Renewal CCA-500 Testing Material 2021

NEW QUESTION 1
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 2
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 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
Your Hadoop cluster contains nodes in three racks. You have not configured the dfs.hosts property in the NameNode’s configuration file. What results?

• A. The NameNode will update the dfs.hosts property to include machines running the DataNode daemon on the next NameNode reboot or with the command dfsadmin–refreshNodes
• B. No new nodes can be added to the cluster until you specify them in the dfs.hosts file
• C. Any machine running the DataNode daemon can immediately join the cluster
• D. Presented with a blank dfs.hosts property, the NameNode will permit DataNodes specified in mapred.hosts to join the cluster

Answer: C

NEW QUESTION 5
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 6
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 7
You want to understand more about how users browse your public website. For example, you want to know which pages they visit prior to placing an order. You have a server farm of 200 web servers hosting your website. Which is the most efficient process to gather these web server across logs into your Hadoop cluster analysis?

• A. Sample the web server logs web servers and copy them into HDFS using curl
• B. Ingest the server web logs into HDFS using Flume
• C. Channel these clickstreams into Hadoop using Hadoop Streaming
• D. Import all user clicks from your OLTP databases into Hadoop using Sqoop
• E. Write a MapReeeduce job with the web servers for mappers and the Hadoop cluster nodes for reducers

Answer: B

Explanation:
Apache Flume is a service for streaming logs into Hadoop.
Apache Flume is a distributed, reliable, and available service for efficiently collecting, aggregating, and moving large amounts of streaming data into the Hadoop Distributed File System (HDFS). It has a simple and flexible architecture based on streaming data flows; and is robust and fault tolerant with tunable reliability mechanisms for failover and recovery.

NEW QUESTION 8
You are running a Hadoop cluster with a NameNode on host mynamenode, a secondary NameNode on host mysecondarynamenode and several DataNodes.
Which best describes how you determine when the last checkpoint happened?

• A. Execute hdfs namenode –report on the command line and look at the Last Checkpoint information
• B. Execute hdfs dfsadmin –saveNamespace on the command line which returns to you the last checkpoint value in fstime file
• C. Connect to the web UI of the Secondary NameNode (http://mysecondary:50090/) and look at the “Last Checkpoint” information
• D. Connect to the web UI of the NameNode (http://mynamenode:50070) and look at the “Last Checkpoint” information

Answer: C

Explanation:
Reference:https://www.inkling.com/read/hadoop-definitive-guide-tom-white-3rd/chapter- 10/hdfs

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
Given:

You want to clean up this list by removing jobs where the State is KILLED. What command you enter?

• A. Yarn application –refreshJobHistory
• B. Yarn application –kill application_1374638600275_0109
• C. Yarn rmadmin –refreshQueue
• D. Yarn rmadmin –kill application_1374638600275_0109

Answer: B

Explanation:
Reference:http://docs.hortonworks.com/HDPDocuments/HDP2/HDP-2.1-latest/bk_using-apache-hadoop/content/common_mrv2_commands.html

NEW QUESTION 11
Identify two features/issues that YARN is designated to address:(Choose two)

• A. Standardize on a single MapReduce API
• B. Single point of failure in the NameNode
• C. Reduce complexity of the MapReduce APIs
• D. Resource pressure on the JobTracker
• E. Ability to run framework other than MapReduce, such as MPI
• F. HDFS latency

Answer: DE

Explanation:
Reference:http://www.revelytix.com/?q=content/hadoop-ecosystem(YARN, first para)

NEW QUESTION 12
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 13
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 14
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 15
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 16
Your cluster implements HDFS High Availability (HA). Your two NameNodes are named nn01 and nn02. What occurs when you execute the command: hdfs haadmin –failover nn01 nn02?

• A. nn02 is fenced, and nn01 becomes the active NameNode
• B. nn01 is fenced, and nn02 becomes the active NameNode
• C. nn01 becomes the standby NameNode and nn02 becomes the active NameNode
• D. nn02 becomes the standby NameNode and nn01 becomes the active NameNode

Answer: B

Explanation:
failover – initiate a failover between two NameNodes
This subcommand causes a failover from the first provided NameNode to the second. If the first
NameNode is in the Standby state, this command simply transitions the second to the Active statewithout error. If the first NameNode is in the Active state, an attempt will be made to gracefullytransition it to the Standby state. If this fails, the fencing methods (as configured bydfs.ha.fencing.methods) will be attempted in order until one of the methods succeeds. Only afterthis process will the second NameNode be transitioned to the Active state. If no fencing methodsucceeds, the second NameNode will not be transitioned to the Active state, and an error will bereturned.

NEW QUESTION 17
What two processes must you do if you are running a Hadoop cluster with a single NameNode and six DataNodes, and you want to change a configuration parameter so that it affects all six DataNodes.(Choose two)

• A. You must modify the configuration files on the NameNode onl
• B. DataNodes read their configuration from the master nodes
• C. You must modify the configuration files on each of the six SataNodes machines
• D. You don’t need to restart any daemon, as they will pick up changes automatically
• E. You must restart the NameNode daemon to apply the changes to the cluster
• F. You must restart all six DatNode daemon to apply the changes to the cluster

Answer: BD

NEW QUESTION 18
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 19
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?

• A. Hadoop fs –getmerge –R westUsers.txt
• B. Hadoop fs –getemerge westUsers westUsers.txt
• C. Hadoop fs –cp westUsers/* westUsers.txt
• D. Hadoop fs –get westUsers westUsers.txt

Answer: B

NEW QUESTION 20
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 21
Each node in your Hadoop cluster, running YARN, has 64GB memory and 24 cores. Your yarn.site.xml has the following configuration:
<property>
<name>yarn.nodemanager.resource.memory-mb</name>
<value>32768</value>
</property>
<property>
<name>yarn.nodemanager.resource.cpu-vcores</name>
<value>12</value>
</property>
You want YARN to launch no more than 16 containers per node. What should you do?

• A. Modify yarn-site.xml with the following property:<name>yarn.scheduler.minimum-allocation-mb</name><value>2048</value>
• B. Modify yarn-sites.xml with the following property:<name>yarn.scheduler.minimum-allocation-mb</name><value>4096</value>
• C. Modify yarn-site.xml with the following property:<name>yarn.nodemanager.resource.cpu-vccores</name>
• D. No action is needed: YARN’s dynamic resource allocation automatically optimizes the node memory and cores

Answer: A

NEW QUESTION 22
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