Hadoop Zookeeper Quiz - MCQ Questions and Answers

Introduction

Welcome to the Hadoop Zookeeper Quiz! This quiz is designed to help you test your basic understanding of Zookeeper, a key component of the Hadoop ecosystem. Zookeeper is a centralized service for maintaining configuration information, naming, providing distributed synchronization, and providing group services. These questions are aimed at beginners and will cover fundamental concepts and functionalities of Zookeeper.

1. What is Apache Zookeeper primarily used for?

a) Data storage

b) Managing distributed applications

c) Data querying

d) Web hosting

Answer:

b) Managing distributed applications

Explanation:

Zookeeper is primarily used for managing distributed applications by providing a centralized service for maintaining configuration information, naming, and providing distributed synchronization.

2. What is the primary data structure used in Zookeeper?

a) Tree

b) Linked List

c) Graph

d) Queue

Answer:

a) Tree

Explanation:

Zookeeper organizes its data in a hierarchical structure similar to a file system, called a tree structure.

3. In Zookeeper, what is a ZNode?

a) A data node

b) A configuration file

c) A client connection

d) A data structure

Answer:

a) A data node

Explanation:

A ZNode is a data node in Zookeeper’s hierarchical namespace, similar to a file in a file system.

4. Which of the following is not a Zookeeper feature?

a) High availability

b) Leader election

c) Distributed lock

d) Data replication

Answer:

d) Data replication

Explanation:

Zookeeper provides high availability, leader election, and distributed locks, but it is not designed for data replication in the traditional sense used by databases.

5. What is the role of the Zookeeper ensemble?

a) To store data

b) To execute client requests

c) To coordinate distributed systems

d) To provide a user interface

Answer:

c) To coordinate distributed systems

Explanation:

A Zookeeper ensemble is a group of Zookeeper servers that work together to coordinate distributed systems, ensuring consistency and reliability.

6. Which of the following is a key benefit of using Zookeeper?

a) Simplified distributed system management

b) Increased data storage capacity

c) Faster data processing

d) Enhanced network security

Answer:

a) Simplified distributed system management

Explanation:

Zookeeper simplifies the management of distributed systems by providing services such as configuration management, naming, and synchronization.

7. What is the default port on which Zookeeper listens?

a) 8080

b) 2181

c) 3306

d) 5432

Answer:

b) 2181

Explanation:

By default, Zookeeper listens on port 2181 for client connections.

8. Which of the following is a type of ZNode?

a) Persistent ZNode

b) Temporary ZNode

c) Sequential ZNode

d) All of the above

Answer:

d) All of the above

Explanation:

Zookeeper supports various types of ZNodes, including persistent, temporary, and sequential ZNodes.

9. What does the "watcher" mechanism in Zookeeper do?

a) Monitors data changes

b) Executes commands

c) Manages network traffic

d) Stores logs

Answer:

a) Monitors data changes

Explanation:

The watcher mechanism in Zookeeper allows clients to get notifications of changes to ZNodes they are interested in.

10. In Zookeeper, what is an ephemeral node?

a) A node that persists after the client disconnects

b) A node that is automatically deleted when the client disconnects

c) A node that stores client data permanently

d) A node used for storing configurations

Answer:

b) A node that is automatically deleted when the client disconnects

Explanation:

An ephemeral node in Zookeeper is automatically deleted when the client that created it disconnects.

11. What is a Zookeeper quorum?

a) The majority of servers required to perform an operation

b) The total number of servers in a cluster

c) A group of client connections

d) A data backup

Answer:

a) The majority of servers required to perform an operation

Explanation:

A quorum in Zookeeper is the minimum number of servers that must agree for an operation to proceed.

12. What does the Leader in a Zookeeper ensemble do?

a) Executes all write operations

b) Reads data from clients

c) Coordinates between clients

d) Monitors network traffic

Answer:

a) Executes all write operations

Explanation:

The Leader in a Zookeeper ensemble is responsible for executing all write operations and ensuring consistency across the ensemble.

13. How does Zookeeper handle concurrent access?

a) Through data replication

b) By using locks and synchronization

c) By queueing requests

d) By denying concurrent access

Answer:

b) By using locks and synchronization

Explanation:

Zookeeper handles concurrent access by providing locks and synchronization mechanisms, ensuring that only one client can perform certain operations at a time.

14. In Zookeeper, what is the purpose of the "session timeout"?

a) To end a client session after a fixed time

b) To define how long a client can be inactive before being disconnected

c) To determine the lifespan of a ZNode

d) To set the time limit for data replication

Answer:

b) To define how long a client can be inactive before being disconnected

Explanation:

The session timeout in Zookeeper determines how long a client can be inactive before it is considered disconnected, which can lead to the deletion of ephemeral nodes created by the client.

15. What happens if the Leader in a Zookeeper ensemble fails?

a) The entire system shuts down

b) A new Leader is automatically elected

c) All nodes become Leaders

d) No new write operations can be performed

Answer:

b) A new Leader is automatically elected

Explanation:

If the Leader in a Zookeeper ensemble fails, a new Leader is automatically elected from the remaining servers to continue operations.

16. What command is used to start a Zookeeper server?

a) zkServer.sh start

b) zk.sh start

c) startZK.sh

d) zkServerStart

Answer:

a) zkServer.sh start

Explanation:

The command to start a Zookeeper server is `zkServer.sh start`.

17. What is the default data directory for Zookeeper?

a) /var/lib/zookeeper

b) /usr/local/zookeeper/data

c) /opt/zookeeper/data

d) /zookeeper_data

Answer:

a) /var/lib/zookeeper

Explanation:

By default, Zookeeper stores its data in the directory `/var/lib/zookeeper`.

18. What is a "follower" in Zookeeper?

a) A client that connects to the server

b) A server that replicates data from the leader

c) A secondary storage node

d) A backup server

Answer:

b) A server that replicates data from the leader

Explanation:

In Zookeeper, a follower is a server that replicates data from the leader and helps in ensuring data consistency.

19. Which of the following is a correct Zookeeper client operation?

a) getZNode

b) createZNode

c) readZNode

d) getData

Answer:

d) getData

Explanation:

The `getData` operation is used by Zookeeper clients to retrieve data stored in a specific ZNode.

20. What is the purpose of the "tickTime" parameter in Zookeeper configuration?

a) It defines the interval for client heartbeats

b) It sets the data backup frequency

c) It configures the session timeout

d) It determines the leader election timeout

Answer:

a) It defines the interval for client heartbeats

Explanation:

The "tickTime" parameter in the Zookeeper configuration specifies the interval (in milliseconds) for client heartbeats, which helps detect client failures.

Conclusion

You have completed the Hadoop Zookeeper Quiz! These beginner-level questions covered key concepts, operations, and configurations of Zookeeper, providing you with a foundational understanding. Mastering these basics will enable you to work more effectively with Zookeeper in managing distributed systems. Keep practicing and exploring more advanced topics to deepen your knowledge.