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NAME | SYNOPSIS | DESCRIPTION | EXAMPLES | SEE ALSO | NOTES | COLOPHON |
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CAPSULE@.SERVICE(5) capsule@.service CAPSULE@.SERVICE(5)
capsule@.service - System unit for the capsule service manager
capsule@NAME.service
Service managers for capsules run in capsule@NAME.service system
units, with the capsule name as the instance identifier. Capsules
are way to run additional instances of the service manager, under
dynamic user IDs, i.e. UIDs that are allocated when the capsule
service manager is started, and released when it is stopped.
In many ways capsule@.service is similar to the per-user
user@.service service manager, but there are a few important
distinctions:
• The capsule service manager utilizes DynamicUser= (see
systemd.exec(5)) to allocate a new UID dynamically on
invocation. The user name is automatically generated from the
capsule name, by prefixng "p_". The UID is released when the
service is terminated. The user service manager on the other
hand operates under a statically allocated user ID that must
be pre-existing, before the user service manager is invoked.
• User service managers register themselves with pam(8),
capsule service managers do not.
• User service managers typically read their configuration from
a $HOME directory below /home/, capsule service managers from
a $HOME directory below /var/lib/capsules/.
• User service managers are collectively contained in the
user.slice unit, capsule service managers in capsule.slice.
Also see systemd.special(7).
• User service managers start the user unit default.target
initially. Capsule service managers invoke the user unit
capsule@.target instead.
The capsule service manager and the capsule's bus broker can be
reached via the --capsule= switch to systemctl(1), systemd-run(1)
and busctl(1).
New capsules can be started via a simple systemctl start
capsule@NAME.service command, and stopped via systemctl stop
capsule@NAME.service. Starting a capsule will implicitly create a
home directory /var/lib/capsules/NAME/, if missing. A runtime
directory is created as /run/capsules/NAME/. To remove these
resources use systemctl clean capsule@NAME.service, for example
with the --what=all switch.
The capsule@.service unit invokes a systemd --user service
manager process. This means unit files are looked for according
to the sames rules as for regular user service managers, for
example in /var/lib/capsules/NAME/.config/systemd/user/.
Capsule names may be chosen freely by the user, however, they
must be suitable as UNIX filenames (i.e. 255 characters max, and
contain no "/"), and when prefixed with "p-" be suitable as a
user name matching strict POSIX rules, see User/Group Name
Syntax[1] for details.
Added in version 256.
Example 1. Create a new capsule, invoke two programs in it (one
interactively), terminate it, and clean everything up
# systemctl start capsule@tatze.service
# systemd-run --capsule=tatze --unit=sleeptest.service sleep 999
# systemctl --capsule=tatze status sleeptest.service
# systemd-run -t --capsule=tatze bash
# systemctl --capsule=tatze stop sleeptest.service
# systemctl stop capsule@tatze.service
# systemctl clean --all capsule@tatze.service
systemd(1), user@.service(5), systemd.service(5),
systemd.slice(5), systemd.exec(5), systemd.special(7),
systemctl(1), systemd-run(1), busctl(1), pam(8)
1. User/Group Name Syntax
https://systemd.io/USER_NAMES
This page is part of the systemd (systemd system and service
manager) project. Information about the project can be found at
⟨http://www.freedesktop.org/wiki/Software/systemd⟩. If you have
a bug report for this manual page, see
⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩.
This page was obtained from the project's upstream Git repository
⟨https://github.com/systemd/systemd.git⟩ on 2024-06-14. (At that
time, the date of the most recent commit that was found in the
repository was 2024-06-13.) If you discover any rendering
problems in this HTML version of the page, or you believe there
is a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
systemd 257~devel CAPSULE@.SERVICE(5)
Pages that refer to this page: busctl(1), systemctl(1), systemd-run(1), user@.service(5), systemd.directives(7), systemd.index(7), systemd.special(7)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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