http://capnjosh.com/blog/installing-hortonworks-hadoop-ambari-server/
4. in order to add machines to a cluster you need to have the ambari agent installed on each machine
– https://ambari.apache.org/1.2.0/installing-hadoop-using-ambari/content/ambari-chap6-1.html
– the Ambari wizard will do it automatically ONLY if you have ssh keys installed
– if you don’t have ssh keys installed you will have to manually install the ambari agent on each machine
– wget http://public-repo-1.hortonworks.com/ambari/centos6/1.x/updates/1.4.3.38/ambari.repo
– cp ambari.repo /etc/yum.repos.d
– yum install ambari-agent
– point the agent at the Ambari server
– nano /etc/ambari-agent/conf/ambari-agent.ini