Cloudera CCAH CCA-505 Questions & Answers

• Question 11:

  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. No new nodes can be added to the cluster until you specify them in the dfs.hosts file

  B. Presented with a blank dfs.hosts property, the NameNode will permit DatNode specified in mapred.hosts to join the cluster

  C. Any machine running the DataNode daemon can immediately join the cluster

  D. The NameNode will update the dfs.hosts property to include machine running DataNode daemon on the next NameNode reboot or with the command dfsadmin -refreshNodes

  Correct Answer: C

• Question 12:

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

  has the following configuration:

  yarn.nodemanager.resource.memory-mb

  32768

  yarn.nodemanager.resource.cpu-vcores

  23

  You want YARN to launch no more than 16 containers per node. What should you do?

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

  B. Modify yarn-site.xml with the following property: yarn.nodemanager.resource.cpu-vcores 16

  C. Modify yarn-site.xml with the following property: yarn.scheduler.minimum-allocation-mb 2048

  D. Modify yarn-site.xml with the following property: yarn.scheduler.minimum-allocation-mb 4096

  Correct Answer: B

• Question 13:

  Which is the default scheduler in YARN?

  A. Fair Scheduler

  B. FIFO Scheduler

  C. Capacity Scheduler

  D. YARN doesn't configure a default scheduler. You must first assign a appropriate scheduler class in yarn-site.xml

  Correct Answer: C

• Question 14:

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

  A. Delete the /swapfile file on the node

  B. Set vm.swappiness to o in /etc/sysctl.conf

  C. Set the ram.swap parameter to o in core-site.xml

  D. Delete the /etc/swap file on the node

  E. Delete the /dev/vmswap file on the node

  Correct Answer: B

• Question 15:

  You observe 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 100 MB. How would you tune your io.sort.mb value to achieve maximum memory to disk I/O ratio?

  A. Decrease the io.sort.mb value to 0

  B. Increase the io.sort.mb to 1GB

  C. For 1GB child heap size an io.sort.mb of 128 MB will always maximize memory to disk I/O

  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

  Correct Answer: D

• Question 16:

  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?

  A. When job A gets submitted, it consumes all the tasks slots.

  B. When job A gets submitted, it doesn't consume all the task slots

  C. When job B gets submitted, Job A has to finish first, before job B can scheduled

  D. When job B gets submitted, it will get assigned tasks, while Job A continue to run with fewer tasks.

  Correct Answer: C

• Question 17:

  Which YARN process runs as "controller O" of a submitted job and is responsible for resource requests?

  A. ResourceManager

  B. NodeManager

  C. JobHistoryServer

  D. ApplicationMaster

  E. JobTracker

  F. ApplicationManager

  Correct Answer: D

• Question 18:

  Your Hadoop cluster is configured with HDFS and MapReduce version 2 (MRv2) on YARN. Can you configure a worker node to run a NodeManager daemon but not a DataNode daemon and still have a function cluster?

  A. Yes. The daemon will receive data from the NameNode to run Map tasks

  B. Yes. The daemon will get data from another (non-local) DataNode to run Map tasks

  C. Yes. The daemon will receive Reduce tasks only

  Correct Answer: A

• Question 19:

  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 becomes the standby NameNode and nn01 becomes the active NameNode

  B. nn02 is fenced, and nn01 becomes the active NameNode

  C. nn01 becomes the standby NamNode and nn02 becomes the active NAmeNode

  D. nn01 is fenced, and nn02 becomes the active NameNode

  Correct Answer: D

• Question 20:

  You want to understand more about how users browse you 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 logs into your Hadoop cluster for 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. Import all users clicks from your OLTP databases into Hadoop using Sqoop

  D. Write a MApReduce job with the web servers from mappers and the Hadoop cluster nodes reducers

  E. Channel these clickstream into Hadoop using Hadoop Streaming

  Correct Answer: AB