CCA-500 Online Practice Questions and Answers

Each node in your Hadoop cluster, running YARN, has 64GB memory and 24 cores. Your yarn.site.xml

has the following configuration:

yarn.nodemanager.resource.memory-mb

32768

yarn.nodemanager.resource.cpu-vcores

12

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: yarn.scheduler.minimum-allocation-mb 2048

B. Modify yarn-sites.xml with the following property: yarn.scheduler.minimum-allocation-mb 4096

C. Modify yarn-site.xml with the following property: yarn.nodemanager.resource.cpu-vccores

D. No action is needed: YARN's dynamic resource allocation automatically optimizes the node memory and cores

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

What does CDH packaging do on install to facilitate Kerberos security setup?

A. Automatically configures permissions for log files at and MAPRED_LOG_DIR/userlogs

B. Creates users for hdfs and mapreduce to facilitate role assignment

C. Creates directories for temp, hdfs, and mapreduce with the correct permissions

D. Creates a set of pre-configured Kerberos keytab files and their permissions

E. Creates and configures your kdc with default cluster values

Which YARN daemon or service negotiations map and reduce Containers from the Scheduler, tracking their status and monitoring progress?

A. NodeManager

B. ApplicationMaster

C. ApplicationManager

D. ResourceManager

During the execution of a MapReduce v2 (MRv2) job on YARN, where does the Mapper place the intermediate data of each Map Task?

A. The Mapper stores the intermediate data on the node running the Job's ApplicationMaster so that it is available to YARN ShuffleService before the data is presented to the Reducer

B. The Mapper stores the intermediate data in HDFS on the node where the Map tasks ran in the HDFS / usercache/and(user)/apache/application_and(appid) directory for the user who ran the job

C. The Mapper transfers the intermediate data immediately to the reducers as it is generated by the Map Task

D. YARN holds the intermediate data in the NodeManager's memory (a container) until it is transferred to the Reducer

E. The Mapper stores the intermediate data on the underlying filesystem of the local disk in the directories yarn.nodemanager.locak-DIFS

You are configuring a server running HDFS, MapReduce version 2 (MRv2) on YARN running Linux. How must you format underlying file system of each DataNode?

A. They must be formatted as HDFS

B. They must be formatted as either ext3 or ext4

C. They may be formatted in any Linux file system

D. They must not be formatted - - HDFS will format the file system automatically

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 copies. The first copy to complete transfer to the client is the one the client reads as part of hadoop's speculative execution framework.

B. The client queries the NameNode for the locations of the block, and reads from the first location in the list it receives.

C. 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.

D. The client queries the NameNode which retrieves the block from the nearest DataNode to the client then passes that block back to the client.

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

In CDH4 and later, which file contains a serialized form of all the directory and files inodes in the filesystem, giving the NameNode a persistent checkpoint of the filesystem metadata?

A. fstime

B. VERSION

C. Fsimage_N (where N reflects transactions up to transaction ID N)

D. Edits_N-M (where N-M transactions between transaction ID N and transaction ID N)

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