Hadoop Online Quiz

Q 1 - In a Hadoop cluster, what is true for a HDFS block that is no longer available due to disk corruption or machine failure?

A - It is lost for ever

B - It can be replicated form its alternative locations to other live machines.

C - The namenode allows new client request to keep trying to read it.

D - The Mapreduce job process runs ignoring the block and the data stored in it.

Q 2 - Zookeeper ensures that

A - All the namenodes are actively serving the client requests

B - Only one namenode is actively serving the client requests

C - A failover is triggered when any of the datanode fails.

D - A failover can not be started by hadoop administrator.

Q 3 - Which of the following is not a fencing mechanism for a previously active namenode?

A - Disabling its network port via a remote management command.

B - Revoking its access to shared storage directory.

C - Formatting its disk drive.

D - STONITH

Q 4 - The file in Namenode which stores the information mapping the data block location with file name is −

A - dfsimage

B - nameimage

C - fsimage

D - image

Q 5 - The Zookeeper

A - Detects the failure of the namenode and elects a new namenode.

B - Detects the failure of datanodes and elects a new datanode.

C - Prevents the hardware from overheating by shutting them down.

D - Maintains a list of all the components IP address of the Hadoop cluster.

Q 6 - The inter process communication between different nodes in Hadoop uses

A - REST API

B - RPC

C - RMI

D - IP Exchange

Q 7 - The archive file created in Hadoop always has the extension of

A - .hrc

B - .har

C - .hrh

D - .hrar

Q 8 - The namenode loses its only copy of fsimage file. We can recover this from

A - Datanodes

B - Secondary namenode

C - Checkpoint node

D - Never

Q 9 - When archiving Hadoop files, which of the following statements are true? (Choose two answers)

1. Archived files will display with the extension .arc.

2. Many small files will become fewer large files.

3. MapReduce processes the original files names even after files are archived.

4. Archived files must be UN archived for HDFS and MapReduce to access the original, small files.

5. Archive is intended for files that need to be saved but no longer accessed by HDFS.

A - 1 & 3

B - 2 & 3

C - 2 & 4

D - 3 & 4

Q 10 - The org.apache.hadoop.io.Writable interface declares which two methods? (Choose 2 answers.)

1. public void readFields(DataInput).

2. public void read(DataInput).

3. public void writeFields(DataOutput).

4. public void write(DataOutput).

A - 1 & 4

B - 2 & 3

C - 3 & 4

D - 2 & 4