Date: Tue, 25 Oct 2011 15:41:59 +0200 From: Paul Schenkeveld <freebsd@psconsult.nl> To: freebsd-stable@freebsd.org Subject: Re: ntpd couldn't resolve host name on system boot Message-ID: <20111025134159.GA96607@psconsult.nl> In-Reply-To: <20111025125108.GA87567@icarus.home.lan> References: <4EA5EBB5.3090101@quip.cz> <20111024232750.GA74032@icarus.home.lan> <B26B1B7BC38B4479B103B78B2175234D@multiplay.co.uk> <20111025010327.GA75437@icarus.home.lan> <20111025092012.GA41065@psconsult.nl> <20111025125108.GA87567@icarus.home.lan>
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On Tue, Oct 25, 2011 at 05:51:08AM -0700, Jeremy Chadwick wrote:
> On Tue, Oct 25, 2011 at 11:20:12AM +0200, Paul Schenkeveld wrote:
> > On Mon, Oct 24, 2011 at 06:03:27PM -0700, Jeremy Chadwick wrote:
> > > The one shortcoming of netwait is that it doesn't support waiting for
> > > multiple NICs. Some people have dual-homed environments where they
> > > really would like to wait for both, say, em0 and em1, to come up and be
> > > functional before any more scripts are started. I left that as a
> > > project for someone else, but it's something that should be added given
> > > its importance.
> >
> > How would you like to see multiple interfaces implemented:
> >
> > - All interfaces must be up at the same time
> > - Probe interfaces one by one, proceed to the next when an interface
> > up or bail out when any interface stays down until the loop times
> > out
>
> 1) Each interface should be checked in the order specified.
> 2) Each ping probe should be done using that interface (ping -I).
>From ping(8):
-I iface
Source multicast packets with the given interface address. This
flag only applies if the ping destination is a multicast address.
I believe that for unicast the interface used is determined by looking
up the destination address in the routing table (unless overridden by a
packet filter that changes the next hop). Another way to influence the
next hop selection and the outgoing interface is using setfib(1) but
apart from rc.d/jail I see no fib support in rc.conf at all.
> 3) In the case of success, the next interface should be checked (e.g. go
> back to step #1 but for the next interface defined.
> 4) In the case of failure, output a message on-screen (similar to what
> we already do) and continue on with the next interface check.
>
> So I imagine the variables for this would need to become something like:
>
> netwait_em0_ip="4.2.2.1 4.2.2.2"
> netwait_em1_ip="192.168.1.1 192.168.1.2"
>
> You get the idea -- think ifconfig_* in style.
This also suggests that ping can be forced to send out packets thru a
certain interface which I think is misleading.
Where I see the testing of multiple interfaces becoming important is in
the case where interfaces are bonded using lagg(4). I usually have RTP
disabled on server ports but started to see problems with ntpd and other
services when I started to use LACP trunks.
Paul Schenkeveld
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