I would like to add CoreOS as a supported OS type to cloudstack. CoreOS vms can be created even now by selecting OS type as "Other". There are cloud providers supporting CoreOS offerings in production already. By making the changes mentioned at [1] I would make it easier to deploy CoreOS Vms and also add UI support for providing cloud-config via userdata. I'll also update the documentation at [2] after making these changes.
[1] https://cwiki.apache.org/confluence/display/CLOUDSTACK/CoreOS [2] https://coreos.com/os/docs/latest/booting-on-cloudstack.html