HDFS ZooKeeper

HDFS (Hadoop Distributed File System) and ZooKeeper are both critical components in the Hadoop ecosystem, but they serve different purposes and play distinct roles within a Hadoop cluster.

HDFS (Hadoop Distributed File System):

• HDFS is a distributed file system designed to store and manage vast amounts of data across a cluster of commodity hardware.
• It is the primary storage system for Hadoop and is responsible for storing the data that Hadoop applications process.
• HDFS divides large files into smaller blocks and replicates these blocks across multiple data nodes in the cluster to ensure data availability and fault tolerance.
• It is optimized for high-throughput data access and is well-suited for storing and processing large files, such as those used in big data analytics.

ZooKeeper:

• ZooKeeper is a distributed coordination service that provides a centralized and reliable way for distributed applications to coordinate and manage configuration information, maintain synchronization, and handle distributed locks and elections.
• It is often used to manage distributed systems and ensure consistency and coordination among distributed nodes.
• ZooKeeper uses a hierarchical file-like structure called the ZooKeeper tree, where each node (known as a znode) can store a small amount of data.
• Distributed applications can use ZooKeeper to elect a leader, manage configuration information, and coordinate distributed tasks.

While HDFS focuses on distributed storage and is primarily responsible for data storage and retrieval, ZooKeeper focuses on distributed coordination and provides a centralized platform for managing coordination tasks across various components and services in a Hadoop cluster. ZooKeeper is used by many Hadoop ecosystem components (such as HBase, Kafka, and others) to maintain coordination and consensus among distributed nodes.