From build logs on my home project on OBS, I found these dracut modprobe fatal
errors both for Leap and Tumbleweed builds. 
In all the cases the builds were not aborted due to these errors. 

The missing modules were: kqemu, ext2, ext3, nf_conntrack_ipv6, ibmvscsi and
ibmveth.
The workers were: lamb04 and cloud112 but I had the same error also on lamb26

--------
[    4s] ### VM INTERACTION START ###
[    4s] Using UART console
[    4s] /usr/bin/qemu-kvm -nodefaults -no-reboot -nographic -vga none -cpu
host -object rng-random,filename=/dev/random,id=rng0 -device
virtio-rng-pci,rng=rng0 -runas qemu -net none -kernel
/var/cache/obs/worker/root_9/.mount/boot/kernel -initrd
/var/cache/obs/worker/root_9/.mount/boot/initrd -append
root=/dev/disk/by-id/virtio-0 rootfstype=ext4 rootflags=noatime
ext4.allow_unsupported=1 mitigations=off panic=1 quiet no-kvmclock
elevator=noop nmi_watchdog=0 rw rd.driver.pre=binfmt_misc console=ttyS0
init=/.build/build -m 8192 -drive
file=/var/cache/obs/worker/root_9/root,format=raw,if=none,id=disk,cache=unsafe
-device virtio-blk-pci,drive=disk,serial=0 -drive
file=/var/cache/obs/worker/root_9/swap,format=raw,if=none,id=swap,cache=unsafe
-device virtio-blk-pci,drive=swap,serial=1 -serial stdio -chardev
socket,id=monitor,server,nowait,path=/var/cache/obs/worker/root_9/root.qemu/monitor
-mon chardev=monitor,mode=readline -smp 8
[    4s] c[?7l[2J[0mSeaBIOS (version
rel-1.12.0-59-gc9ba527-rebuilt.opensuse.org)
[    7s] Booting from ROM..c[?7l[2J[    3.179259] dracut-pre-udev[257]:
modprobe: FATAL: Module kqemu not found in directory
/lib/modules/5.8.7-1-default
[    7s] [    3.190238] dracut-pre-udev[259]: modprobe: FATAL: Module ext2 not
found in directory /lib/modules/5.8.7-1-default
[    7s] [    3.194645] dracut-pre-udev[260]: modprobe: FATAL: Module ext3 not
found in directory /lib/modules/5.8.7-1-default
[    8s] [    3.859602] dracut-pre-udev[272]: modprobe: FATAL: Module
nf_conntrack_ipv6 not found in directory /lib/modules/5.8.7-1-default
[    8s] [    3.966635] dracut-pre-udev[283]: modprobe: FATAL: Module ibmvscsi
not found in directory /lib/modules/5.8.7-1-default
[    8s] [    3.990805] dracut-pre-udev[286]: modprobe: FATAL: Module ibmveth
not found in directory /lib/modules/5.8.7-1-default
[    9s] ### VM INTERACTION END ###
--------