Developing Distributed Applications Using ZooKeeper Cognitive Class Exam Quiz Answers

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Enroll Here: Developing Distributed Applications Using ZooKeeper Cognitive Class Exam Quiz Answers

Developing Distributed Applications Using ZooKeeper Cognitive Class Certification Answers

Module 1 – Introduction Zookeeper Quiz Answers – Cognitive Class

Question 1: What is NOT a benefit that distributed systems offer over centralized systems?

• Price to achieve redundancy
• Redundancy
• Ease of developing your own coordination service
• Scalability

Question 2: A ZooKeeper client can perform a read operation from any server in the ensemble, but a write operation must go through the ZooKeeper leader and requires a majority consensus to succeed. True or false?

• False
• True

Question 3: What’s the benefit of running ZooKeeper in Standalone mode over Replicated mode?

• Cheaper
• Resilience
• Simpler testing and learning
• High availability

Module 2 – The Zoookeeper Data Model Quiz Answers – Cognitive Class

Question 1: Which of the following statements is true?

• A client reading the data stored at a znode can receive some of the data.
• ZooKeeper is designed for high-volume storage.
• The path to a znode must be expressed as a canonical, absolute, and slash-separated path.
• Znodes can be used to store data that exceeds 1MB.

Question 2: A znode can be in multiple states at the same time. True or false?

• False
• True

Question 3: Which of the following commands is used to retrieve the access control list of a znode?

• fetchACL
• setACL
• printACL
• getACL

Module 3 – Programming and Advance Topics Quiz Answers – Cognitive Class

Question 1: In addition to the 4 letter commands, JMX can be used to monitor ZooKeeper. True or false?

• False
• True

Question 2: Which two authentication plugins are included with ZooKeeper?

• ip and MD5
• ip and identify
• digset and MD5
• ip and digest

Question 3: What are the bindings that ZooKeeper comes with out of the box?

• Ruby and Java
• Java and C#
• Python and C
• Java and C

Developing Distributed Applications Using ZooKeeper Final Exam Answers – Cognitive Class

Question 1: What is the primary purpose of ZooKeeper in the Hadoop architecture?

• To provide logging support for Hadoop jobs
• To support the execution of workflows consisting of a collection of actions
• To provide a centralized coordination service for distributed applications
• To move data into HDFS

Question 2: When executing ZooKeeper in Replicated mode, a new leader can be elected if the former leader fails. True or false?

• True
• False

Question 3: Which of the following are consistency guarantees made by ZooKeeper? Select all that apply.

• Atomicity
• Reliability
• Timeliness
• Release

Question 4: ZooKeeper guarantees simultaneously consistent cross-client views. True or false?

• True
• False

Question 5: ZooKeeper can be used to implement several use cases including

• Leader Election
• Queue Management
• Configuration Management
• Locking
• All of the above

Question 6: A ZooKeeper client can maintain a list of servers to connect to, and the client will go through its list until it successfully connects to a ZooKeeper server. True or false?

• True
• False

Question 7: ZooKeeper Watches can be used to

• Watch for failed MapReduce jobs
• Watch for changes to Hadoop configuration
• Watch for changes in the Hadoop Filesystem (HDFS)
• None of the above

Question 8: If you want to be notified of a change in a ZooKeeper znode, you should use

• The ZooKeeper getData() method
• The ZooKeeper sync() method
• The ZooKeeper callback() method
• A ZooKeeper Watch

Question 9: In ZooKeeper, if you want a znode to be deleted when the client session ends, you should create a

• Session znode
• Ephemeral znode
• Temp znode
• Persistent znode

Question 10: Using the –s parameter when creating a znode results in a

• Ephemeral znode
• Sequential znode
• Temp znode
• Session znode
• Persistent znode

Question 11: Which of the ‘four letter word’ commands will show you the status of a ZooKeeper server?

• stat
• dump
• conf
• cons
• ruok

Question 12: When using the ZooKeeper Java API, what do you need to implement in order to receive Watcher notifications?

• A constructor that calls the watch method
• A class that inherits from zNode
• The process method of the Watcher interface
• None of the above

Question 13: In ZooKeeper, setting an ACL only pertains to the specific znode and is not recursive. True or false?

• True
• False

Question 14: In ZooKeeper, what permission do you need to have in order to change the ACL on a znode?

• READ
• ADMIN
• WRITE
• DELETE
• CREATE

Question 15: You can plug in your own authentication scheme rather than using the ones provided out of the box by ZooKeeper. True or false?

• True
• False

Introduction to Developing Distributed Applications Using ZooKeeper

ZooKeeper is a distributed coordination service widely used in distributed applications to manage and synchronize processes across a cluster of machines. It provides a reliable and efficient way to coordinate distributed systems, ensuring consistency and synchronization between nodes.

Here’s an introductory overview of developing distributed applications using ZooKeeper:

1. Understanding ZooKeeper’s Role:
   • ZooKeeper acts as a centralized repository for configuration information, naming, synchronization, and group services in distributed systems.
   • It maintains a hierarchical namespace called znodes, similar to a file system, where data can be stored and accessed by clients.
   • Its primary goal is to provide a robust coordination service that enables distributed processes to agree on a shared state.
2. Key Concepts:
   • Znodes: These are the fundamental data nodes in ZooKeeper’s hierarchical namespace. Znodes can represent various aspects of a distributed system, such as configuration, locks, or synchronization points.
   • Watchers: Clients can set watches on znodes to receive notifications about changes in the znode’s state. This mechanism enables event-driven communication between clients and ZooKeeper.
   • Sessions: Clients interact with ZooKeeper through sessions, which represent their connection to the service. Sessions can time out if there’s no activity, and clients need to handle session expiration gracefully.
3. Use Cases:
   • Configuration Management: Store configuration data in ZooKeeper, allowing distributed applications to dynamically retrieve and update configurations as needed.
   • Distributed Locks: Use ZooKeeper to implement distributed locks, ensuring mutual exclusion among processes across multiple machines.
   • Leader Election: ZooKeeper can be utilized to elect a leader among a group of distributed nodes, facilitating fault tolerance and load balancing.
   • Service Discovery: Maintain a registry of available services and their locations using ZooKeeper, enabling clients to discover and connect to services dynamically.
4. Development Process:
   • Client Libraries: ZooKeeper provides client libraries for various programming languages, such as Java, Python, and others, making it accessible to developers working in different environments.
   • API Usage: Developers interact with ZooKeeper through its API, which provides methods for creating, reading, updating, and deleting znodes, as well as setting watches and managing sessions.
   • Error Handling: It’s essential to handle errors gracefully when working with ZooKeeper, as network partitions, timeouts, and other issues can occur in distributed environments.
5. Best Practices:
   • Keep Znode Sizes Small: Large znodes can impact ZooKeeper’s performance. It’s recommended to keep znode sizes small, especially for frequently accessed data.
   • Use Watches Wisely: While watches are useful for event-driven programming, excessive use of watches can lead to performance issues. Use them judiciously.
   • Handle Session Expiration: Implement session expiration handling to gracefully recover from session timeouts and reestablish connections with ZooKeeper.
6. Testing and Deployment:
   • Unit Testing: Write unit tests to validate the functionality of your ZooKeeper interactions, mocking the ZooKeeper server if necessary.
   • Integration Testing: Test your distributed application in a simulated environment to ensure that it behaves as expected under real-world conditions.
   • Deployment Considerations: ZooKeeper should be deployed in a highly available and fault-tolerant manner to ensure the reliability of your distributed systems.

By understanding these concepts and following best practices, developers can effectively leverage ZooKeeper to build robust and scalable distributed applications.