Appendix C. Known issues

This is the list of known issue with the KVM roll:

  1. Ethernet channel bonding does not work with the KVM roll (rocks add host bonded).

  2. Nvidia MCP77 integrated Ethernet Controller does not handle properly vlan tagged packages, so virtual clusters will not work on this hardware.

  3. We have found that when a virtual frontend and a virutal compute node run on the same physical node it is necessary to disable tx checksumming offload on the eth0 in order to properly install the compute node. If during PXE boot compute node fails with "Connection timed out" error message run the following command on the frontend:

    ethtool -K eth0 tx off

    To make this change persistent after a reboot add that line in /etc/rc.d/rc.local of your fronend.

  4. If you have a Frontend node and a compute node connected directly with a cable (and no switch in between), you have to change the STP parameters of the private network bridge otherwise the installation of virtual cluster nodes will fail. To do this run:

     brctl setfd eth0 1.00
     brctl sethello eth0 0.5