What is Apache Hadoop?

An Introduction to Distributed Storage, MapReduce Computation, and Big Data Architecture

Fact-Checked & Reviewed by: Hambirrao P | Updated: June 2026 | Verified Technical Expert

Key Takeaways

  • Splits large datasets across cheap commodity hardware clusters using HDFS.
  • Applies MapReduce to process structured and unstructured data in parallel blocks.
  • Functions as the foundational framework that enabled modern enterprise big data lakes.

Introduction to Apache Hadoop

Apache Hadoop is a collection of open-source software utilities that facilitates using a network of many computers to solve problems involving massive amounts of data and computation. It provides a software framework for distributed storage and processing of big data.

Core Modules: HDFS, YARN, and MapReduce

Hadoop consists of three core components:
1. HDFS (Hadoop Distributed File System): A distributed storage layer that breaks large files into blocks and replicates them across cluster nodes.
2. MapReduce: The software framework that processes large datasets in parallel across nodes.
3. YARN (Yet Another Resource Negotiator): The cluster operating system managing compute resources and job scheduling.

Hadoop in the Era of Cloud Lakes

While modern data pipelines frequently use memory-centric frameworks like Spark or cloud services like Snowflake for processing, Hadoop HDFS remains highly relevant as a cost-effective, high-capacity distributed file system for storing massive historical datasets.

HDFS File Management Shell Operations

# Create a partitioned analytics folder structure on HDFS
hdfs dfs -mkdir -p /analytics/cacts/input

# Transfer local data lake CSV from local machine to Hadoop
hdfs dfs -put client_records.csv /analytics/cacts/input/

# Read files and verify HDFS directory structures
hdfs dfs -ls /analytics/cacts/input/

Official Documentation

Access official code repositories and developer documentation.

Official Apache Hadoop Documentation ↗

Frequently Asked Questions

When does the next 1-to-1 training intake start?

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Intakes start twice monthly on the 1st and 15th. The next upcoming 1-to-1 intake starts on October 1, 2026 (with secondary intake on October 15, 2026).

What is HDFS replication?

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HDFS automatically replicates each data block across three separate node machines by default to ensure data availability in case of server hardware failures.

How does Spark relate to Hadoop?

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Spark is often run on top of Hadoop HDFS to utilize its distributed storage capacity while replacing MapReduce with Spark's faster in-memory processing engine.

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