How does YARN interact with Zookeeper to support High Availability?

In the Hadoop ecosystem, YARN, short for Yet Another Resource negotiator, holds the responsibility of resource allocation and job scheduling/management. The Resource Manager(RM), one of the components of YARN, is primarily responsible for accomplishing these tasks of coordinating with the various nodes and interacting with the client.

To learn more about YARN, feel free to visit here.

Architecture of YARN

Hence, Resource Manager in YARN is a single point of failure – meaning, if the Resource Manager is down for some reason, the whole of the system gets disturbed due to interruption in the resource allocation or job management, and thus we cannot run any jobs on the cluster. 

To avoid this issue, we need to enable the High Availability(HA) feature in YARN. When HA is enabled, we run another Resource Manager parallelly on another node, and this is known as Standby Resource Manager. The idea is that, when the Active Resource Manager is down, the Standby Resource Manager becomes active, and ensures smooth operations on the cluster. And the process continues.

Continue reading “How does YARN interact with Zookeeper to support High Availability?”

How to design a large-scale system to process emails using multiple machines [Zookeeper Use Case Study]?


As part of this blog we are going to discuss various ways of large scale system design and the pros-cons of each.

To get a fair understanding of this post, you should know what is distributed computing, what is deadlock and race conditions, locking in distributed systems and Zookeeper etc. Let’s get started.


Consider a situation where we have an email inbox that consists of emails, and emails are to be processed. For example, processing those emails and classifying each of the emails as spam or non-spam. The other example of the processing could be we are indexing the email so that the search could be performed.

We have an email-processor program, running on various machines distributed physically from each other.

Email processor program running on distributed systems

Now these machines need to somehow coordinate such that:

  • No email is processed two times
  • No email is left unprocessed
Continue reading “How to design a large-scale system to process emails using multiple machines [Zookeeper Use Case Study]?”

Introduction to Apache Zookeeper

In the Hadoop ecosystem, Apache Zookeeper plays an important role in coordination amongst distributed resources. Apart from being an important component of Hadoop, it is also a very good concept to learn for a system design interview.

If you would prefer the videos with hands-on, feel free to jump in here.

Alright, so let’s get started.


In this post, we will understand the following:

  • What is Apache Zookeeper?
  • How Zookeeper achieves coordination?
  • Zookeeper Architecture
  • Zookeeper Data Model
  • Some Hands-on with Zookeeper
  • Election & Majority in Zookeeper
  • Zookeeper Sessions
  • Application of Zookeeper
  • What kind of guarantees does ZooKeeper provide?
  • Operations provided by Zookeeper
  • Zookeeper APIs
  • Zookeeper Watches
  • ACL in Zookeeper
  • Zookeeper Usecases
Continue reading “Introduction to Apache Zookeeper”

Distributed Computing with Locks


Having known of the prevalence of BigData in real-world scenarios, it’s time for us to understand how they work. This is a very important topic in understanding the principles behind system design and coordination among machines in big data. So let’s dive in.


Consider a scenario where there is a resource of data, and there is a worker machine that has to accomplish some task using that resource. For example, this worker is to process the data by accessing that resource. Remember that the data source is having huge data; that is, the data to be processed for the task is very huge.

Continue reading “Distributed Computing with Locks”

Understanding Big Data Stack – Apache Hadoop and Spark


There are many Big Data Solution stacks.

The first and most powerful stack is Apache Hadoop and Spark together. While Hadoop provides storage for structured and unstructured data, Spark provides the computational capability on top of Hadoop.

Continue reading “Understanding Big Data Stack – Apache Hadoop and Spark”

Introduction to Big Data and Distributed Systems


As everyone knows, Big Data is a term of fascination in the present-day era of computing. It is in high demand in today’s IT industry and is believed to revolutionize technical solutions like never before.

Continue reading “Introduction to Big Data and Distributed Systems”

Big Data vs Machine Learning

Every day the world is advancing into the new level of industrialization and this has resulted in the production of a vast amount of data. And, at initial stages, people started considering it as a bane, but later they found out that it’s a boon. So, they started using this data in a productive way. Big data and machine learning are terminologies based on the concept of analyzing and using the same data. Let’s get into more details.

Continue reading “Big Data vs Machine Learning”

Use-cases of Machine Learning in E-Commerce

What computing did to the usual industry earlier, Machine Learning is doing the same to usual rule-based computing now. It is eating the market of the same. Earlier, in organizations, there used to be separate groups for Image Processing, Audio Processing, Analytics and Predictions. Now, these groups are merged because machine learning is basically overlapping with every domain of computing. Let us discuss how machine learning is impacting e-commerce in particular.

The first use case of Machine Learning that became really popular was Amazon Recommendations. Afterwards, the Netflix launched a challenge of Movie Recommendations which gave birth to Kaggle, now an online platform of various machine learning challenges.

Before I dive deep into the details further, lets quickly brief the terms that are found often confusing. AI stands for Artificial Intelligence which means being able to display human-like intelligence. AI is basically an objective. Machine learning is making computers learn based on historical or empirical data instead of explicitly writing the rules. Artificial Neural networks are the computing constructs designed on a similar structure like the animal brain. Deep Learning is a branch of machine learning where we use a complex Artificial Neural network for predictions.

Continue reading “Use-cases of Machine Learning in E-Commerce”

What are the pre-requisites to learn big data?

Pre-requisites for Big Data Hadoop

We, at CloudxLab, keep getting a lot of questions online, sometimes offline, asking us

“I want to learn big data. But, just don’t know whether I am eligible or not.”

“I am so and so, can I learn big data?”

We have compiled the most common questions here. And, we will answer each one of them.

So, here we go.

What are those questions?

  1. I am from a non-technical background. Can I learn big data?
  2. Do I need to know programming languages such as Java, Python, PHP, etc.?
  3. Or, since it is big data, do I need to know any other relational databases such as Oracle or in general do I need to be well versed with SQL?
  4. And also, do I need to know the Unix or Linux?

Continue reading “What are the pre-requisites to learn big data?”