I have these lines on every boot:

Bringing up network interface lo ... [OK]
RTNETLINK answers: File exists
RTNETLINK answers: File exists

What i was found about this "informative" message is, that it can be caused by the setting the same route more than once.

I think, that i comes from fact, that the lo interface is initialized twice, once by the /etc/init.d/loopback (enabled in the boot runlevel by openrc itself) and once by the /etc/init.d/net.lo (not exactly enabled, but run as dependency in default runlevel).

The message itself seems as harmless, but it shows, that we have done the same thing more than once. The problem is, that the net.lo is mentioned as dependency of mysql init scripts:

grep net.lo /etc/init.d/*
/etc/init.d/mysql:	use net.lo
/etc/init.d/mysql-s6:	use net.lo
/etc/init.d/mysql-supervise:	use net.lo