Apache Hadoop
Apache Hadoop is an open-source software framework for distributed storage and processing of large datasets across clusters of commodity hardware. It consists of two core components: Hadoop Distributed File System (HDFS) for storage and MapReduce for processing, enabling scalable and fault-tolerant big data analytics. On-premise deployment refers to installing and running Hadoop on an organization's own physical servers and infrastructure, rather than in the cloud.
Developers should learn Apache Hadoop on-premise when working with massive datasets (e.g., petabytes) that require batch processing, such as log analysis, data warehousing, or ETL pipelines, especially in industries like finance or healthcare with strict data sovereignty requirements. It's ideal for organizations needing full control over their data and infrastructure, avoiding cloud vendor lock-in, and leveraging existing hardware investments.