From: users-bounces@ovirt.org <users-bounces@ovirt.org> on behalf of Allen Belletti <allen@ggc.edu>
Sent: Wednesday, October 02, 2013 4:40 PM
To: users@ovirt.org
Subject: [Users] Customizing node configuration

Hello All,

I've been searching the archives and not yet managed to find anything on the subject, so I'm hoping that someone can point me in the right direction.

I am using nodes with Intel 10G network cards. The driver for these cards has been tweaked to complain (and fail to start the interface) if a non-Intel approved optical transceiver is in use. It's easy to override with the following options:

ixgbe.allow_unsupported_sfp=1

The usual ways of doing this are either to place it on the kernel command line at boot time, or in /etc/modprobe.d/ixgbe.conf where it would read "options ixgbe allow_unsupported_sfp=1". Unfortunately I have no idea how to make either of these permanent on an oVirt node.

I'm running the ovirt-node-iso-3.0.1-1.0.2.vdsm.el6.iso image. It has an /etc/modprobe.d directory where changes do not persist across reboots. It also has /config/etc where I've added modprobe.d and modprobe.d/ixgbe.conf. By adding this file to /config/files, I've been able to make it appear in /etc/modprobe.d at boot time. This has no effect. It appears to take place after the ixgbe driver has already been started. If I "rmmod ixgbe" and "modprobe ixgbe" manually, it works fine.

So the general question is, how do I make configuration changes which persist across reboots? Surely others have run into the same situation when trying to support specific devices.

rc.local is probably the easiest way for now. There's a patch at http://gerrit.ovirt.org/#/c/19811/1 which gives us the ability to arbitrarily modify boot loader arguments, but I'm not sure that we have any plans to add a field in the TUI to do so, though it may be a good idea, since this is coming up more and more often.