[lvs-users] ldirectord and kvm

Graeme Fowler graeme at graemef.net
Thu Jul 10 12:25:17 BST 2008


On Thu, 10 Jul 2008, "Heinz A. Krebs" <heinz at chemit.at> wrote:
> i'm trying to setup a load balancing system with 2 servers and with
> qemu-kvm-engines running inside. tried it already some days (various
> techniques), but could not succeed, so i'm asking for help, ...


> on Server 1:
> -------------------
> eth0 is bidged to br0, eth1 not used by now
> br0
> br0:1 (DIP)
> br0:2  (VIP)

Just to check - Server1 is the director, yes? Is this a VM, or the  
real hardware?

> the server is running qemu-kvm, with a virtual network-card connected to
> br0. the networkcard gets the address, with default
> gateway inside the virtual engine i'm running a
> nameserver

Again, to be clear - the "realserver" (in LVS terms) is a QEMU VM?

> relevant part of my ldirector.cf:
> virtual=
>         real= masq
>         service=dns
>         scheduler=rr
>         protocol=tcp
>         checktype=on
> and a similar entrie for ssh

You'd be much better off just doing one service at a time. Since SSH  
responds with a banner (DNS does not) please consider getting your LVS  
up and running using SSH alone.

> from the server i can:
> ssh       -> connection o.k.
> telnet 53 -> connection o.k.

Which means that the bridge device is working OK, at least locally.

> but from outside (CIP
> ssh -> no route to host
> telnet 53 -> connection refused
> ping ping is o.k.

Is a completely separate physical machine?

> tcpdump 'tcp port 53' says:
> 12:37:19.757766 IP > S
> 3157355270:3157355270(0) win 5840 <mss 1460,sackOK,timestamp 150219440
> 0,nop,wscale 6>
> so it seems that the packages reaches the server, but is not forwarded
> to the virtual machine ..

Which machine - real or VM - was that taken from?

Strip it back to SSH only, and try again. This time run a tcpdump on  
the director and the realserver (the QEMU VM) and see what you get.  
I'm fairly sure there's something basic going on here.


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