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 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
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
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
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
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.
systemd(1), machine-id(5), systemd-machine-id-commit.service(8), dbus-
1. Container Interface
systemd 237 SYSTEMD-MACHINE-ID-SETUP(1)
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