What is Hadoop?

Primary tab navigation

What is Hadoop

Apache™ Hadoop® is an open source software project that enables distributed processing of large data sets across clusters of commodity servers. It is designed to scale up from a single server to thousands of machines, with very high degree of fault tolerance. Rather than relying on high-end hardware, the resiliency of these clusters comes from the software's ability to detect and handle failures at the application layer.

Hadoop for the data scientist

IBM BigInsights offers data scientists in-Hadoop analytics, faster time to value, and one secure environment.

Learn more about how Hadoop supports Data Scientists


Hadoop for the Enterprise from IBM

IBM BigInsights brings the power of Hadoop to the enterprise, enhancing Hadoop by adding administrative, discovery, development, provisioning, security and support, along with best-in-class analytical capabilities. IBM® BigInsights™ for Apache™ Hadoop® is a complete solution for large-scale analytics.

Learn about Hadoop for the Enterprise

Why use Hadoop?

Hadoop changes the economics and the dynamics of large-scale computing. Its impact can be boiled down to four salient characteristics.

Hadoop enables a computing solution that is:


A cluster can be expanded by adding new servers or resources without having to move, reformat, or change the dependent analytic workflows or applications.

Cost effective

Hadoop brings massively parallel computing to commodity servers. The result is a sizeable decrease in the cost per terabyte of storage, which in turn makes it affordable to model all your data.


Hadoop is schema-less and can absorb any type of data, structured or not, from any number of sources. Data from multiple sources can be joined and aggregated in arbitrary ways enabling deeper analyses than any one system can provide.

Fault tolerant

When you lose a node, the system redirects work to another location of the data and continues processing without missing a beat.


Hadoop architecture

Hadoop is composed of four core components—Hadoop Common, Hadoop Distributed File System (HDFS), MapReduce and YARN.

Hadoop Common

A module containing the utilities that support the other Hadoop components.


A framework for writing applications that process large amounts of structured and unstructured data in parallel across a cluster of thousands of machines, in a reliable, fault-tolerant manner.

What is MapReduce?


A file system that provides reliable data storage and access across all the nodes in a Hadoop cluster. It links together the file systems on many local nodes to create a single file system.

What is HDFS?

Yet Another Resource Negotiator (YARN)

The next-generation MapReduce, which assigns CPU, memory and storage to applications running on a Hadoop cluster. It enables application frameworks other than MapReduce to run on Hadoop, opening up a wealth of possibilities.

Hadoop is supplemented by an ecosystem of Apache open-source projects that extend the value of Hadoop and improve its usability.


Data access projects


A programming language designed to handle any type of data, helping users to focus more on analyzing large data sets and less on writing map programs and reduce programs.

What is Pig?


A Hadoop runtime component that allows those fluent with SQL to write Hive Query Language (HQL) statements, which are similar to SQL statements. These are broken down into MapReduce jobs and executed across the cluster.

What is Hive?


A distributed, reliable and available service for efficiently collecting, aggregating and moving large amounts of log data. Its main goal is to deliver data from applications to the HDFS.

What is Flume?


A table and storage management service for Hadoop data that presents a table abstraction so the user does not need to know where or how the data is stored.


An Apache open source project that provides data serialization and data exchange services for Hadoop.

What is Avro?


An open-source cluster computing framework with in-memory analytics performance that is up to 100 times faster than MapReduce, depending on the application.


An ELT tool to support the transfer of data between Hadoop and structured data sources.


A column-oriented non-relational (noSQL) database that runs on top of HDFS and is often used for sparse data sets.

What is HBase?


Search projects


An enterprise search tool from the Apache Lucene project that offers powerful search capabilities, including hit highlighting, as well as indexing capabilities, reliability and scalability, a central configuration system, and failover and recovery.


Administration and security projects


A network authentication protocol that works on the basis of “tickets” to allow nodes communicating over a non-secure network to prove their identity to one another in a secure manner.


A centralized infrastructure and set of services that enable synchronization across a cluster.

What is Zookeeper?


A management application that simplifies workflow and coordination between MapReduce jobs.

What is Oozie?

Get started with Hadoop for the Enterprise