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Dan Trainor wrote:
Hello, all -
I have been doing some research on LVS-DR, and I think this is the
method for which I want to go ahead with, but first, I had some questions.
Looking at the LVS-HOWTO, I see the first example under chapter 6, at
http://www.austintek.com/LVS/LVS-HOWTO/HOWTO/LVS-HOWTO.LVS-DR.html. The
first example explains a sample setup, with a client, a director, and
various realservers.
My question is, when using the following diagram (taken from the HOWTO):
Host IP
client CIP=192.168.1.254
director DIP=192.168.1.1
virtual IP (VIP) VIP=192.168.1.110 (arpable)
realserver1 RIP1=192.168.1.2
VIP=192.168.1.110 (lo:0, not arpable)
realserver2 RIP2=192.168.1.3
VIP=192.168.1.110 (lo:0, not arpable)
realserver3 RIP3=192.168.1.4
VIP=192.168.1.110 (lo:0, not arpable)
.
.
realserver-n 192.168.1.n+1
...does this imply that the realservers and the director share a common
IP that needs to be on a routable network, or were nonroutable networks
used here just for the sake of example?
The director advertises the VIP. It directs requests for TCP/UDP based
services to the real servers. Hence it makes services of the real
servers to appear as a virtual service on a single IP address. LVS-DR
can be implemented in any network segment with public or private adresses.
If the realservers need to
respond the client directly in an LVS-DR setup, do they need to be made
aware of which netwrk they're on, to grab a default gateway and such to
appropriately map a request back to a client?
Real servers need to have a default gateway, ... etc
If we're not using ARP
for these VIP interfaces, wouldn't this be a problem?
No, please read:
http://www.linuxvirtualserver.org/VS-DRouting.html
I wouldn't call
myself a networking newbie by any means, but this is something that I
don't quite understand. If the opposite were true, and the realservers'
VIPs were routable IPs, then I suppose it would not be much of a
problem? I'm not sure, this is where I'm hoping you guys step in and
teach me a lesson :)
My understanding is that the director and realservers share a VIP, which
should/may/can be a non-routable IP, which would open up some IP space
for other network services to use the same network or subnetwork. In
fact, if this is the case, then I think the setup I want to work with,
will work appropriately.
Were are your end clients? Do they have a public or private IP addresses?
Regardless, I am a bit confused, and would very mcuh appreciate it if
someone were to straighten things out for me.
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