Ubuntu Manpage: systemd-machine-id-setup - Initialize the machine ID in /etc/machine-id

Provided by: systemd_251.4-1ubuntu7_amd64

NAME

       systemd-machine-id-setup - Initialize the machine ID in /etc/machine-id

SYNOPSIS

       systemd-machine-id-setup

DESCRIPTION

       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 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 Interface[1].

        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.

OPTIONS

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.

--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.

--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.

--print
Print the machine ID generated or committed after the operation is complete.

-h, --help
Print a short help text and exit.

--version
Print a short version string and exit.

EXIT STATUS

       On success, 0 is returned, a non-zero failure code otherwise.

NOTES