Cloudera CCA-410 問題集

質問 1：
Identify four characteristics of a 300MB file that has been written to HDFS with block size of 128MB and all other Hadoop defaults unchanged?
A. The file will consume 1152MB of space in the cluster
B. Each block will be replicated three times
C. The third Initial block will be 44 MB
D. Each block will be replicated nine times
E. Two of the initial blocks will be 128MB
F. The third block will be 64MB
G. The file will be split into three blocks when initially written into the cluster
H. All three blocks will be 128MB
正解：B,C,E,G
解説: (Topexam メンバーにのみ表示されます)

質問 2：
You set up the Hadoop cluster using NameNode Federation. One NameNode manages the/users namespace and one NameNode manages the/data namespace. What happens when client tries to write a file to/reports/myreport.txt?
A. The file writes fails silently; no file is written, no error is reported.
B. The client throws an exception.
C. The file successfully writes to /users/reports/myreports/myreport.txt.
D. The file successfully writes to /report/myreport.txt. The metadata for the file is managed by the first NameNode to which the client connects.
正解：D
解説: (Topexam メンバーにのみ表示されます)

質問 3：
What happens if a Mapper on one node goes into an infinite loop while running a MapReduce job?
A. The Mapper will run indefinitely; the TaskTracker must be restarted to kill it
B. The job will immediately fail.
C. After a period of time, the TaskTracker will kill the Map Task.
D. After a period of time, the JobTracker will restart the TaskTracker on the node on which the map task is running
正解：C
解説: (Topexam メンバーにのみ表示されます)

質問 4：
Your Hadoop cluster contains nodes in three racks. Choose which scenario results if you leave the dfs.hosts property in the NameNode's configuration file empty (blank)?
A. Any machine running the DataNode daemon can immediately join the cluster.
B. Presented with a blank dfs.hosts property, the NameNode will permit DataNodes specified in mapred.hosts to join the cluster.
C. No new can be added to the cluster until you specify them in the dfs.hosts file.
D. The NameNode will update dfs.hosts property to include machines running the DataNode daemon on the next NameNode reboot or with a dfsadmin -refreshNodes.
正解：C
解説: (Topexam メンバーにのみ表示されます)

質問 5：
Under which scenario would it be most appropriate to consider using faster (e.g 10 Gigabit) Ethernet as the network fabric for your Hadoop cluster?
A. When the typical workloads generates a large amount of output data, significantly larger than the amount of intermediate data.
B. When the typical workloads consists of processor-intensive tasks.
C. When the typical workloads generates a large amount of intermediate data, on the order of the input data itself.
D. When the typical workloads consumes a large amount of input data, relative to the entire capacity of HDFS.
正解：C
解説: (Topexam メンバーにのみ表示されます)

質問 6：
You have a cluster running with the fair scheduler enabled and configured. You submit multiple jobs to the cluster. Each job is assigned to a pool. What are the two key points to remember about how jobs are scheduled with the fair scheduler?
A. Each pool gets 1/N of the total available tasks slots, where N is the no of jobs running on the cluster
B. Each pools share of task slots may change throughout the course of job execution
C. Pools are assigned priorites.pools with higher priorities an executed b4 pools with lower priorities
D. Each pool gets 1/M of the total available tasks slots, where M is the no. of nodes in the cluster
E. Each pools share of the tasks slots remains static within the execution of any individual job
F. Pools get a dynamically-allocated share of the available task slots (subject to additional constraints)
正解：B,F
解説: (Topexam メンバーにのみ表示されます)

質問 7：
When requesting a file, how does HDFS retrieves the blocks associated with that file?
A. the namenode requires the datanode for the block ID's
B. The namenode reads the block ID's from memory
C. the namenode reads the block ID's from disk
D. the client polls the datanodes for the block ID's
正解：C
解説: (Topexam メンバーにのみ表示されます)