Elasticsearch exposes a rich set of APIs, known as stats APIs, to monitor Elasticsearch at the cluster, node, and indices levels. Some of these APIs are _cluster/stats, _nodes/stats, and myindex/stats. These APIs provide state/monitoring information in real time, and the statistics that are presented in these APIs are point-in-time and in .json format. As an administrator/developer, when working with Elasticsearch, you will be interested in both real-time statistics as well as historical statistics, which would help you in understanding/analyzing the behavior (health or performance) of a cluster better.
Also, reading through a set of numbers for a period of time (say, for example, to find out the JVM utilization over time) would be very difficult. Rather, a UI that pictorially represents these numbers as graphs would be very useful for visualizing and...
