documentation/dev-manual/init-manager.rst

1 .. SPDX-License-Identifier: CC-BY-SA-2.0-UK
3 .. _init-manager:
8 By default, the Yocto Project uses :wikipedia:`SysVinit <Init#SysV-style>` as
13 features that are used by many distributions.
30 file, with a very similar syntax, though of course BusyBox init features
42 of a given service, though systemd will also provide more services by default,
51 The ":ref:`device-manager`" chapter has more details about device managers.
57 default setting in Poky. This corresponds to setting::
68    INIT_MANAGER = "mdev-busybox"
80 See :yocto_git:`meta/conf/distro/include/init-manager-systemd.inc
81 </poky/tree/meta/conf/distro/include/init-manager-systemd.inc>` for exact
85 -----------------------------------------------
91 -  ``systemctl status``: show the status of all services
92 -  ``systemctl status <service>``: show the status of one service
93 -  ``systemctl [start|stop] <service>``: start or stop a service
94 -  ``systemctl [enable|disable] <service>``: enable or disable a service at boot time
95 -  ``systemctl list-units``: list all available units
96 -  ``journalctl -a``: show all logs for all services
97 -  ``journalctl -f``: show only the last log entries, and keep printing updates as they arrive
98 -  ``journalctl -u``: show only logs from a particular service
100 Using systemd-journald without a traditional syslog daemon
101 ----------------------------------------------------------
103 Counter-intuitively, ``systemd-journald`` is not a syslog runtime or provider,
104 and the proper way to use ``systemd-journald`` as your sole logging mechanism is to
108    VIRTUAL-RUNTIME_syslog = ""
109    VIRTUAL-RUNTIME_base-utils-syslog = ""
111 Doing so will prevent ``rsyslog`` / ``busybox-syslog`` from being pulled in by
112 default, leaving only ``systemd-journald``.
115 -------
120 .. list-table::
122    :header-rows: 1
124    * -
125      - BusyBox init
126      - SysVinit
127      - systemd
128    * - Size
129      - Small
130      - Small
131      - Big [#footnote-systemd-size]_
132    * - Complexity
133      - Small
134      - Medium
135      - High
136    * - Support for boot profiles
137      - No
138      - Yes ("runlevels")
139      - Yes ("targets")
140    * - Services defined as
141      - Shell scripts
142      - Shell scripts
143      - Description files
144    * - Starting services in parallel
145      - No
146      - No
147      - Yes
148    * - Setting service resource limits
149      - No
150      - No
151      - Yes
152    * - Support service isolation
153      - No
154      - No
155      - Yes
156    * - Integrated logging
157      - No
158      - No
159      - Yes
161 .. [#footnote-systemd-size] Using systemd increases the ``core-image-minimal``
162    image size by 160\% for ``qemux86-64`` on Mickledore (4.2), compared to SysVinit.