Virtual machines network (Xen)

Dear openSUSE Community,
I’m using Xen to virtualize some Windows and Linux servers.
Currently I’m using two machines, one for production, which runs Xen 3.2.1 with Debian5 Dom0 and the second one (Xen 4.0.1, openSuse 11.4 dom0) for development/testing.
I’m experiencing some problems with an HVM linux domU over the openSUSE machine.
In particular, the linux domU runs network services (web server, ssh), and, periodically, in an intermittent manner, the domU’s network goes off.
I realized that the vnc console attached to the domU still works, i.e., the domU is responsive, while the network doesn’t work.

The host machine is underloaded, i.e., it runs just two hvm domUs (the linux domU and an idle windows domU).
To figure out the problem, I run a simple ping test from my laptop to both domUs runinng on my server. The ping test shows that both domU suffers intermittent connectivity. More interestingly, when a domU network works, the other domU’s network doesn’t and viceversa. (In the meantime, the dom0 network is always responsive)
So it seems a “network scheduling” problem among virtual machines.

I already posted this issue on the xen users mailing list, but given the use of standard linux tools (such as linux bridge i.e., brctl) to provide virtual machines networks, I’m trying to get some help also from the openSUSE community.
Any hint is appreciated, I’m trying to use openSUSE as standard virtualization container for a my company project, but I can’t do that without solving this issue!



I believe that it’s some sort of configuration problem or bug. I have no experience with running xen on openSUSE but I have a lot of experience with running Citric XenServer 5.5U2 so more likely I would be able to help You with that :slight_smile: and I can reccomend XenServer as I think it would be much easier to use as a standard virtualization container.

Back to openSUSE :slight_smile: Have You read this already ?
Chapter 23. Basic Networking

IMHO it’s very comprehensive but well writen and easy to understand. Maybe it will help You solve your problem or provide some other interesting information here.

Best regards,

Thanks for the reply, after some work I find out the problem. It was a misconfiguration issue: the VMs’ configuration files were copied from the same source-template, that for a mistake had a MAC address specified for its virtual NIC. Hence, both virtual machines were configured to use the same MAC address.


Thank You for posting the solution here. I’m glad You got it up and running.

Best regards,