In initrd, the NM service should write logs to both the active console
and the journal. To achieve that, NetworkManager is started with
--debug to output logs to stderr, and the systemd unit is configured
StandardError=tty to redirect messages to the console. NM is
logging.backend=journal to also save logs in the
journal. The problem of this approach is that when the system doesn't
have a console, the NM service fails to start .
This can be solved by using
forwards messages from stderr to journald (which in turn also writes
them to the console if available). To avoid duplicates entries in the
journal, we need a way to disable all logging backends in NM and only
write to stderr.
none logging backend. Of course, it's not recommended to
start NM without logging; therefore the
none backend can't be used
as build-time default.
none only makes some sense when also starting