systemd-machine-id-setup — Initialize the machine ID in /etc/machine-id
systemd-machine-id-setup 
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 randomly generated ID. See
                machine-id(5)
                for more information about this file.
This tool will execute no operation if
                /etc/machine-id is already
                initialized.
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.
If run inside a KVM virtual machine and a UUID
                is passed via the -uuid option this
                UUID is used to initialize the machine ID instead of a
                randomly generated one. The caller must ensure that the
                UUID passed is sufficiently unique and is different
                for every booted instanced of the VM.
Similar, if run inside a Linux container environment and a UUID is set for the container this is used to initialize the machine ID. For details see the documentation of the Container Interface.