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 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
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
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.
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 Container
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 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.
Print the machine ID generated or committed after the
operation is complete.
Print a short help text and exit.
Print a short version string and exit.
On success, 0 is returned, a non-zero failure code otherwise.