Cloudera CCA-500 問題集

質問 1：
You are running a Hadoop cluster with MapReduce version 2 (MRv2) on YARN. You consistently see that MapReduce
map tasks on your cluster are running slowly because of excessive garbage collection of JVM, how do you increase
JVM heap size property to 3GB to optimize performance?
A. mapreduce.map.java.opts=-Xms3072m
B. mapreduce.map.java.opts=-Xmx3072m
C. yarn.application.child.java.opts=-Xmx3072m
D. yarn.application.child.java.opts=-Xsx3072m
正解：A
解説: (Topexam メンバーにのみ表示されます)

質問 2：
Which process instantiates user code, and executes map and reduce tasks on a cluster running MapReduce v2 (MRv2)
on YARN?
A. TaskTracker
B. NameNode
C. ResourceManager
D. ApplicationMaster
E. NodeManager
F. DataNode
G. JobTracker
正解：G

質問 3：
You decide to create a cluster which runs HDFS in High Availability mode with automatic failover, using Quorum
Storage. What is the purpose of ZooKeeper in such a configuration?
A. It monitors an NFS mount point and reports if the mount point disappears
B. It only keeps track of which NameNode is Active at any given time
C. It both keeps track of which NameNode is Active at any given time, and manages the Edits file. Which is a log of
changes to the HDFS filesystem
D. If only manages the Edits file, which is log of changes to the HDFS filesystem
E. Clients connect to ZooKeeper to determine which NameNode is Active
正解：B
解説: (Topexam メンバーにのみ表示されます)

質問 4：
Each node in your Hadoop cluster, running YARN, has 64GB memory and 24 cores.
Your yarn.site.xml has the following configuration:
<property>
<name>yarn.nodemanager.resource.memory-mb</name>
<value>32768</value>
</property>
<property>
<name>yarn.nodemanager.resource.cpu-vcores</name>
<value>12</value>
</property>
You want YARN to launch no more than 16 containers per node. What should you do?
A. Modify yarn-site.xml with the following property:
<name>yarn.nodemanager.resource.cpu-vccores</name>
B. Modify yarn-site.xml with the following property:
<name>yarn.scheduler.minimum-allocation-mb</name>
<value>2048</value>
C. No action is needed: YARN's dynamic resource allocation automatically optimizes the node memory and cores
D. Modify yarn-sites.xml with the following property:
<name>yarn.scheduler.minimum-allocation-mb</name>
<value>4096</value>
正解：A

質問 5：
Which YARN daemon or service monitors a Controller's per-application resource using (e.g., memory CPU)?
A. ResourceManager
B. ApplicationManagerService
C. ApplicationMaster
D. NodeManager
正解：C

質問 6：
A user comes to you, complaining that when she attempts to submit a Hadoop job, it fails. There is a Directory in HDFS
named /data/input. The Jar is named j.jar, and the driver class is named DriverClass.
She runs the command:
Hadoop jar j.jar DriverClass /data/input/data/output
The error message returned includes the line:
PriviligedActionException as:training (auth:SIMPLE)
cause:org.apache.hadoop.mapreduce.lib.input.invalidInputException:
Input path does not exist: file:/data/input
What is the cause of the error?
A. The directory name is misspelled in HDFS
B. The Hadoop configuration files on the client do not point to the cluster
C. The output directory already exists
D. The user is not authorized to run the job on the cluster
E. The name of the driver has been spelled incorrectly on the command line
正解：D