Cloudera CCA-410 問題集

質問 1：
You set the value of dfs.block.size to 64MB in hdfs-site.xml on a client machine, but you set the same property to 128MB on your clusters name node. What happens when the client writes a file to HDFS?
A. A block size of 128MB will be used
B. A block size of 64MB will be used
C. The file will be written successfully with a block size of 64MB but client attempting to read the file will fail because the namenode believes the blocks to be 128MB in size
D. An execution will be thrown when the client attempts to write the file, because the values are different.
正解：B
解説: (Topexam メンバーにのみ表示されます)

質問 2：
What are the permissions of a file in HDFS with the following:rw-rw-r-x?
A. the owner and group cannot delete the file, but other can
B. HDFS runs in user space which makes all users with access to the namespace able to read, write and modify all files
C. the owner and group can read the file other can't
D. the owner and group can modify the contents of the file other can't
E. No one can modify the content of the file
正解：D
解説: (Topexam メンバーにのみ表示されます)

質問 3：
Which three processes does HDFS High Availability (HA) enable on your cluster?
A. Write data to two clusters simultaneously
B. Shut one NameNode down for maintenance without halting the cluster
C. Manually 'fail over' between NameNodes
D. Configure unlimited hot standby NameNode.
E. Automatically 'fail over' between NameNodes if one goes down
正解：B,C,E
解説: (Topexam メンバーにのみ表示されます)

質問 4：
In a cluster configured with HDFS High Availability (HA) but NOT HDFS federation, each map task run:
A. In the same Java Virtual Machine as the JobTracker.
B. In its own Java Virtual Machine.
C. In the same Java Virtual Machine as the TaskTracker
D. In the same Java Virtual Machine as the DataNode.
正解：B
解説: (Topexam メンバーにのみ表示されます)

質問 5：
Which two daemons must be installed on master nodes in hadoop cluster running mapreduce V1 (MRV1)?
A. Tasktracker
B. Resourcemanager
C. ApplicationMaster
D. Datanode
E. Hmaster
F. Zookeeper
G. Namenode
正解：C,G
解説: (Topexam メンバーにのみ表示されます)

質問 6：
On a cluster running MapReduce v1 (MRv1), a MapReduce job is given a directory of 10 plain text as its input directory. Each file is made up of 3 HDFS blocks. How many Mappers will run?
A. 10
B. We cannot say; the number of Mappers is determined by the developer
C. 30
D. 1
正解：C

質問 7：
What action occurs automatically on a cluster when a DataNode is marked as dead?
A. The replication factor of the files which had blocks stored on the dead DataNode is temporarily reduced, until the dead DataNode is recovered and returned to the cluster.
B. The NameNode forces re-replication of all the blocks which were stored on the dead DataNode.
C. The next time a client submits job that requires blocks from the dead DataNode, the JobTracker receives no heart beats from the DataNode. The JobTracker tells the NameNode that the DataNode is dead, which triggers block re-replication on the cluster.
D. The NameNode informs the client which write the blocks that are no longer available; the client then re-writes the blocks to a different DataNode.
正解：B
解説: (Topexam メンバーにのみ表示されます)