systemd Developer Didier Roche didrocks@ubuntu.com systemd-machine-id-commit.service 8 systemd-machine-id-commit.service Commit transient machine-id to disk systemd-machine-id-commit.service /usr/lib/systemd/systemd-machine-id-commit systemd-machine-id-commit.service is a service responsible for commiting any transient /etc/machine-id file to a writable file system. See machine-id5 for more information about this file. This service is started shortly after local-fs.target if /etc/machine-id is an independent mount point (probably a tmpfs one) and /etc is writable. systemd-machine-id-commit will then write current machine ID to disk and unmount the transient /etc/machine-id file in a race-free manner to ensure that file is always valid for other processes. Note that the traditional way to initialize the machine ID in /etc/machine-id is to use systemd-machine-id-setup by system installer tools. You can also use systemd-firstboot1 to initialize the machine ID on mounted (but not booted) system images. The main use case for that service is /etc/machine-id being an empty file at boot and initrd chaining to systemd giving it a read only file system that will be turned read-write later during the boot process. There is no consequence if that service fails other than a newer machine-id will be generated during next system boot. systemd1, systemd-machine-id-commit1, systemd-machine-id-setup1, machine-id5, systemd-firstboot1