The ____ command in HDFS is used to add or remove data nodes dynamically.

  • hdfs datanodeadmin
  • hdfs dfsadmin
  • hdfs nodecontrol
  • hdfs nodemanage
The hdfs dfsadmin command in HDFS is used to add or remove data nodes dynamically. It provides administrative functions for managing the Hadoop Distributed File System, including the addition or decommissioning of data nodes.

____ in Hadoop clusters helps in identifying bottlenecks and optimizing resource allocation.

  • HDFS
  • MapReduce
  • Spark
  • YARN
YARN (Yet Another Resource Negotiator) in Hadoop clusters helps in identifying bottlenecks and optimizing resource allocation. It manages and allocates resources efficiently, allowing various applications to run simultaneously on the cluster.

Advanced Hadoop performance tuning often involves adjusting the ____ threshold for task JVM reuse.

  • Buffer Size
  • Cache Size
  • Garbage Collection
  • Serialization
In advanced Hadoop performance tuning, adjusting the Garbage Collection threshold for task JVM reuse is crucial. Garbage Collection helps manage memory and reclaim unused resources, impacting the overall performance of Hadoop tasks. Tweaking this threshold can optimize resource utilization.

____ is a tool in Hadoop used for diagnosing network topology and speed between nodes in HDFS.

  • DataNode
  • Hadoop Diagnostics Tool (HDT)
  • NameNode
  • ResourceManager
The Hadoop Diagnostics Tool (HDT) is used for diagnosing network topology and speed between nodes in HDFS. It helps administrators identify potential issues related to network performance and data transfer within the Hadoop cluster.

Oozie workflows are based on which type of programming model?

  • Declarative Programming
  • Functional Programming
  • Object-Oriented Programming
  • Procedural Programming
Oozie workflows are based on a declarative programming model. In a declarative approach, users specify what needs to be done and define the desired state, and Oozie takes care of coordinating the execution of tasks to achieve that state.

Which language is primarily used for writing MapReduce jobs in Hadoop's native implementation?

  • C++
  • Java
  • Python
  • Scala
Java is primarily used for writing MapReduce jobs in Hadoop's native implementation. Hadoop's MapReduce framework is implemented in Java, making it the language of choice for developing MapReduce applications in the Hadoop ecosystem.

In Hadoop, what is the impact of the heartbeat signal between DataNode and NameNode?

  • Data Block Replication
  • DataNode Health Check
  • Job Scheduling
  • Load Balancing
The heartbeat signal between DataNode and NameNode serves as a health check for DataNodes. It allows the NameNode to verify the availability and health status of each DataNode in the cluster. If a DataNode fails to send a heartbeat within a specified time, it is considered dead or unreachable, and the NameNode initiates the block replication process to maintain data availability.

In MapReduce, the ____ phase involves sorting and merging the intermediate data from mappers.

  • Combine
  • Merge
  • Partition
  • Shuffle
In MapReduce, the Shuffle phase involves sorting and merging the intermediate data from mappers before sending it to the Reducer. This phase is critical for optimizing data transfer and reducing network overhead.

When debugging a Hadoop application, what is the significance of examining the first few lines of a task's log file?

  • Analyze Output Data
  • Diagnose Task Failures
  • Identify Input Data Issues
  • Understand Resource Utilization
Examining the first few lines of a task's log file is significant in debugging a Hadoop application as it helps diagnose task failures. The log provides valuable information about the execution context, errors, and exceptions encountered during the task, aiding developers in identifying and resolving issues.

Oozie workflows can be optimized using ____ for effective resource utilization and scheduling.

  • Capacity Scheduler
  • Fair Scheduler
  • Coordination
  • Oozie CLI (Command Line Interface)
The correct option is 'Coordination.' Oozie workflows can be optimized using coordination for effective resource utilization and scheduling. Coordination allows for better synchronization and control of job execution, ensuring that dependencies are met before starting subsequent jobs.