Install the epel repository:
yum install epel-release
Confirm the repository is configured by checking the repo list
yum repolist
You should see the Ambari, HDP utilities, and EPEL repositories in the list
repo id repo name AMBARI-1.x Ambari 1.x HDP-UTILS-1.1.0.15 Hortonworks Data Platform Utils Version - HDP-UT epel Extra Packages for Enterprise Linux 6 - x86_64
Install the Ambari bits using yum. This also installs PostgreSQL:
yum install ambari-server
