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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:
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
