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

Provided by: systemd_229-4ubuntu21.31_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 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
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=root
           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
           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.

       -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