To run:
ssh-keygen -f id_rsa -t rsa -q -N ""
heat stack-create -f rpc_multi_node.yml rpc "key_name=<keyname>;rpc_version=<branch/tag>" -t 150
(Replace <keyname> with your nova key and <branch/tag> with the desired RPC version to deploy)
Failing to specify -t 150 will result in the stack-create timing out and failing as a result.