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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EXIT STATUS | SEE ALSO | NOTES | COLOPHON |
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SYSTEMD-M...-ID-SETUP(1) systemd-machine-id-setupSYSTEMD-M...-ID-SETUP(1)
systemd-machine-id-setup - Initialize the machine ID in
/etc/machine-id
systemd-machine-id-setup
systemd-machine-id-setup may be used by system installer tools to
initialize the machine ID stored in /etc/machine-id at install
time, with a provisioned or randomly generated ID. See
machine-id(5) for more information about this file.
If the tool is invoked without the --commit switch,
/etc/machine-id is initialized with a valid, new machine ID if it
is missing or empty. The new machine ID will be acquired in the
following fashion:
1. If a valid machine ID is stored in /run/machine-id, the
machine ID is copied and used to initialize the machine ID in
/etc/machine-id. This step is skipped if --root= is specified
or running in a chroot environment.
2. If a valid D-Bus machine ID is already configured for the
system, the D-Bus machine ID is copied and used to initialize
the machine ID in /etc/machine-id.
3. If a valid machine ID is provided through system.machine_id
credential, the machine ID is copied and used to initialize
the machine ID in /etc/machine-id. This step is skipped if
--root= is specified or running in a chroot environment.
4. If run inside a KVM virtual machine and a UUID is configured
(via the -uuid option), this UUID is used to initialize the
machine ID. The caller must ensure that the UUID passed is
sufficiently unique and is different for every booted instance
of the VM. This step is skipped if --root= is specified or
running in a chroot environment.
5. Similarly, if run inside a Linux container environment and a
UUID is configured for the container, this is used to
initialize the machine ID. For details, see the documentation
of the Container Interface[1]. This step is skipped if --root=
is specified or running in a chroot environment.
6. Otherwise, a new ID is randomly generated.
The --commit switch may be used to commit a transient machined ID
to disk, making it persistent. For details, see below.
Use systemd-firstboot(1) to initialize the machine ID on mounted
(but not booted) system images.
The following options are understood:
--root=path
Takes a directory path as argument. All paths operated on will
be prefixed with the given alternate root path, including the
path for /etc/machine-id itself.
Added in version 212.
--image=path
Takes a path to a device node or regular file as argument.
This is similar to --root= as described above, but operates on
a disk image instead of a directory tree.
Added in version 249.
--image-policy=policy
Takes an image policy string as argument, as per
systemd.image-policy(7). The policy is enforced when operating
on the disk image specified via --image=, see above. If not
specified, defaults to the "*" policy, i.e. all recognized
file systems in the image are used.
--commit
Commit a transient machine ID to disk. This command may be
used to convert a transient machine ID into a persistent one.
A transient machine ID file is one that was bind mounted from
a memory file system (usually "tmpfs") to /etc/machine-id
during the early phase of the boot process. This may happen
because /etc/ is initially read-only and was missing a valid
machine ID file at that point.
This command will execute no operation if /etc/machine-id is
not mounted from a memory file system, or if /etc/ is
read-only. The command will write the current transient
machine ID to disk and unmount the /etc/machine-id mount point
in a race-free manner to ensure that this file is always valid
and accessible for other processes.
This command is primarily used by the
systemd-machine-id-commit.service(8) early boot service.
Added in version 227.
--print
Print the machine ID generated or committed after the
operation is complete.
Added in version 231.
-h, --help
Print a short help text and exit.
--version
Print a short version string and exit.
On success, 0 is returned, a non-zero failure code otherwise.
systemd(1), machine-id(5), systemd-machine-id-commit.service(8),
dbus-uuidgen(1), systemd-firstboot(1)
1. Container Interface
https://systemd.io/CONTAINER_INTERFACE
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 2025-08-11. (At that
time, the date of the most recent commit that was found in the
repository was 2025-08-11.) 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 258~rc2 SYSTEMD-M...-ID-SETUP(1)
Pages that refer to this page: systemd-firstboot(1), machine-id(5), systemd.directives(7), systemd.index(7), systemd-machine-id-commit.service(8)
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HTML rendering created 2025-09-06 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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