Very large sets of data can be analyzed and used to extract information systematically from with the help of Big Data. This particular feature that Big Data offers makes it stand apart from traditional data-processing application software. Hadoop is a collection of software utilities that uses a network of multiple computer systems to solve problems related to massive amounts of data and computation. Hadoop provides a platform to process Big Data using the MapReduce programming model. Industries such as marketing, finance, and HR use Hadoop for Big Data. 80% of multinational companies use Hadoop for Big data and are regularly in search of professionals who have the skills and in-depth knowledge related to Big Data in Hadoop.
Here are top 10 interview questions with their answers that will help you get a job in 2020:
Question: What are the primary components of Hadoop?
Answer: The primary components of Hadoop are HDFS, Hadoop MapReduce, Hadoop Common, YARN, PIG & HIVE, HBase, Ambari, Oozie, ZooKeeper, Thrift, Avro, Apache Flume, Sqoop, Chukwa, Apache Mahout and Drill.
Question: What are the core concepts of the Hadoop framework?
Answer: There are two core concepts of Hadoop. They are:
Question: What are the most common input formats in Hadoop?
Answer: The three common input formats in Hadoop, namely Text Input Format, Sequence File Input Format and Key-Value Input Format. Text Input Format is the default input format in Hadoop. Sequence File Input Format helps in reading files in sequence. Key-Value Input Format is used to read plain text files.
Question: What is YARN?
Answer: YARN stands for Yet Another Resource Negotiator. It is the data processing framework that helps manage data resources and create an environment for successful processing.
Question: What do you mean by Rack Awareness?
Answer: The algorithm used by NameNode to determine the pattern in which data is blocked and their replicas are stored inside Hadoop cluster. This can be done with the help of rack definitions that reduce the congestion between data nodes.
Question: What are Active and Passive NameNodes?
Answer: Active and Passive NameNodes are two NameNodes contained in Hadoop system. Active NameNode runs the Hadoop cluster and Passive NameNode stores the data of Active NameNode. Passive NameNode can take the lead in case Active NameNode crashes. This helps the NameNode to always run in a cluster thus preventing the system from failing.
Question: Name some different schedulers in the Hadoop framework?
Answer: There are three different schedulers in Hadoop Framework. COSHH is used to reviewing the cluster and workload combined with heterogeneity to schedule decisions. FIFO Scheduler is used to line up jobs in a queue according to their time of arrival, without the need of using heterogeneity. Fair Sharing creates various individual users containing multiple maps. It also helps reduce slots that are used to execute specific jobs.
Question: What is Speculative Execution?
Answer: Some nodes run slower in Hadoop framework which can create constraints in the entire program. To prevent this, Hadoop launches an equivalent backup for that task and detects a task running slower than usual. While in the process, the master nodes execute both tasks simultaneously. The task which cannot be completed earlier is killed. This feature is called Speculation Execution in Hadoop.
Question: How to debug a Hadoop code?
Answer: To debug a Hadoop code, first the list of MapReduce tasks that are running is checked. After that, the presence of running orphaned tasks is checked. The location of Resource Manager logs can be found by Running “ps –ef l grep –I ResourceManager” and find an error related to a specific job id in the displayed result. After that, the worker node used to execute the task is identified. Then log in to the node and run “ps –ef I grep –iNodeManager.” Finally scrutinize the Node Manager Log.
Question: Name some practical applications of Hadoop.
Answer: Hadoop can be used for street traffic management, fraud detection, and prevention, analysis of customer data in real-time to improve customer service and accessing unstructured medical data from physicians, HCPs, etc.
The knowledge of answering the interview question of Big Data in Hadoop can only be obtained after having skills related to the software. You can learn Big Data in Hadoop anytime and anywhere with the help of Hadoop Administration Certification Training online training course offered by Multisoft Virtual Academy. To read more about the course and to join it, click here. You may visit our website www.multisoftvirtualacademy.com to have a look at 600+ online courses we offer to professionals and corporate companies.
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|26 Nov 2022||18 Dec 2022||24||06:00 PM - 09:00 PM||Sat, Sun|
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