[Xen-users] RE: Xen-users Digest, Vol 81, Issue 28

[<ray@xxxxxxxxx>]

Date: Mon, November 14, 2011 4:51 am
To: xen-users@xxxxxxxxxxxxxxxxxxx
Date: Mon, 14 Nov 2011 08:04:11 +0100
From: Simon Hobson <linux@xxxxxxxxxxxxxxxx>
Subject: Re: [Xen-users] New Install Plan Help - NIC Requirements
To: xen-users@xxxxxxxxxxxxxxxxxxx
Message-ID: <p06240874cae66c43b26c@xxxxxxxxxxxxxxxxxxxxxx>
Content-Type: text/plain; charset="us-ascii" ; format="flowed"

>They both have a single on-board Ethernet port. I am wondering 
>about the possibility/need to have a 2-port plug-in NIC. A scenario 
>is to have a domU Windows or Linux SVN/Apache/PostgreSQL VM and 
>interact with it through another domU Windows or Linus VM. I also 
>may want to remote in from the Internet or a Windows remote desktop 
>through a domU Windows VM.

None of that needs more than one NIC.

Imagine if any bridge(s) you set up to connect guests to are 
switches, and each guest is a real machine - do you *need* more than 
one connection to the rest of your network for everything to work ? A 
fairly typical setup (at least to start with) is to create one bridge 
in your host, connect one external NIC to it, and connect all your 
guests to it. Then all your guests appear to be on one network - just 
as though they were physical machines plugged into one switch.

Even if you want multiple networks (eg for a DMZ, office internal 
network, public wireless, etc) then these can still be done with one 
NIC and VLANs if you have a VLAN capable switch. On the other hand, 
it can be easier to manage and setup to use separate NICs for each 
separate network.

Really, it's a case of working what your needs are, and then 
addressing them. There isn't a right or wrong way (though some are 
better or worse than others), just an optimal way for your 
requirements.
-- 
Simon Hobson
______________
Simon,

Thank you for your efforts in producing the detailed explanaition.  That
is just what I was looking for.  It sounds like there is an underlying
technology behind all the VMs bridged to a NIC.  Can you suggest some
search phrases or specific links that might help me learn more about
this?

ray




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