[lvs-users] LVS-DR on default gateway

Dennis J. dennisml at conversis.de
Wed Jan 20 16:34:19 GMT 2010


On 01/20/2010 03:03 PM, L.S. Keijser wrote:
> Hi Dennis,
>
> On Wed, 2010-01-20 at 14:08 +0100, Dennis J. wrote:
>> Hi,
>> I'm trying to set up a couple of realservers behind a
>> gateway/router/firewall and would like to put the LVS-DR config on that
>> machine too. In another setup I'm already running LVS-DR but there the
>> director is not sitting between the client and the realservers.
>> I've read the documentation and googled around and found that the
>> director/gateway combination only works with patches applied and some
>> additional non-standard configuration steps.
>> What I'm wondering is if there is an easier way to accomplish this now? The
>> references I found on the web go all the way back to 2001 and talk about
>> 2.2 and 2.4 kernels so I'm not sure if the patches/hacks to make this work
>> are still valid or if there is an easier way to accomplish this nowadays?
>
> I assume by all this you mean solving the ARP problem. If so, take a
> look at this section of the HOWTO which is specific on 2.6 kernels:
>
> http://www.austintek.com/LVS/LVS-HOWTO/HOWTO/LVS-HOWTO.arp_problem.html#2.6_arp
>
> In a nutshell: you don't need to patch anything, just set some proc
> values and bring up a loopback device (in that order).
>

I should have mentioned that I'm not talking about the arp problem as I've 
already dealt with that in the other setup. What I'm talking about is the 
martian problem: The fact that the gateway gets confused because it sees a 
packet from a source IP that is also configured on a local interface (the 
VIP). That's not in issue in the working setup because the packets don't 
run through the director again on their way back to the client but since I 
want to run LVS on the gateway itself I need a way to get the packets past 
the mechanism that discards the packets on their way back.

Regards,
   Dennis




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