Comment 39 for bug 771372

Andreas, its likely that the update just fixed it for some use cases. However, I would have expected it to fix your particular use case, because your VLAN trunks should be up as soon as 'stopped networking' is emitted, since that is emitted as soon as 'ifup -a' exits.

The error you see is likely because there are modules loaded later that support your sysctl.conf settings, so some of them don't exist yet. It shouldn't cause serious issues, but if you want to debug it, perhaps add a 2> /run/sysctl.errors to see why it exitted.

As far as the libvirt issue, thats caused by libvirt's start on:

start on runlevel [2345] and stopped networking

This presents a potential race condition since 'stopped networking' may happen after runlevel [2345]

Your best bet for a workaround is probably to add another condition to procps so it reads

start on virtual-filesystems or stopped networking or starting libvirt-bin

That will ensure that it runs before libvirt-bin is started.

I do actually think the fix for this is not complete, as we should still be trying to set these sysctl settings before any services start on them. I think this will require a larger refactoring, which we've been discussing for the "Q" release cycle, so that there is a barrier between bootup activities and starting of services.. and that would be an abstract 'network-services' job.