During my research in Hadoop applications that are developed, I found that three applications are so popular. Hadoop main architecture is to process both formatted and un-formatted data in lesser time with less expensive servers. Most of these concepts covered in good hadoop online training.
Popular hadoop real-time applications small video
One of the first real-time Hadoop applications was OpenTSDB – a common-purpose implementation of a distributed, scalable Time Series Database (TSDB) that supported storing, indexing, and serving metrics collected from computer systems (for example, network gear, operating systems, and applications) on a large scale. OpenTSDB then made this data easily accessible and graphable.