Xen users - Jun 2010 - Private Networks between domUs on multiple hosts

I''ve found xen networking quite hard to get the hang of and would
appreciate some pointers in the right direction on how to network domUs into
their own private networks across multiple servers. There are, say, 5 guests on
one machine and 5 on another but I would like to be able to allow them to only
''see'' fellow guests which are linked to their virtual network.
At the moment all guests can contact each other - they''re on the same
network.

I understand this could be achieved with vlans and whilst I''ve used
these before outside of Xen, I''m unsure of how to do so within
xen''s networking system. I''m sure my query isn''t
uncommon and so was hoping that someone would know of an easier way in which
what I want can be achieved using pure Xen functionality.

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ive not done it with xen, but i''ve had similar thoughts:

- if you''re running xVM or xen on a solaris dom0 try crossbow
- configure a tagged vlan interface on the hypervisor, and presentto the domU
(i.e. eth0.1).  then set the MTU down accordingly

----- Original Message -----
From: "Joe" <cycloned@me.com>
To: xen-users@lists.xensource.com
Sent: Tuesday, June 29, 2010 1:35:16 PM
Subject: [Xen-users] Private Networks between domUs on multiple hosts

I''ve found xen networking quite hard to get the hang of and would
appreciate some pointers in the right direction on how to network domUs into
their own private networks across multiple servers. There are, say, 5 guests on
one machine and 5 on another but I would like to be able to allow them to only
''see'' fellow guests which are linked to their virtual network.
At the moment all guests can contact each other - they''re on the same
network.

I understand this could be achieved with vlans and whilst I''ve used
these before outside of Xen, I''m unsure of how to do so within
xen''s networking system. I''m sure my query isn''t
uncommon and so was hoping that someone would know of an easier way in which
what I want can be achieved using pure Xen functionality.

_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

> -----Original Message-----
> From: xen-users-bounces@lists.xensource.com [mailto:xen-users-
> bounces@lists.xensource.com] On Behalf Of Joe
> Sent: Tuesday, June 29, 2010 3:35 PM
> To: xen-users@lists.xensource.com
> Subject: [Xen-users] Private Networks between domUs on multiple hosts
> 
> I''ve found xen networking quite hard to get the hang of and would
appreciate some
> pointers in the right direction on how to network domUs into their own
private networks
> across multiple servers. There are, say, 5 guests on one machine and 5
on another but
> I would like to be able to allow them to only ''see''
fellow guests
which are linked to their
> virtual network. At the moment all guests can contact each other -
they''re on the
> same network.
Xen networking isn''t so bad once you understand Linux networking
(bridging).  I like to short-circuit network-script with something like:

(network-script /bin/true)

in xend-config.sxp so I can configure bridges and interfaces on my own.
> I understand this could be achieved with vlans and whilst I''ve
used
these before
> outside of Xen, I''m unsure of how to do so within xen''s
networking
system. I''m sure
> my query isn''t uncommon and so was hoping that someone would know
of
an easier
> way in which what I want can be achieved using pure Xen functionality.
On CentOS, I''ll paste a few configs that should be enough to get you
started.

In the domU config:

vif = [
        ''mac=00:16:3E:5E:A2:5C,bridge=public,
        ''mac=00:16:3E:77:64:14,bridge=private''
      ]

(In this example the domU has two interfaces, eth0 is routed to the
public internet, eth1 private amongst domU''s.)

In the bridge config:

# cd /etc/sysconfig/network-scripts

# cat ifcfg-private
DEVICE=private
TYPE=Bridge
BOOTPROTO=none
ONBOOT=yes

In the VLAN config:

# cat ifcfg-eth1
DEVICE=eth1
BOOTPROTO=static
ONBOOT=yes

# cat ifcfg-eth1.2001
DEVICE=eth1.2001
BRIDGE=private

Each domU can talk to the other domU''s over eth1, and the
dom0''s bridge
this traffic over VLAN # 2001.  The private bridge does not have an IP
address, so the dom0 is not reachable from the private network--it only
bridges traffic.

-Jeff



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