> And is ambari1.example.com the host with Ambari Server (which is not part of the 4-hosts in the cluster master, node1, node2 and node3)?
Yup. Ambari Server is separate host not part of cluster.
> And is ambari1.example.com the host with Ambari Server (which is not part of the 4-hosts in the cluster master, node1, node2 and node3)?
Yup. Ambari Server is separate host not part of cluster.