When we talk about the average salary of a Big Data Hadoop developer, it is close to 135 thousand dollars per annum. In European countries as well as in the United Kingdom, with the big data Hadoop certification, one can simply earn more than £67,000 per annum. These data reflect the reality of how great the career is. It was no less than a decade when companies are generating more than ten terabytes of data, we're paying heavily two database managers, and we are not satisfied with their services. For companies like Google, after a surge and lateral expansion, managing data became very cumbersome. Scientists and engineers of Google pioneer a project that was further known to be Hadoop. The idea here was to play with different types of data like XML, text, binary, SQL, log, and objects but further mapping them and reducing them do a single structured architecture.

1. HADOOP
INTERVIEW
QUESTIONS AND
ANSWERS 2021

2. Basic Hadoop Interview
Questions and Answers
Q1. what do you mean by Hadoop and its component?
The ideal way to answer this question is by sticking to the main components
that are the storage units and processing framework. When it comes to
defining Hadoop, you have to start with big data. Below we have provided
you a sample answer to which you can relate to and form your own
answers.
It is an open-source distributed processing framework pet stores, and the
process is big data. The end users can use this software and have access to
a network of many computers to resolve the problems related to mammoth
amounts of data and its computation. It is commonly used for commodity
hardware and is design for computer clusters. The best part is all the
common occurrences of problems and failures in the hardware his
fundamentally handled by the framework itself.
.
To Learn More Visit Link in the
description

3. Q2. Define HDFS and
YARN?
Hadoop distributed file system is known as HDFS, file yet another
resource negotiator is known as YARN.
HDFS is designed to store data in blocks in a diverse environment
and architecture. The environment consists of a master node,
which is called a name node. This is where all the data are
structured in blocks, location, and replication factors—making it to
metadata information repository. The slave nodes which are
responsible for the storage and blocks communication and
replication factors are known as a data node. The name node is
responsible for managing all the data nodes in our master and slave
topology.
While yet another resource negotiator can we define as a
processing framework that provides execution and management of
resources stored in the environment, it has a resource manager
who is responsible for acting upon the received processing
request. It corresponds with node managers and initiates actual
processing. It works in a batch mode and allocates resources to
applications based on their needs. An old manager, which is a part
of YARN, can be found in every data node responsible for the
execution of the task.
To Learn More Visit Link
in the description

4. FsImage, otherwise called metadata replica, is used to start a
new name node in the file system.
Then we start the configuration process. Further data notes, as
well as the clients, are acknowledged as a new NameNode after
the initiation of the first step.
In the end, we get enough block reports from the data nodes
that are loaded from the last checkpoint FsImage.
H we have to follow a three-step approach in troubleshooting
Hadoop cluster up problems, and they are:
This usually takes up a lot of time to re-direct and extract the data,
which may serve as a great challenge while doing routine
maintenance. But with the use of high availability architecture, we
can eliminate it in no time
Example
Q3. Illustrate the steps to fix the name
node when it is a malfunction?

5. Q4. What do you mean by a
checkpoint?
User------fsimage-----checkpointing-----
mkdir”/foo” ----- NameNode-----edit log.
This is a process that takes the request of file system
metadata replica, edits log, and further compacts them
into a new FsImage.
1.Check preconditions----GET/ getimage?putimage=1--
----- HTTP Get to getimage------ GET/ getimage-----
new fsimage data----- saves to intermediate filename--
---putimage completes----- save MD5 file & renames
fsimage to final desitination.
1.

6. Q5. Illustrate how HDFS fault is
tolerant?
The problem with a single machine is that in a legacy system, the relational
database performs both read and write operations by the users. If any
contingency situation arises like a mechanical failure or power down from
the user has to wait still, the issue is corrected manually. Another set of
problems with legacy systems is that we have to store the data in a range
of gigabytes. The data storage capacity was limited and enhanced data
storage capacity. We have to buy a new server machine. It directly fixes the
cost of maintaining file systems and issues related to it. With the all-new
Hadoop distributed file system, we can overcome storage capacity
problems and tackle favorable conditions like machine failure, RAM crash,
and power down.
To Learn More Visit Link
in the description

7. Replication mechanism
RAID or Redundant Array of Independent
Disks makes practical usage of the Erasure
coding by having effective space-saving
methods. It can reduce up to 50% of storage
overhead for each strip of the original dataset.
Erasure Coding
The idea here is to create a replica of the data
block & store then in the DataNode. The
replicas list entirely depends upon the
replication factor that ensures no loss of data
due to replicas stored on a variety of
machines.

8. Q6. What are the common input
formats in Hadoop?
In Hadoop, we have provisions made
accessible for input formats in three
significant categories, and they are as
follows:
The input format for reading files in
sequence, also known as Sequence File
Input format.
To Learn More Visit Link
in the description

9. Pre-record to present
anytime, anywhere
In Hadoop, we have provisions made accessible for
input formats in three significant categories, and
they are as follows:
The input format for reading files in sequence, also
known as Sequence File Input format.
The default input format of the Hadoop is known as
the Text Input Format.
The format that helps users to read plain text files is
called Key-Value Input Format.
Q8. Define Active and
Passive NameNodes?
The NameNode that helps to run the
Hadoop cluster resource is called the
Active NameNode. While the standby
NameNode that helps in the storage of data
for the Active NameNode is otherwise
called as Passive NameNode. They both are
the components of the High Availability
Hadoop System, whose sole purpose is to
provide fluidity and increase the
effectiveness of the cluster and the system
files.
To Read Full Article Visit
Link in the description

10. LIKE IT IF YOU LOVE IT
Follow us and keep
updated
Mail Your Queries
Support @ Sprintzeal.com