NEW QUESTION 1
Your cluster has the following characteristics:
✑ A rack aware topology is configured and on
✑ Replication is set to 3
✑ Cluster block size is set to 64MB
Which describes the file read process when a client application connects into the cluster and requests a 50MB file?

• A. The client queries the NameNode for the locations of the block, and reads all three copie
• B. The first copy to complete transfer to the client is the one the client reads as part of hadoop’s speculative execution framework.
• C. The client queries the NameNode for the locations of the block, and reads from the first location in the list it receives.
• D. The client queries the NameNode for the locations of the block, and reads from a random location in the list it receives to eliminate network I/O loads by balancing which nodes it retrieves data from any given time.
• E. The client queries the NameNode which retrieves the block from the nearest DataNode to the client then passes that block back to the client.

Answer: B

NEW QUESTION 2
You have recently converted your Hadoop cluster from a MapReduce 1 (MRv1) architecture to MapReduce 2 (MRv2) on YARN architecture. Your developers are accustomed to specifying map and reduce tasks (resource allocation) tasks when they run jobs: A developer wants to know how specify to reduce tasks when a specific job runs. Which method should you tell that developers to implement?

• A. MapReduce version 2 (MRv2) on YARN abstracts resource allocation away from the idea of “tasks” into memory and virtual cores, thus eliminating the need for a developer to specify the number of reduce tasks, and indeed preventing the developer from specifying the number of reduce tasks.
• B. In YARN, resource allocations is a function of megabytes of memory in multiples of 1024m
• C. Thus, they should specify the amount of memory resource they need by executing –D mapreduce-reduces.memory-mb-2048
• D. In YARN, the ApplicationMaster is responsible for requesting the resource required for a specific launc
• E. Thus, executing –D yarn.applicationmaster.reduce.tasks=2 will specify that the ApplicationMaster launch two task contains on the worker nodes.
• F. Developers specify reduce tasks in the exact same way for both MapReduce version 1 (MRv1) and MapReduce version 2 (MRv2) on YAR
• G. Thus, executing –D mapreduce.job.reduces-2 will specify reduce tasks.
• H. In YARN, resource allocation is function of virtual cores specified by the ApplicationManager making requests to the NodeManager where a reduce task is handeled by a single container (and thus a single virtual core). Thus, the developer needs to specify the number of virtual cores to the NodeManager by executing –p yarn.nodemanager.cpu-vcores=2

Answer: D

NEW QUESTION 3
Which is the default scheduler in YARN?

• A. YARN doesn’t configure a default scheduler, you must first assign an appropriate scheduler class in yarn-site.xml
• B. Capacity Scheduler
• C. Fair Scheduler
• D. FIFO Scheduler

Answer: B

Explanation: Reference:http://hadoop.apache.org/docs/r2.4.1/hadoop-yarn/hadoop-yarn-site/CapacityScheduler.html

NEW QUESTION 4
You suspect that your NameNode is incorrectly configured, and is swapping memory to disk. Which Linux commands help you to identify whether swapping is occurring?(Select all that apply)

• A. free
• B. df
• C. memcat
• D. top
• E. jps
• F. vmstat
• G. swapinfo

Answer: ADF

Explanation: Reference:http://www.cyberciti.biz/faq/linux-check-swap-usage-command/

NEW QUESTION 5
You use the hadoop fs –put command to add a file “sales.txt” to HDFS. This file is small enough that it fits into a single block, which is replicated to three nodes in your cluster (with a replicationfactor of 3). One of the nodes holding this file (a single block) fails. How will the cluster handle the replication of file in this situation?

• A. The file will remain under-replicated until the administrator brings that node back online
• B. The cluster will re-replicate the file the next time the system administrator reboots the NameNode daemon (as long as the file’s replication factor doesn’t fall below)
• C. This will be immediately re-replicated and all other HDFS operations on the cluster will halt until the cluster’s replication values are resorted
• D. The file will be re-replicated automatically after the NameNode determines it is under- replicated based on the block reports it receives from the NameNodes

Answer: D

NEW QUESTION 6
Your company stores user profile records in an OLTP databases. You want to join these records with web server logs you have already ingested into the Hadoop file system. What is the best way to obtain and ingest these user records?

• A. Ingest with Hadoop streaming
• B. Ingest using Hive’s IQAD DATA command
• C. Ingest with sqoop import
• D. Ingest with Pig’s LOAD command
• E. Ingest using the HDFS put command

Answer: C

NEW QUESTION 7
Choose three reasons why should you run the HDFS balancer periodically?(Choose three)

• A. To ensure that there is capacity in HDFS for additional data
• B. To ensure that all blocks in the cluster are 128MB in size
• C. To help HDFS deliver consistent performance under heavy loads
• D. To ensure that there is consistent disk utilization across the DataNodes
• E. To improve data locality MapReduce

Answer: CDE

Explanation: http://www.quora.com/Apache-Hadoop/It-is-recommended-that-you-run-the-HDFS-balancer-periodically-Why-Choose-3

NEW QUESTION 8
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)

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

Answer: B

NEW QUESTION 9
You want to node to only swap Hadoop daemon data from RAM to disk when absolutely necessary. What should you do?

