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On Thu, 15 Feb 2001, Kyle Sparger wrote:
> I've found an interesting, but not totally unexpected race condition
> under DR in 2.2.x that I've managed to create when installing VIP's on a
> machine in DR mode, and I figured I'd stick it on the list in case someone
> else runs into it later.
I'll stick it in the HOWTO.
> Basically, the cause is this:
>
> ifconfig dummy0 10.0.1.15
> echo 1 > /proc/sys/net/ipv4/conf/dummy0/hidden
>
> You'll notice that there's going to be a small gap between the two which
> allows an ARP request to come in, and for the server to reply. And yes,
> it is big enough to be bitten by -- I've been bitten twice by it so far :)
>
> The question then is, how do I solve it?
>
> Try changing the order to this:
>
> echo 1 > /proc/sys/net/ipv4/conf/default/hidden
> ifconfig dummy0 10.0.1.15
> echo 0 > /proc/sys/net/ipv4/conf/default/hidden
>
> That way, it defaults to being hidden when it's first created.
does it work?
why do you echo the "0"?
My preferred way of handling the arp problem is by having a host route on
the router to the VIP which goes to the director and not allowing packets
to the VIP to get onto the real-server network. This option is not always
available (eg if you don't control the router).
Joe
--
Joseph Mack mack@xxxxxxxxxxx
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