How to use those files:
1- with heat command line client:
 - heat stack-create <name> -f hadoop/hadoop-cluster.yaml -e hadoop/example-env.yaml 
 - heat stack-create <name> -f hadoop/hadoop-cluster.yaml -P "key_name=my_key;public_net_id=<pub_net_id>;private_net_id=<priv_net_id>;private_subnet_id=<subnet_id>"
2- with horizon:
 - login horizon:
  > Orchestration 
   > Stacks
    > Launch stack 
     > select file in "Template Source":
      > browse to get the hadoop-cluster.yaml
    > click on next
     > fill out the needed 
      key_name: put the name of your ssh key
      public_net_id: id of the public network, from "neutron net-list" command.
      private_net_id: id of the private network, from "neutron net-list" command.
      private_subnet_id: id of the private subnet, from "neutron subnet-list" command.
      note: password for user "username" is not required, just type a random string into the field