What OS image can I use for Docker Swarm in Magnum?

Hi,   I'm looking to set up Docker Swarm using Openstack Magnum and I noticed the user guide for magnum lists only Fedora Atomic as supported.  If I'm not mistaken though Atomic has been discontinued for a while now, so I'm wondering what you use for this use case.  Can I use Fedora CoreOS instead, and if so are there any gotchas I should know as a first time Magnum user? Thanks in advance, Paolo