• A. Delete the /dev/vmswap file on the node
• B. Delete the /etc/swap file on the node
• C. Set the ram.swap parameter to 0 in core-site.xml
• D. Set vm.swapfile file on the node
• E. Delete the /swapfile file on the node

Answer: D

NEW QUESTION 10
Which two are features of Hadoop’s rack topology?(Choose two)

• A. Configuration of rack awareness is accomplished using a configuration fil
• B. You cannot use a rack topology script.
• C. Hadoop gives preference to intra-rack data transfer in order to conserve bandwidth
• D. Rack location is considered in the HDFS block placement policy
• E. HDFS is rack aware but MapReduce daemon are not
• F. Even for small clusters on a single rack, configuring rack awareness will improve performance

Answer: BC

NEW QUESTION 11
You’re upgrading a Hadoop cluster from HDFS and MapReduce version 1 (MRv1) to one running HDFS and MapReduce version 2 (MRv2) on YARN. You want to set and enforce version 1 (MRv1) to one running HDFS and MapReduce version 2 (MRv2) on YARN. You want to set and enforce a block size of 128MB for all new files written to the cluster after upgrade. What should you do?

• A. You cannot enforce this, since client code can always override this value
• B. Set dfs.block.size to 128M on all the worker nodes, on all client machines, and on the NameNode, and set the parameter to final
• C. Set dfs.block.size to 128 M on all the worker nodes and client machines, and set the parameter to fina
• D. You do not need to set this value on the NameNode
• E. Set dfs.block.size to 134217728 on all the worker nodes, on all client machines, and on the NameNode, and set the parameter to final
• F. Set dfs.block.size to 134217728 on all the worker nodes and client machines, and set the parameter to fina
• G. You do not need to set this value on the NameNode

Answer: C

NEW QUESTION 12
Your cluster is running MapReduce version 2 (MRv2) on YARN. Your ResourceManager is configured to use the FairScheduler. Now you want to configure your scheduler such that a new user on the cluster can submit jobs into their own queue application submission. Which configuration should you set?

• A. You can specify new queue name when user submits a job and new queue can be created dynamically if the property yarn.scheduler.fair.allow-undecleared-pools = true
• B. Yarn.scheduler.fair.user.fair-as-default-queue = false and yarn.scheduler.fair.allow- undecleared-pools = true
• C. You can specify new queue name when user submits a job and new queue can be created dynamically if yarn .schedule.fair.user-as-default-queue = false
• D. You can specify new queue name per application in allocations.xml file and have new jobs automatically assigned to the application queue

Answer: A

NEW QUESTION 13
Which YARN process run as “container 0” of a submitted job and is responsible for resource qrequests?

• A. ApplicationManager
• B. JobTracker
• C. ApplicationMaster
• D. JobHistoryServer
• E. ResoureManager
• F. NodeManager

Answer: C

NEW QUESTION 14
Which command does Hadoop offer to discover missing or corrupt HDFS data?

• A. Hdfs fs –du
• B. Hdfs fsck
• C. Dskchk
• D. The map-only checksum
• E. Hadoop does not provide any tools to discover missing or corrupt data; there is not need because three replicas are kept for each data block

Answer: B

Explanation: Reference:https://twiki.grid.iu.edu/bin/view/Storage/HadoopRecovery

NEW QUESTION 15
On a cluster running CDH 5.0 or above, you use the hadoop fs –put command to write a 300MB file into a previously empty directory using an HDFS block size of 64 MB. Just after this command has finished writing 200 MB of this file, what would another use see when they look in directory?

• A. The directory will appear to be empty until the entire file write is completed on the cluster
• B. They will see the file with a ._COPYING_ extension on its nam
• C. If they view the file, they will see contents of the file up to the last completed block (as each 64MB block is written, that block becomes available)
• D. They will see the file with a ._COPYING_ extension on its nam
• E. If they attempt to view the file, they will get a ConcurrentFileAccessException until the entire file write is completed on the cluster
• F. They will see the file with its original nam
• G. If they attempt to view the file, they will get a ConcurrentFileAccessException until the entire file write is completed on the cluster

Answer: B

NEW QUESTION 16
Which YARN daemon or service monitors a Controller’s per-application resource using (e.g., memory CPU)?

• A. ApplicationMaster
• B. NodeManager
• C. ApplicationManagerService
• D. ResourceManager

Answer: A