CDP (Big Data Hadoop Administrator) 2

Question 1

Which HDFS configuration parameter controls the minimum percentage of DataNodes that must successfully write a block before the client receives acknowledgment?

Accepted Answer

dfs.replication.min

Answer

dfs.replication.min sets the minimum number of replicas that must be written before the write is considered successful.

Question 2

In YARN, what is the role of the ApplicationMaster?

Accepted Answer

Negotiating resources and tracking task status for a specific application

Answer

The ApplicationMaster is a per-application process that negotiates resources from the ResourceManager and works with NodeManagers to execute tasks.

Question 3

Which command correctly increases the replication factor of an existing HDFS file to 5?

Accepted Answer

hdfs dfs -setrep -w 5 /path/to/file

Answer

The hdfs dfs -setrep command changes the replication factor; -w waits for the replication to complete.

Question 4

A Hadoop cluster has frequent 'GC overhead limit exceeded' errors on the NameNode. What is the most appropriate first corrective action?

Accepted Answer

Increase heap memory allocated to the NameNode via HADOOP_NAMENODE_OPTS

Answer

GC overhead errors on the NameNode indicate insufficient heap memory; increasing it via HADOOP_NAMENODE_OPTS is the direct fix.

Question 5

What does the 'safe mode' state in HDFS prevent?

Accepted Answer

Any modifications to the file system namespace

Answer

In safe mode the NameNode is read-only; it does not allow any modifications to the HDFS namespace.

CDP - Certified Data Professional Practice Test

CDP - Certified Data Professional Practice Test

CDP (Big Data Hadoop Administrator) 2