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Cloudera Certified Developer for Apache Hadoop Sample Questions:
1. Which two of the following are valid statements? (Choose two)
A) HDFS is a distributed file system that runs on top of native OS filesystems and is well suited to storage of very large data sets.
B) HDFS has the Characteristic of supporting a "write once, read many" data access model.
C) HDFS is optimized for storing a large number of files smaller than the HDFS block size.
D) HDFS is a distributed file system that replaces ext3 or ext4 on Linux nodes in a Hadoop cluster.
2. You have the following key value pairs as output from your Map task:
(The, 1)
(Fox, 1)
(Runs, 1)
(Faster, 1)
(Than, 1)
(The, 1)
(Dog, 1)
How many keys will be passed to the reducer?
A) Four
B) One
C) Six
D) Five
E) Two
F) Three
3. Which statement best describes the data path of intermediate key-value pairs (i.e., output of the mappers)?
A) Intermediate key-value pairs are written to the local disks of the machines running the map tasks, and then copied to the machine running the reduce tasks.
B) Intermediate key-value pairs are written to HDFS. Reducers read the intermediate data from HDFS.
C) Intermediate key-value pairs are written to the local disks of the machines running the map tasks, and are then copied to HDFS. Reducers read the intermediate data from HDFS.
D) Intermediate key-value pairs are written to HDFS. Reducers copy the intermediate data to the local disks of the machines running the reduce tasks.
4. Which happens if the NameNode crashes?
A) HDFS becomes unavailable until the NameNode is restored.
B) The Secondary NameNode seamlessly takes over and there is no service interruption.
C) HDFS becomes temporarily unavailable until an administrator starts redirecting client requests to the Secondary NameNode.
D) HDFS becomes unavailable to new MapReduce jobs, but running jobs will continue until completion.
5. You have written a Mapper which invokes the following five calls to the outputcollector.collect method:
How many times will the Reducer's reduce method be invoked.
A) 5
B) 1
C) 0
D) 3
E) 6
Solutions:
| Question # 1 Answer: A,B | Question # 2 Answer: C | Question # 3 Answer: A | Question # 4 Answer: A | Question # 5 Answer: D |
By Yvette
