RE: [Xen-users] Server with 2 NICS; connect domU to outside & vlan

["Ferreira, N.L." <N.L.Ferreira@xxxxx>]

Hey Thomas


-----Original Message-----
From: Thomas Halinka [mailto:lists@xxxxxxxxx]
Sent: Mon 30-Mar-09 10:44 PM
To: Ferreira, N.L.
Cc: xen-users
Subject: Re: [Xen-users] Server with 2 NICS; connect domU to outside & vlan

>
> What I have:
> 1) A dom0 server with 2 NIC cards (eth0, eth1), running centOS52 xen
> 3.2.
> 2) A switch to a VLAN with several physical machines (already up and
> running).
>
> What I need:
> 1) A domU with a static IP and also connected to the VLAN.

|you need to write your own networking-script to use 2 bridges.
|
|# vim /etc/xen/scripts/network-2nics
|
|#!/bin/bash
|/etc/xen/scripts/network-bridge $1 netdev=eth0 bridge=xenbr0 vifnum=0
|/etc/xen/scripts/network-bridge $1 netdev=eth1 bridge=xenbr1 vifnum=1
|
|# chmod a+x /etc/xen/scripts/network-2nics
|
|edit xend-confix.sxp
|
|and finally restart xend.
|
|To use 2 bridges/NICs into your guests, just use something like:
|
|vif         = [ |'ip=xxx.yyy.zzz.228,mac=00:01:ad:13:04:05,bridge=xenbr0','ip=10.0.57.228,mac=00:16:3E:3C:B3:FC,bridge=xenbr1' |]

So if I understood correctly, this creates 2 bridges, one per dom0 NIC.
Then, domU interacts with these two bridges, giving the right IP's and MAC addresses.

About the xend-confix.sxp edition (next lines), are they correct?:

[... snipped ...]
#(network-script network-bridge)
(network-script 'network-2nics')
[... snipped ...]



> My plan:
> 1) use dom0 eth0 to connect to the outside world; domU will use it also
> to connect to the outside (this is the default anyway).
> 2) use dom0 eth1 to connect domU to the switch connected to the VLAN.
>
> Do not know if this makes much sense, it makes to me at least,.

|So:
|
|- do you want to NATting in dom0? ---> use network-nat ;)
|- Or do you want a router in domU ---> follow the above :-)
|

Can't comment on that. Only trying to put 2 NICs working such that a domU can use them. And at the same time, learning a lot but having to put effort on this task.

>
> My progress:
> [root@dom0 ~]# ifconfig
> eth0      Link encap:Ethernet  HWaddr 00:E0:81:4D:30:D0

|
|....  it's not a good idea to post your public-ips :-)
|

Thanks for the tip.
Those were not my public ips. Scrambled them, maintaining only the logic.
xxx.xxx.... would be more appropriated nevertheless.

> xenbr1    Link encap:Ethernet  HWaddr FE:FF:FF:FF:FF:FF
>         
>
> So it seems that the dom0 is well configured, both to the outside world
> and to the VLAN. Though I thought 2 xen bridges should appear ... one
> for each NIC card?

|
|yap, but the standard-network-script wont do this 4 you.
|

Got it. Already answered by you a few lines above

>
> I booted a domU (after changing in the xen cfg file xenbr0 to xenbr1)
> created is this machine (when the eth1 was still inactivated) and I had
> problems because Kudzu detected a change in the network configuration.
> So probably, I should create the domU when both dom0 NIC cards are
> active, right?

|
|yap. if i understand you right, you wand to use a domU as router?
|
|So you need _a_ domU with 2 nics (connected to internal _and_ external
|bridge), whcich does the job for you.
|

Again, I feel a bit dumb here. Have to read more about bridges, routers, NAT's and so on.
But yes, the goal is to have domU with 2 NICS. So I thought that if dom0 has 2 physical NICS, I could use both for network performance, and to pin dom0 eth0 to the corresponding one at the domU, and the same for the 2nd NIC.

Going from the wet-lab to this in-silico IT crazy world, is per se an odyssey.

Thanks for your time.
Nuno

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