CCA-500 Free Practice Test

A slave node in your cluster has 4 TB hard drives installed (4 x 2TB). The DataNode is configured to store HDFS blocks on all disks. You set the value of the dfs.datanode.du.reserved parameter to 100 GB. How does this alter HDFS block storage?

1. A. 25GB on each hard drive may not be used to store HDFS blocks
2. B. 100GB on each hard drive may not be used to store HDFS blocks
3. C. All hard drives may be used to store HDFS blocks as long as at least 100 GB in total is available on the node
4. D. A maximum if 100 GB on each hard drive may be used to store HDFS blocks

Correct Answer: B

You have a cluster running with the fair Scheduler enabled. There are currently no jobs running on the cluster, and you submit a job A, so that only job A is running on the cluster. A while later, you submit Job B. now Job A and Job B are running on the cluster at the same time. How will the Fair Scheduler handle these two jobs?(Choose two)

1. A. When Job B gets submitted, it will get assigned tasks, while job A continues to run with fewer tasks.
2. B. When Job B gets submitted, Job A has to finish first, before job B can gets scheduled.
3. C. When Job A gets submitted, it doesn’t consumes all the task slots.
4. D. When Job A gets submitted, it consumes all the task slots.

Correct Answer: B

On a cluster running MapReduce v2 (MRv2) on YARN, a MapReduce job is given a directory of 10 plain text files as its input directory. Each file is made up of 3 HDFS blocks. How many Mappers will run?

1. A. We cannot say; the number of Mappers is determined by the ResourceManager
2. B. We cannot say; the number of Mappers is determined by the developer
3. C. 30
4. D. 3
5. E. 10
6. F. We cannot say; the number of mappers is determined by the ApplicationMaster

Correct Answer: E

Which scheduler would you deploy to ensure that your cluster allows short jobs to finish within a reasonable time without starting long-running jobs?

1. A. Complexity Fair Scheduler (CFS)
2. B. Capacity Scheduler
3. C. Fair Scheduler
4. D. FIFO Scheduler

Correct Answer: C
Reference:http://hadoop.apache.org/docs/r1.2.1/fair_scheduler.html

You have just run a MapReduce job to filter user messages to only those of a selected geographical region. The output for this job is in a directory named westUsers, located just below your home directory in HDFS. Which command gathers these into a single file on your local file system?

1. A. Hadoop fs –getmerge –R westUsers.txt
2. B. Hadoop fs –getemerge westUsers westUsers.txt
3. C. Hadoop fs –cp westUsers/* westUsers.txt
4. D. Hadoop fs –get westUsers westUsers.txt

Correct Answer: B