Cloudera CCA-470 問題集

質問 1：
You have a cluster running with the Fair in 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.
Which of the following describes how the Fair Scheduler operates? (Choose 2)
A. When job B gets submitted, it will get assigned tasks, while job A continues to run with fewer tasks.
B. When job A gets submitted, it consumes all the task slots.
C. When job B gets submitted, job A has to finish first, before job B can get scheduled.
D. When job A gets submitted, it doesn't consume all the task slots.
正解：B,C
解説: (Topexam メンバーにのみ表示されます)

質問 2：
For a MapReduce job, on a cluster running MapReduce v1 (MRv1), what's the relationship between tasks and task templates?
A. There are always at least as many task attempts as there are tasks.
B. There are always at most as many tasks attempts as there are tasks.
C. The developer sets the number of task attempts on job submission.
D. There are always exactly as many task attempts as there are tasks.
正解：D

質問 3：
You are running a Hadoop cluster with NameNode on host mynamenode, a secondary NameNode on host mysecondary and DataNodes.
Which best describes how you determine when the last checkpoint happened?
A. Connect to the web UI of the NameNode (http://mynamenode:50070/) and look at the "Last Checkpoint" information
B. Execute hdfs dfsadmin -saveNameSpace on the command line which returns to you the last checkpoint value in fstime file.
C. Connect to the web UI of the Secondary NameNode (http://mysecondarynamenode:50090) and look at the "Last Checkpoint" information
D. Execute hdfs dfsadmin -report on the command line in and look at the Last Checkpoint information.
正解：C
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 three distcp features can you utilize on a Hadoop cluster?
A. Use distcp to copy HBase table files.
B. Use distcp to copy files only between two clusters or more. You cannot use distcp to copy data between directories inside the same cluster.
C. Use distcp to run an internal MapReduce job to copy files.
D. Use distcp to copy data between directories inside the same cluster.
E. Use distcp to copy physical blocks from the source to the target destination in your cluster.
正解：A,C,D
解説: (Topexam メンバーにのみ表示されます)

質問 6：
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)