Comment # 5 on bug 915849 from Andrei Borzenkov

This cannot work in systemd mode (that openSUSE uses); here is what dracut puts
into /etc/crypttab

echo "$luks $dev - timeout=0,$allowdiscards" >> /etc/crypttab

To actually make it work as is /supposed/ to work in systemd mode
90crypt/crypt-run-generator.sh would need

a) put keyfile in crypttab. Not sure when support appeared in systemd.
b) generate mount units to mount USB stick. And somehow unmount them before
switching root!

Current systemd already add RequiresMountsFor to crypto unit if keyfile is
specified, so it should be enough to ensure proper ordering.

This is actually upstream problem, upstream lacks proper support.