systemd-run-generator — Generator for invoking commands specified on the kernel command line as system service
systemd-run-generator is a generator
that reads the kernel command line and understands three
systemd.run= option is specified and followed by a command line, a unit named
kernel-command-line.service is generated for it and booted into. The service has
Type=oneshot set, and has
FailureAction=exit configured by default, thus ensuring that the system is shut down as soon as
the command completes. The exit status of the command line is propagated to the invoking container manager, if
this applies (which might propagate this further, to the calling shell — e.g.
systemd-nspawn(7) does this). If
this option is used multiple times the unit file will contain multiple
ExecStart= lines, to
execute all commands in order. The command is started as regular service, i.e. with
systemd.run_failure_action= to tweak
how to react to the process completing. In particular assigning "
none" will leave the system
running after the command completes. For further details on supported arguments, see
Use a command like the following to add a user to the user database inside a container run with systemd-nspawn(7):
# systemd-nspawn -D mycontainer -b systemd.run='"adduser test"'
(Note the requirement for double quoting in the command line above. The first level of quoting ('') is processed and removed by the command shell used to invoke systemd-nspawn. The second level of quoting ("") is propagated to the kernel command line of the container and processed and removed by systemd-run-generator. Both together make sure both words of the specified command line adduser test end up in the generated unit file together and are neither split apart by the command shell nor by the generator.)