Databricks Certified Associate Developer For Apache Spark 30 · Free Practice Question Easy
Question 9
- A Worker nodes are the most granular level of execution in the Spark execution hierarchy.
- B Worker nodes always have a one-to-one relationship with executors.
- C Worker nodes are the nodes of a cluster that perform computations.
- D Worker nodes are synonymous with executors.
Reveal correct answer
Correct answer: C
Explanation
The role of worker nodes/executors:
1. Perform the data processing for the application code
2. Read from and write the data to the external sources
3. Store the computation results in memory, or disk.
The executors run throughout the lifetime of the Spark application. This is a static allocation of executors. The user can also decide how many numbers of executors are required to run the tasks, depending on the workload. This is a dynamic allocation of executors.
Before the execution of tasks, the executors are registered with the driver program through the cluster manager, so that the driver knows how many numbers of executors are running to perform the scheduled tasks. The executors then start executing the tasks scheduled by the worker nodes through the cluster manager.
Whenever any of the worker nodes fail, the tasks that are required to be performed will be automatically allocated to any other worker nodes
Discussion
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