Comment # 4 on bug 1173402 from Thomas Blume

(In reply to Fabian Vogt from comment #3)
> Dammit. I did some more tests meanwhile and it doesn't work in some cases,
> presumably in those where there were no ifcfg-* files copied into the initrd.
> It still acquires an IP over DHCP, but the dracut initqueue times out anyway.
> 
> Any idea what could be used as a workaround?

dhcp is the fallback, if there is no ip= config given.
Maybe it doesn't try all interfaces then.
But better I check the boot log.
Could you provide a log from a failing boot with the rd.debug boot parameter?