Xen users - Nov 2011 - New Install Plan Help - NIC Requirements

I would like to understand what may be needed/useful for the system NIC.

My plan is to use an Asus mb, Sabertooth or Crosshair.  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.

BTW, I am reading "Running Xen: A Hands-on Guide to the Art of
Virtualization".  In chapter 2, p. 34, it addresses starting a new
Debian-based guest creation and it shows the resultant listing.  The narrative
states "The xmllib warning messages can be safely ignored in this
case".  The listing shows:

/usr/lib/python2.4/xmllib.py:9:  DeprcationWarning:

    The xmllib module is obsolete.   Use xml.sax instead.

warnings.warn("The xmllib module is obsolete.

 It doesn''t state what the case is and I am new enough not to
understand from the context.  Why would I not need to be concerned about the
warning?  Additionally, being new to Linux, I would like to understand how to
chase down warnings, errors, etc. While I can move forward just through neglect,
I old like to take a knowledgable step.

Thanks,

ray


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On Mon, Nov 14, 2011 at 7:11 AM,  <ray@aarden.us>
wrote:
> Additionally, being new to Linux, I would like to understand how to chase
> down warnings, errors, etc.
Short version, if you''re new to Linux, then don''t even bother
trying
to setup Xen manually. Just use the free vmware vsphere hypervisor,
oracle vm, or citrix xen server. All of them installs on bare metal
and has nice GUI, easy to use for beginners. For most purposes one
gigabit NIC + vlan-capable switch would be enough to simulate typical
datacenter network (e.g. DMZ, public, intranet)

Long version, Linux is not really the best OS when it comes to
compatibility. DIfferent versions of library, or different versions of
a program (e.g. Xen 3.x vs Xen 4.x) can produce different
warnings/errors or require different ways to setup. If you want to try
to setup Xen on top of Linux dom0 manually, I highly suggest you start
with distro-bundled Xen first. For example (the somewhat old but
rock-solid) RHEL/Centos 5.7, or (Open)suse, or certain versions of
Debian.

And if you''re following a tutorial (book, web page, etc), check on the
publication date and software versions mentioned there, just in case
it''s obsolete.

-- 
Fajar

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<ray@aarden.us> wrote:
>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

Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed
author Gladys Hobson. Novels - poetry - short stories - ideal as
Christmas stocking fillers. Some available as e-books.

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Sorry for the subject line error of the previous posting

Date: Mon, November 14, 2011 4:51 am
To: xen-users@lists.xensource.com
Date: Mon, 14 Nov 2011 08:04:11 +0100
From: Simon Hobson <linux@thehobsons.co.uk>
Subject: Re: [Xen-users] New Install Plan Help - NIC Requirements
To: xen-users@lists.xensource.com
Message-ID: <p06240874cae66c43b26c@simon.thehobsons.co.uk>
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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