Hyper-V Core HA Cluster

Hi, 

I am bulding a Highly available cluster from two Hyper-V 2012R2 core nodes and need to clear some things.

I would like to know, how to solve AD, when I need the domain controller Highly available.

I thought I would have one domain running on a separate server (third server, not a node of a cluster), just for the cluster and Hyper-V services and a second one, running the whole Company domain.

Can this be solved another way? E.g. installing full WS2012R2 as nodes and using them as domain controllers? I would like to avoid having another server running. 

Thank you.