Was able to build a 2.8 3-node cluster last week and get the messaging service happy.  I didnt the std install and clone, and then followed the steps on pages 7-9 of this whitepaper to get the elastisearch, rabbitmq, and ehcache services running smoothly

http://blogs.vmware.com/euc/2016/12/vmware-identity-manager-configuring-multiple-data-centers.html

The paper is mainly for a multi-datacenter design, but the steps can still be utilized for a single datacenter cluster for the most part.