For each YARN job, the Hadoop framework generates task log file. Where are Hadoop task log files stored?
A. Cached by the NodeManager managing the job containers, then written to a log directory on the NameNode
B. Cached in the YARN container running the task, then copied into HDFS on job completion
C. In HDFS, in the directory of the user who generates the job
D. On the local disk of the slave mode running the task
You want to node to only swap Hadoop daemon data from RAM to disk when absolutely necessary. What should you do?
A. Delete the /dev/vmswap file on the node
B. Delete the /etc/swap file on the node
C. Set the ram.swap parameter to 0 in core-site.xml
D. Set vm.swapfile file on the node
E. Delete the /swapfile file on the node
Which YARN process run as "container 0" of a submitted job and is responsible for resource qrequests?
A. ApplicationManager
B. JobTracker
C. ApplicationMaster
D. JobHistoryServer
E. ResoureManager
F. NodeManager
You suspect that your NameNode is incorrectly configured, and is swapping memory to disk. Which Linux commands help you to identify whether swapping is occurring? (Select all that apply)
A. free
B. df
C. memcat
D. top
E. jps
F. vmstat
G. swapinfo
You are planning a Hadoop cluster and considering implementing 10 Gigabit Ethernet as the network fabric. Which workloads benefit the most from faster network fabric?
A. When your workload generates a large amount of output data, significantly larger than the amount of intermediate data
B. When your workload consumes a large amount of input data, relative to the entire capacity if HDFS
C. When your workload consists of processor-intensive tasks
D. When your workload generates a large amount of intermediate data, on the order of the input data itself
What two processes must you do if you are running a Hadoop cluster with a single NameNode and six DataNodes, and you want to change a configuration parameter so that it affects all six DataNodes. (Choose two)
A. You must modify the configuration files on the NameNode only. DataNodes read their configuration from the master nodes
B. You must modify the configuration files on each of the DataNodes machines
C. You don't need to restart any daemon, as they will pick up changes automatically
D. You must restart the NameNode daemon to apply the changes to the cluster
E. You must restart all six DatNode daemon to apply the changes to the cluster
Given:
You want to clean up this list by removing jobs where the State is KILLED. What command you enter?
A. Yarn application refreshJobHistory
B. Yarn application kill application_1374638600275_0109
C. Yarn rmadmin refreshQueue
D. Yarn rmadmin kill application_1374638600275_0109
You are configuring a server running HDFS, MapReduce version 2 (MRv2) on YARN running Linux. How must you format underlying file system of each DataNode?
A. They must be formatted as HDFS
B. They must be formatted as either ext3 or ext4
C. They may be formatted in any Linux file system
D. They must not be formatted - - HDFS will format the file system automatically
You have recently converted your Hadoop cluster from a MapReduce 1 (MRv1) architecture to MapReduce 2 (MRv2) on YARN architecture. Your developers are accustomed to specifying map and reduce tasks (resource allocation) tasks when they run jobs: A developer wants to know how specify to reduce tasks when a specific job runs. Which method should you tell that developers to implement?
A. MapReduce version 2 (MRv2) on YARN abstracts resource allocation away from the idea of "tasks" into memory and virtual cores, thus eliminating the need for a developer to specify the number of reduce tasks, and indeed preventing the developer from specifying the number of reduce tasks.
B. In YARN, resource allocations is a function of megabytes of memory in multiples of 1024mb. Thus, they should specify the amount of memory resource they need by executing D mapreducereduces.memory-mb-2048
C. In YARN, the ApplicationMaster is responsible for requesting the resource required for a specific launch. Thus, executing D yarn.applicationmaster.reduce.tasks=2 will specify that the ApplicationMaster launch two task contains on the worker nodes.
D. Developers specify reduce tasks in the exact same way for both MapReduce version 1 (MRv1) and MapReduce version 2 (MRv2) on YARN. Thus, executing D mapreduce.job.reduces-2 will specify reduce tasks.
E. In YARN, resource allocation is function of virtual cores specified by the ApplicationManager making requests to the NodeManager where a reduce task is handeled by a single container (and thus a single virtual core). Thus, the developer needs to specify the number of virtual cores to the NodeManager by executing p yarn.nodemanager.cpu-vcores=2
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. yarn.application.child.java.opts=-Xsx3072m
B. yarn.application.child.java.opts=-Xmx3072m
C. mapreduce.map.java.opts=-Xms3072m
D. mapreduce.map.java.opts=-Xmx3072m
