a separate partition, many of its |
21bc923a | 279 | dependencies very likely will break sooner or later in one |
19aadacf | 280 | form or another. For example, udev rules tend to refer to |
21bc923a LP |
281 | binaries in /usr, binaries that link to libraries in /usr or |
282 | binaries that refer to data files in /usr. Since these | |
19aadacf | 283 | breakages are not always directly visible, systemd will warn |
21bc923a LP |
284 | about this, since this kind of file system setup is not really |
285 | supported anymore by the basic set of Linux OS components. | |
fc7a744c | 286 | |
47bc23c1 | 287 | systemd requires that the /run mount point exists. systemd also |
8f42ccd2 | 288 | requires that /var/run is a symlink to /run. |
47bc23c1 | 289 | |
aa167132 | 290 | For more information on this issue consult |
c6749ba5 | 291 | https://www.freedesktop.org/wiki/Software/systemd/separate-usr-is-broken |
aa167132 | 292 | |
1b4bb4fd | 293 | To run systemd under valgrind, compile with VALGRIND defined |
7817154d MS |
294 | (e.g. CPPFLAGS='... -DVALGRIND=1' meson <options>) and have valgrind |
295 | development headers installed (i.e. valgrind-devel or | |
296 | equivalent). Otherwise, false positives will be triggered by code which | |
297 | violates some rules but is actually safe. Note that valgrind generates | |
298 | nice output only on exit(), hence on shutdown we don't execve() | |
299 | systemd-shutdown. | |
2b671e95 | 300 | |
ada64a0c LP |
301 | ENGINEERING AND CONSULTING SERVICES: |
302 | Kinvolk (https://kinvolk.io) offers professional engineering | |
303 | and consulting services for systemd. Please contact Chris Kühl | |
304 | <chris@kinvolk.io> for more information. |