Hadoop is a large scale distributed data storage and processing infrastructure using clusters of commodity hosts networked together. Monitoring and managing such complex distributed systems is a tough task. To help you deal with the complexity, Apache Ambari collects a wide range of information from the cluster's nodes and services and presents them to you in an easy-to-read format. It uses a centralized web interface called the Ambari Web. Ambari Web displays information such as service-specific summaries, graphs, and alerts. It also allows you to perform basic management tasks such as starting and stopping services, adding hosts to your cluster, and updating service configurations.
For more information on Administering Hadoop using Apache Ambari, see Administering Hadoop 2 with Ambari Web guide on Hortonworks Data Platform website.