systemd-machine-id-setup — Initialize the machine ID in /etc/machine-id
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
for more information about this file.
If the tool is invoked without the
/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:
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
If run inside a KVM virtual machine and a UUID
is configured (via the
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
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.
Otherwise, a new ID is randomly generated.
--commit switch may be used to commit a
transient machined ID to disk, making it persistent. For details,
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 on will be prefixed with the
root path, including the path for
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
Takes an image policy string as argument, as per
policy is enforced when operating on the disk image specified via
above. If not specified defaults to the "
*" policy, i.e. all recognized file systems
in the image are used.
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
/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
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.
Print the machine ID generated or committed after the operation is complete.
On success, 0 is returned, a non-zero failure code otherwise.