Real CCA-500 Study Guides 2021

NEW QUESTION 1
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 2
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 3
You are running a Hadoop cluster with MapReduce version 2 (MRv2) on YARN. You consistently see that MapReduce map tasks on your cluster are running slowly because of excessive garbage collection of JVM, how do you increase JVM heap size property to 3GB to optimize performance?

• A. yarn.application.child.java.opts=-Xsx3072m
• B. yarn.application.child.java.opts=-Xmx3072m
• C. mapreduce.map.java.opts=-Xms3072m
• D. mapreduce.map.java.opts=-Xmx3072m

Answer: C

Explanation: Reference:http://hortonworks.com/blog/how-to-plan-and-configure-yarn-in-hdp-2-0/

NEW QUESTION 4
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?

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

Answer: E

NEW QUESTION 5
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 6
You have a cluster running with a FIFO scheduler enabled. You submit a large job A to the cluster, which you expect to run for one hour. Then, you submit job B to the cluster, which you expect to run a couple of minutes only.
You submit both jobs with the same priority.
Which two best describes how FIFO Scheduler arbitrates the cluster resources for job and its tasks?(Choose two)

• A. Because there is a more than a single job on the cluster, the FIFO Scheduler will enforce a limit on the percentage of resources allocated to a particular job at any given time
• B. Tasks are scheduled on the order of their job submission
• C. The order of execution of job may vary
• D. Given job A and submitted in that order, all tasks from job A are guaranteed to finish before all tasks from job B
• E. The FIFO Scheduler will give, on average, and equal share of the cluster resources over the job lifecycle
• F. The FIFO Scheduler will pass an exception back to the client when Job B is submitted, since all slots on the cluster are use

Answer: AD

NEW QUESTION 7
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 8
You have installed a cluster HDFS and MapReduce version 2 (MRv2) on YARN. You have no dfs.hosts entry(ies) in your hdfs-site.xml configuration file. You configure a new worker node by setting fs.default.name in its configuration files to point to the NameNode on your cluster, and you start the DataNode daemon on that worker node. What do you have to do on the cluster to allow the worker node to join, and start sorting HDFS blocks?

• A. Without creating a dfs.hosts file or making any entries, run the commands hadoop.dfsadmin-refreshModes on the NameNode
• B. Restart the NameNode
• C. Creating a dfs.hosts file on the NameNode, add the worker Node’s name to it, then issue the command hadoop dfsadmin –refresh Nodes = on the Namenode
• D. Nothing; the worker node will automatically join the cluster when NameNode daemon is started

Answer: A

NEW QUESTION 9
You are planning a Hadoop cluster and considering implementing 10 Gigabit Ethernet as the network fabric. Which workloads benefit the most from faster network fabric?

• A. When your workload generates a large amount of output data, significantly larger than the amount of intermediate data
• B. When your workload consumes a large amount of input data, relative to the entire capacity if HDFS
• C. When your workload consists of processor-intensive tasks
• D. When your workload generates a large amount of intermediate data, on the order of the input data itself

Answer: A

NEW QUESTION 10
You are running Hadoop cluster with all monitoring facilities properly configured. Which scenario will go undeselected?

• A. HDFS is almost full
• B. The NameNode goes down
• C. A DataNode is disconnected from the cluster
• D. Map or reduce tasks that are stuck in an infinite loop
• E. MapReduce jobs are causing excessive memory swaps

Answer: B

NEW QUESTION 11
Your cluster is configured with HDFS and MapReduce version 2 (MRv2) on YARN. What is the result when you execute: hadoop jar SampleJar MyClass on a client machine?

• A. SampleJar.Jar is sent to the ApplicationMaster which allocates a container for SampleJar.Jar
• B. Sample.jar is placed in a temporary directory in HDFS
• C. SampleJar.jar is sent directly to the ResourceManager
• D. SampleJar.jar is serialized into an XML file which is submitted to the ApplicatoionMaster

Answer: A

NEW QUESTION 12
Table schemas in Hive are:

• A. Stored as metadata on the NameNode
• B. Stored along with the data in HDFS
• C. Stored in the Metadata
• D. Stored in ZooKeeper

Answer: B

NEW QUESTION 13
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?

• A. 25GB on each hard drive may not be used to store HDFS blocks
• B. 100GB on each hard drive may not be used to store HDFS blocks
• 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
• D. A maximum if 100 GB on each hard drive may be used to store HDFS blocks

Answer: B

NEW QUESTION 14
For each YARN job, the Hadoop framework generates task log file. Where are Hadoop task log files stored?

• A. Cached by the NodeManager managing the job containers, then written to a log directory on the NameNode
• B. Cached in the YARN container running the task, then copied into HDFS on job completion
• C. In HDFS, in the directory of the user who generates the job
• D. On the local disk of the slave mode running the task

Answer: D

NEW QUESTION 15
You observed that the number of spilled records from Map tasks far exceeds the number of map output records. Your child heap size is 1GB and your io.sort.mb value is set to 1000MB. How would you tune your io.sort.mb value to achieve maximum memory to disk I/O ratio?

• A. For a 1GB child heap size an io.sort.mb of 128 MB will always maximize memory to disk I/O
• B. Increase the io.sort.mb to 1GB
• C. Decrease the io.sort.mb value to 0
• D. Tune the io.sort.mb value until you observe that the number of spilled records equals (or is as close to equals) the number of map output records.

Answer: D

NEW QUESTION 16
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