Last time I looked at gluu it seemed massive, requiring a beefy server dedicated to running it. It came with an ldap server etc, meaning I seemingly couldn't us my own. I'll have to revisit, but last I checked its way too much.
Bookmarked, thanks. I'll be sure to try gluu again and giving it its own server if u2f becomes a requirement, or if I need any of the other features it offers.
All I need is an openid server.