Seems like I’m always working on installing more Xen servers.  We use SolusVM for our virtualization.  Today I working on another node for a customer and ran into an issue.

I installed a new CentOS 7 and perform the steps outlined in the Xen Quickstart, and then fixed a couple of issues from as i mentioned in Xen Hypervisor won’t boot, and Xen crashing blogs, next installed SolusVM, and started up a new VPS, however it failed right away.  I got the following error in the logs

RTNETLINK answers: Device or resource busy

I’ve done this a few times, and recall i had this same issue the last time i created a new guest on a recently installed Xen Dom0.

The issue has to do with NetworkManager, this needs to be disabled and turned off for Xen to work properly.

If you’re running CentOS 7.x, you can issue the following commands to disable and stop the service.

systemctl disable NetworkManager.service
systemctl stop NetworkManager.service

After doing that I went ahead and rebooted the server, and once the server can back online, the VM that i had just created was now running as expected.

Name                                        ID   Mem VCPUs	State	Time(s)
Domain-0                                     0  2048     4     r-----     143.9
vm135                                        1  2048     1     -b----      18.0

This was a good result. You would think when Xen installs it would automatically turn off something like NetworkManger so it’s not conflicting.