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Hi all.
I have been struggling with a setup for a good while now.
Requirement:
Clients need to connect to a variety of services from external ip addresses.
However real servers need to connect to a vip balanced between each
other for mysql connections.
We are using LVS-DR for the external connections and alls well. As
expected the problem is when the realservers need to be clients. To make
things possibly worse those real server are freebsd so i can't apply any
of the realserver patches for linux.
What i tried to work around the problem is to add two nics to each
realserver and the load balancer. Link all ext nics on one switch and
all int nics on another switch.
I thought of running the services required by external clients in LVS-DR
and the mysql needed by the real servers in LVS-NAT.
Diagram to help
router
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| ext if's int if's
--------- director--------
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--------- real server 1---
| |
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--------- real server n---
On the ext side i add the VIP1 which is created on the director ext_if
to the localhost of each server as an alias. Setup LVS-DR and works fine.
Now I can't connect to a balanced service on VIP1 from a real server
since it always looks at itself - right.
Si i created a second vip VIP2 on the director ext_if in another subnet
separate from the ext and int nets. I then set the director to nat all
addresses from the ext side, set routes on the realservers to reach the
VIP2 and balanced the director to forward the requestes to the
realservers int_if ip's.
That doesn't work and my knowledge of ip is not that good for an
explanation. I assumed that since the director is natting all packets
leaving its int_if that the real servers would reply to the directors
int_if.
Can anyone suggest a solution or at least show me the flaws in this sort
of setup. I desperately need to balance the mysql services with the real
servers as clients.
Leon
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