informations about boot sequence (Re: F15 - mysql start problem)

[Lennart Poettering]

On Tue, 10.05.11 01:04, Miloslav Trmač (mitr at volny.cz) wrote:
> 
> ... rereading the thread, the thing I have missed is that we don't
> want to block startup in configurations where the server binds to
> 127.0.0.1 because the system might never come online. So there appears
> to be no universally correct default for programs with flexible bind
> addresses :(
>    Mirek

Note that the loopback device is actually configured as one of the first
things in systemd, from within PID 1. On a systemd system 127.0.0.1 and
::1 are always bindable, the network scripts or NetworkManager do not
need to set them up manually anymore.

That basically means that on a systemd system a service can always bind
to 0.0.0.0, ::, 127.0.0.1, ::1. Only if it needs a different IP address it
can resort to IP_FREEBIND, or even better netlink notifications.

Lennart

-- 
Lennart Poettering - Red Hat, Inc.