This is a work in progress, your milege may vary
Install, start/stop service functional
git clone https://github.com/seraphin/tachyon-service.git /var/lib/ambari-server/resources/stacks/HDP/2.2/services/tachyon-service
ambari-server restart
Add service via ambari ui
Select a master server node and worker nodes
set tachyon.master.address = to tachyon master servername
set tachyon.underfs.address = hdfs://namnode:8020
set tachyon.worker.memory = a resonable amount of ram per server. Master also runs a worker
Needs code for service status check