systemd-machine-id-setup(1) — Linux manual page


SYSTEMD-...ID-SETUP(1)  systemd-machine-id-setup  SYSTEMD-...ID-SETUP(1)

NAME         top

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

SYNOPSIS         top


DESCRIPTION         top

       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         top

       The following options are understood:

           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.

           Added in version 212.

           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.

           Added in version 249.

           Takes an image policy string as argument, as per
           systemd.image-policy(7). The policy is enforced when
           operating on the disk image specified via --image=, see
           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 "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.

           Added in version 227.

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

           Added in version 231.

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

           Print a short version string and exit.

EXIT STATUS         top

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

SEE ALSO         top

       systemd(1), machine-id(5), systemd-machine-id-commit.service(8),
       dbus-uuidgen(1), systemd-firstboot(1)

NOTES         top

        1. Container Interface

COLOPHON         top

       This page is part of the systemd (systemd system and service
       manager) project.  Information about the project can be found at
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       This page was obtained from the project's upstream Git repository
       ⟨⟩ on 2023-12-22.  (At that
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       (which is not part of the original manual page), send a mail to

systemd 255                                       SYSTEMD-...ID-SETUP(1)

Pages that refer to this page: systemd-firstboot(1)machine-id(5)lvmsystemid(7)systemd.directives(7)systemd.index(7)systemd-machine-id-commit.service(8)