Mailing List Archive

Hello,

On Thu, 4 Jan 2001, S. Effendi wrote:

> Hi!
>
> I'm new to this LVS :)
>
> We've been trying to install LVS, and so far so good, cause we're able
> to connect from outside the LVS, i.e. HTTP request, MySQL request and so
> on, are load balanced and served as we hoped.
> Our site:
>
> [internet]
> ||
> [switch1]
> ||
> [router1]==heartbeat==[router2]
> || ||
> [switch2] --+ [switch3]--+
> | | | | | |
> [rs1] [rs2] [rs..] [rs12] [rs22] [rs...2]
>
> Our VIPs are in the network: 64.39.1.x
> Our IPs are in the network: 10.1.2.x
>
> Our client (webbrowser) is able to reach our real web server from
> internet.
> But we have this problem:
> We are using internally (inside LVS) http protocol, and some pr*p-
> protocol to communicate between our realservers using "hostnames
> resolved with our VIPs". We could not reach our real server from other
> real server inside the LVS using the VIPs.
> Could it be that we have misunderstood the concept of LVS?
> The CLIENT of LVS can also be the real server inside the LVS also, can't
> it?

LVS/DR setup? If yes:

The clients in the real servers connect to the local
service when using VIP as dest addr, not to the director. The routing
does not pass the requests to the director. You can't use the VIP as
source addresses too if this breaks other rules. But in some situations
you can make connections from the real server with saddr=VIP, of
course, to remote host that will ack the connection. This is not the
case with the director. May be you have to change your pr*p-protocol.
You have to use unique IP addresses when communicating. May be there are
some exotic solutions to this problem which may include advanced
routing but I'm not sure. And there are so many reserved network
addresses that can be used for such talks.

If this is LVS/NAT setup you again can't connect to VIP
in the director from the real servers. In this case the real servers
see that the clients are onlink and ignore the director. This avoids
the NAT processing and the connection can't be established.

So, it seems there is no way to run clients in the real
servers and they to connect through the director. Or may be I'm wrong?

> Thanks for any help.
>
> Best regards,
> S. Effendi


Regards

--
Julian Anastasov <ja@ssi.bg>