At which point you would like HA?
Database level? Possible if Oracle has any HA procedures, but don't think DLP will recommend it. There's no information about it in the Oracle Installation Guide.
Endpoint Server? Possible. Just having two Endpoint Server set up and direct the agents installed to different groups, and these groups be applied to each server specificly.
Single Tier itself is joining both roles in one server. This is a total different scenario.
Hope it helps!