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 machined ID if it is missing or
empty. The new machine ID will be acquired in the following fashion:
1. 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.
2. If run inside a KVM virtual machine and a UUID is was 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
3. 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 ContainerInterface.
4. 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:
Takes a directory path as argument. All paths operated will be
prefixed with the given alternate root path, including the path
for /etc/machine-id itself.
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
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
This command is primarily used by the
systemd-machine-id-commit.service(8) early boot service.
Print the machine ID generated or commited after the operation is
Print a short help text and exit.
Print a short version string and exit.
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report for this manual page, see
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systemd 231 SYSTEMD-MACHINE-ID-SETUP(1)