501-01 Hadoop Practice Questions

You want to understand more about how users browse your public website. For example, you want to know which pages they visit prior to placing an order. You have a server farm of 200 web servers hosting your website. Which is the most efficient process to gather these web server across logs into your Hadoop cluster analysis?

• AA. Sample the web server logs web servers and copy them into HDFS using curl
• BB. Ingest the server web logs into HDFS using Flume
• CC. Channel these clickstreams into Hadoop using Hadoop Streaming
• DD. Import all user clicks from your OLTP databases into Hadoop using Sqoop

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?

• AA. The user is not authorized to run the job on the cluster
• BB. The output directory already exists
• CC. The name of the driver has been spelled incorrectly on the command line
• DD. The directory name is misspelled in HDFS

For each YARN job, the Hadoop framework generates task log file. Where are Hadoop task log files stored?

• AA. Cached by the NodeManager managing the job containers, then written to a log directory on the NameNode
• BB. Cached in the YARN container running the task, then copied into HDFS on job completion
• CC. In HDFS, in the directory of the user who generates the job
• DD. On the local disk of the slave mode running the task

You are running Hadoop cluster with all monitoring facilities properly configured. Which scenario will go undeselected?

• AA. HDFS is almost full
• BB. The NameNode goes down
• CC. A DataNode is disconnected from the cluster
• DD. Map or reduce tasks that are stuck in an infinite loop