Author: Piyush Rana

Reactive Architecture

Reading Time: 2 minutes Recently I got an invitation to present a guest lecture for faculty of Engineering colleges in ABES college of Engineering. I came up with the most trending topic i.e Reactive Architecture. We talked about what is this buzzing keywords and why does it came into existence. Also What are the challenges one were facing and how are the real world problems being solved by using Continue Reading

Did you manage your garbage efficiently?

Reading Time: 3 minutes In the JVM world if you talked about Java Memory Management then first you want to understand the working of Java Garbage Collection. While working on JVM based application it becomes super easy when JVM itself manages your GC for you but the problem starts when you start facing performance degradation and that too because of in-efficient GC. So let’s start with understanding what is JVM GC model and Continue Reading

Akka Stream: Map And MapAsync

Reading Time: 2 minutes In this blog, we will discuss what are “map” and “mapAsync” when used in the Akka stream and how to use them. The difference is highlighted in their signatures:- Flow.map takes in a function that returns a type T, while Flow.mapAsync takes in a function that returns a type Future[T]. Let’s take one practical example to understand both:- Problem – Suppose we have a user with a userId and Continue Reading

Generate Docker Image For Mesosphere Kafka Client

Reading Time: 2 minutes Have you ever tried to access Kafka running on mesos on top of DCOS, and figure out that you end up with no latest Kafka client image in the docker hub? I have uploaded a new image with the Latest Kafka Stable Version 2.0.0, and one can get it easily – docker pull piyushdocker/kafka-client-2.0.0-image If you want to create your own image with any other Continue Reading

Transport Cinnamon Matrices From Lagom To Prometheus

Reading Time: 3 minutes Monitoring is a pain when it comes to distributed applications, and even more when you have shared or non-shared variables to monitor in your application. Here in this blog, I’ll explain two tools which can ease the monitoring efforts, one for generating metrics called Cinnamon and other to visualize them, called Prometheus. Let’s have a quick brief intro about these two – Prometheus – An open-source monitoring system with Continue Reading

ScalaTest – How to Disable Test Cases using Tagging

Reading Time: 3 minutes Scala Test – How to disable Test Cases using Tagging Tagging your tests ScalaTest allows you to define some test categories, to “tag” tests as belonging to those categories, and filter tests to run based on their tags. For example, you could tag some tests as being slow and chose to exclude the slow tests during some runs, or say you have some intergration test Continue Reading

Akka Split Brain Resolver

Reading Time: 1 minute Hello all, Knoldus organized a knolx session on the topic “Akka Split Brain Resolver” on Friday, 1st September 2017 In this session we have discussed about When operating an Akka cluster you must consider how to handle network partitions (a.k.a. Split Brain Scenarios) and machine crashes (including JVM and hardware failures). This is crucial for correct behavior if you use Cluster Singleton or Cluster Sharding, Continue Reading

Automatic Deployment Of Lagom Service On ConductR On DCOS

Reading Time: 2 minutes In our previous blog we have seen how to deploy the lagom service on conductr – https://blog.knoldus.com/2017/05/25/deploying-the-lagom-service-on-conductr/ In this blog we will create script to deploy your Lagom service on conduct present or running on top of DCOS. There are two types of automatic deployments can be done – Deploying from scratch (stop the current Lagom bundle and deploy the new one) Rolling/Incremental Deployment( Overriding Continue Reading

Akka Split Brain Resolver – Problem and its Solution

Reading Time: 6 minutes AKKA Split Brain Resolver When operating an Akka cluster the developer will surely comes around network partitions (Split Brain scenarios) and machine crashes. There are multiple strategies present by lightbend to handle such erratic behavior and, after a deeper explanation of the problem we are facing, I will try to present them along with their pros and cons using the Split Brain Resolver in Akka, Continue Reading

Deploying The Lagom Service On ConductR

Reading Time: 3 minutes In the previous blog, we have discussed how to create a Lagom service based architecture with a beautiful word count example. One can refer to the below link- https://blog.knoldus.com/2017/03/27/lagom-framework-the-legacy-wordcount-example/ In this blog we will discuss now how we can deploy the Lagom service on conductR. What is ConductR? As described by lightbend – “” ConductR is a “batteries included” approach to managing distributed systems. No Continue Reading

Lagom Framework: The Legacy WordCount Example

Reading Time: 3 minutes What is Lagom? Lagom is an open source micro-service framework, built with Akka message-driven runtime and Play web framework and finally light bend service orchestration. Mixing all these technologies abstracts away the complexities of building, running, and managing microservice architectures. Lagom is a Swedish word meaning “just the right amount”. Often, when people talk about microservices, they focus on the micro part of the name, Continue Reading

Spark Cassandra Connector On Spark-Shell

Reading Time: 2 minutes Using Spark-Cassandra-Connector on Spark Shell Hi All , In this blog we will see how we can execute our spark code on spark shell using Cassandra . This is very efficient at testing or learning time , where we have to execute our code on spark shell rather than doing on any IDE . Here we will use spark version –  1.6.2  you can download Continue Reading

Transaction Management in Cassandra

Reading Time: 4 minutes As we are all from the Sql Background and its been ages SQL rules the market , so transaction are something favorite to us . While Cassandra does not support ACID (transaction) properties but it gives you the ‘AID’ among it . That is Writes to Cassandra are atomic, isolated, and durable in nature. The “C” of ACID—consistency—does not apply to Cassandra, as there is Continue Reading

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