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SYSTEMD-....SERVICE(8) systemd-machined.service SYSTEMD-....SERVICE(8)
systemd-machined.service, systemd-machined - Virtual machine and
container registration manager
systemd-machined.service
/usr/lib/systemd/systemd-machined
systemd-machined is a system service that keeps track of locally
running virtual machines and containers.
systemd-machined is useful for registering and keeping track of
both OS containers (containers that share the host kernel but run
a full init system of their own and behave in most regards like a
full virtual operating system rather than just one virtualized
app) and full virtual machines (virtualized hardware running
normal operating systems and possibly different kernels).
systemd-machined should not be used for registering/keeping track
of application sandbox containers. A machine in the context of
systemd-machined is supposed to be an abstract term covering both
OS containers and full virtual machines, but not application
sandboxes.
Machines registered with machined are exposed in various ways in
the system. For example:
• Tools like ps(1) will show to which machine a specific
process belongs in a column of its own, and so will
gnome-system-monitor[1] or systemd-cgls(1).
• systemd's various tools (systemctl(1), journalctl(1),
loginctl(1), hostnamectl(1), timedatectl(1), localectl(1),
machinectl(1), ...) support the -M switch to operate on local
containers instead of the host system.
• systemctl list-machines will show the system state of all
local containers, connecting to the container's init system
for that.
• systemctl's --recursive switch has the effect of not only
showing the locally running services, but recursively showing
the services of all registered containers.
• The machinectl command provides access to a number of useful
operations on registered containers, such as introspecting
them, rebooting, shutting them down, and getting a login
prompt on them.
• The sd-bus(3) library exposes the
sd_bus_open_system_machine(3) call to connect to the system
bus of any registered container.
• The nss-mymachines(8) module makes sure all registered
containers can be resolved via normal glibc gethostbyname(3)
or getaddrinfo(3) calls.
See systemd-nspawn(1) for some examples on how to run containers
with OS tools.
If you are interested in writing a VM or container manager that
makes use of machined, please have look at Writing Virtual
Machine or Container Managers[2]. Also see the New Control Group
Interfaces[3].
The daemon provides both a C library interface (which is shared
with systemd-logind.service(8)) as well as a D-Bus interface and
a Varlink interface. The library interface may be used to
introspect and watch the state of virtual machines/containers.
The bus interface provides the same but in addition may also be
used to register or terminate machines. The Varlink interface may
be used to register machines with optional extensions, e.g. with
an SSH key / address; it can be queried with varlinkctl
introspect /run/systemd/machine/io.systemd.Machine
io.systemd.Machine. For more information please consult
sd-login(3) and org.freedesktop.machine1(5) and
org.freedesktop.LogControl1(5).
A small companion daemon systemd-importd.service(8) is also
available, which implements importing, exporting, and downloading
of container and VM images.
For each container registered with systemd-machined.service that
employs user namespacing, users/groups are synthesized for the
used UIDs/GIDs. These are made available to the system using the
User/Group Record Lookup API via Varlink[4], and thus may be
resolved with userdbctl(1) or the usual glibc NSS calls.
systemd(1), machinectl(1), systemd-nspawn(1), nss-mymachines(8),
systemd.special(7)
1. gnome-system-monitor
https://help.gnome.org/users/gnome-system-monitor/
2. Writing Virtual Machine or Container Managers
https://systemd.io/WRITING_VM_AND_CONTAINER_MANAGERS
3. New Control Group Interfaces
https://systemd.io/CONTROL_GROUP_INTERFACE
4. User/Group Record Lookup API via Varlink
https://systemd.io/USER_GROUP_API
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
[email protected]
systemd 257~devel SYSTEMD-....SERVICE(8)
Pages that refer to this page: busctl(1), machinectl(1), systemd-nspawn(1), systemd-vmspawn(1), userdbctl(1), sd_bus_default(3), sd_bus_set_address(3), sd_machine_get_class(3), sd_pid_get_owner_uid(3), org.freedesktop.import1(5), org.freedesktop.machine1(5), systemd.slice(5), systemd.directives(7), systemd.index(7), nss-mymachines(8), nss-systemd(8), systemd-importd.service(8)
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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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