Top 20 Hadoop Admin Interview Questions and Answers

Hadoop Admin Interview Questions

Hey, are you fresher or experienced and looking for Hadoop admin interview questions. If yes, then don't worry you are in the right place. Whatever you want is you'll definitely find here. I'm here sharing the top 20 interview questions with answers which will definitely help you to crack your interview easily. So, don't skip any part and stick to the post up to the end. Firstly let me explain to you some basic components of the Hadoop Administrator post i.e., What are the job responsibilities, skills, etc.

Whats are the job responsibilities of the Hadoop Administrator?

Hadoop Administrator is a person who administrates and manage Hadoop clusters. The main responsibility of the Hadoop admin is to install and monitor Hadoop clusters. A Hadoop administrator is one who responsible to keep the company's Hadoop cluster safe and error-free. Hadoop Administrator Key Responsibilities include... - Deploying and maintaining Hadoop clusters - Adding and removing nodes using tools - Keep safely running the entire Hadoop structure - Daily backups - Other recovery tasks

Skills required to become Hadoop Administrator

There are several skills required for a Hadoop admin, this job is kind of challenging job. But if you want to become a Hadoop admin then, you need to have a capacity to solve tough queries and accept new challenges daily. You need to be updated with new upcoming technologies and techniques. Hadoop Administrator Key Skills include... - Deep knowledge of UNIX/LINUX operating systems. - Deep knowledge of cluster monitoring tools. ex., Ambari, Ganglia, etc. - Basic knowledge of Networking. - Deep understanding of the Hadoop Ecosystem. ex., Apache Hive, Pig, Mahout, etc.
Now let's come back to Hadoop admin interview questions, here below I've listed 20 questions with answers that help you to crack the Hadoop admin interview easily.

Hadoop Admin Interview Questions and Answers

What is Big Data? Answer: Big Data is a term that describes a large scale of a data set that is very hard to store, capture, process, retrieve, and analyze with the help of database management tools. What are the characteristics of Big Data? Answer: Volume: Every organization collect data from many sources like Social media, E-commerce websites, Share market, etc. Velocity: The speed at which the data is generating is very huge and wide. Variety: The type and nature of the data like audio, video, images, etc. These are the characteristics of Big data.
What are the challenges we face in handling Big Data? Answer: There are many challenges we face in current days, few of them are... Data Storage: Physical storage, space requirements, and also power cost. Difficulties: Capture, search, sharing, analytics, etc Data Processing: Content management and information.

What is Hadoop? Answer: When Big data emerged as a problem, Hadoop evolved as a solution to it. Apache Hadoop is a framework that provides various services, tools to store and process Big Data. There are many big companies are using Hadoop in current days.
What is the difference between RDBMS and Hadoop? Answer: RDBMS stands for "Relational Database Management System" it is a traditional row-column database used for traditional systems to do many tasks like making a report, archive data, etc. Whereas Hadoop has the capability to store huge amounts of data in distributed file systems. Basically, Hadoop can able to handle bigger data than RDBMS. RDBMS works on the structure data and Hadoop works on unstructured data.
Tell me in what format Hadoop handles data? Answer: Hadoop handles data in the format of Key or Value.
What is HDFS? Answer: HDFS stands for "Hadoop Distributed File System", it is a storage unit of Hadoop. The main function of HDFS is, it is responsible for storing different kinds of data in a distributed environment. Basically, it follows master and slave architecture.
Why we stored files in a redundant manner in HDFS? Answer: We stored files in a redundant manner in HDFS because to ensure durability against failures.
What is Namenode? Answer: Namemode is the master of the entire Hadoop system. It is a high availability of the machine and a single point of failure in HDFS. Namenode has metadata for the HDFS.
What is Datanode? Answer: Datanode is the place where data actually stored in the system. Basically, the data sent by Namenode is store in the Datanode.
What happens when Datanode fails? Answer: When Datanode fails... 1. When Datanode failed all the tasks are re-scheduled. 2. Namenode detects the failure of the Datanode. 3. Then the job tracker assigns that task to another Datanode.
What is MapReduce? Answer: MapReduce is the main component in the entire Hadoop structure. It's the programming paradigm that process and handles large data sets across hundreds and thousands of server in the Hadoop cluster. Basically, it is a framework that we can use to write applications to process huge amounts of data.

Tell me how many daemon processes run on a Hadoop cluster? Answer: Basically there are a total of 5 daemon processes run on a Hadoop cluster... Namenode, JobTracker, and Secondary Namenode run on a master node. And Datanode and TaskTracker run on a slave node.
What is Job tracker? Answer: It is a daemon that runs on a Namenode in the Hadoop cluster. The job tracker assigns the tasks to the different task tracker. It is a single point of failure. If the Job tracker down due to some reason then all the running jobs will be down. The job tracker receives a heartbeat from the task tracker based on Job tracker whether the assigned task is completed or not.
What is Task tracker? Answer: Task tracker is also a daemon process in the Hadoop cluster. Task tracker manages and handles the execution of individual tasks on the slave node. The main working of Task tracker is when a client submits a job, the job tracker will initialize that job and split amongst different task trackers to perform MapReduce tasks. While performing this task, the task tracker simultaneously communicating with the job tracker by sending heartbeats. If the job tracker doesn't receive a heartbeat from the task tracker in a specific time period, then it will assume that the task tracker has crashed. And then it will assign that task to another task tracker in the cluster.
Tell me the names of some companies that use Hadoop? Answer: There are many companies that use Hadoop, few of them are... Yahoo, Facebook, Cloudera, Amazon, Twitter, eBay, IBM, etc.
What are the main components of the Hadoop application? Answer: Core components of the Hadoop application are... Hadoop Common, HDFS, Hadoop MapReduce and YARN.
What is the port number for Namenode, Job Tracker and Task tracker? Answer: 1. Namenode=50070 2. Job Tracker=50030 3. Task Tracker=50060
What happens when a user submits a Hadoop job when Namenode is down? Answer: The Hadoop job fails if the Namenode is down.
Which OS and JAVA version is required to run Hadoop? Answer: Basically Linux and Windows are the supported operating systems for Hadoop. And if I talk about JAVA then, 1.6x or higher version is good to run Hadoop.
Can Hadoop handle streaming data? Answer: Yes, there are several technologies are available in Hadoop like Apache Kafka, Apache Spark, and Apache Flume which can handle streaming data. So, that's all for today! If you like the article then share it with your friends who really need these questions. And best luck from me for your interview with Hadoop Admin. Thank you!

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