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On Sun, 30 Sep 2001, Serge Sozonoff wrote:
> Hi Adrian,
>
> Thanks for this info. I will try and clarify myself a bit more and ask
> my question the other way around.
> These are my requirements:
>
> Using LVS-NAT I would like to:
>
> 1. Load balance my servers.
> 2. Have access to each real server individually from the internet by IP
> address bypassing the LD (Real Servers have a valid IP)
> (i.e. I am NAT'ing, but only for the purpose of load balancing, not for
> having a private network behind the LD)
> 3. Use the Router or the Linux Director as the default gateway for
> return traffic.
As long as there is no direct layer2 link between real servers and router, all
packets will pass through the LVS director. A packet coming from a client will
end either on the director's IP (for load-balancing) or will pass the director
(processed by the bridging code) and will arive to the server. The return
packets in turn, will pass by default through the director NOT being processed
bye layer3 code (and LVS). However, if you proxy-arp the router's IP on the
interface that faces the real servers, the packets will get out of the
bridging code and will be injected in the layer3 (IP) code where LVS can do
the job.
There is however a drawback: you can't directly access a load-balanced
service (any real service - IP:port pair - that is in LVS table is accessible
only via LVS). If you want to access such a service duplicate it either on a
different port or on a different vhost/IP. To avoid this you may replace
LVS-NAT with LVS-DR (that does not process the return packets). See below.
>
>
> It might look something like this: (IP addresses are hypothetical)
[stripped]
> Is it possible to load balance on MAC address's ?
>
> Cisco Local Director dispatch mode -> With dispatch mode, the
> LocalDirector simply performs a MAC address translation leaving the IP
> header of the packet intact.
That is LVS-DR. If you use it you have all chances that none of the
above-mentioned problems occur. Just read the howto to avoid the ARP problem
(or use static ARP on the director).
>
> Some links regarding Cisco LD
> http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/transbdg.htm
> http://www.eecostructure.com/blueprint_rec/implement_network_cisco_local
> director_configuration.htm
Radu-Adrian Feurdean
mailto: raf @ chez.com
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Microsoft is the C:\ of all evil
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