What is Apache Kafka

I'd like to tell you what Apache Kafka is, but first, I wanna start with some background. For a long time now, we have written programs that store information in databases. Now, what databases encourage us to do is to think of the world in terms of things, things like, I don't know, users and maybe a thermostat. That's a thermometer, but you get the idea. Maybe a physical thing, like a train, let's see, here's a train. Things, there are things in the world. Database encourages us to think in those terms and those things have some state. We take that state, we store it in the database. This has worked well for decades, but now some people are finding that it's better, rather than thinking of things first, to think of events first. Now events have some state too, right? An event has a description of what happened with it, but the primary idea is that the event is an indication in time that the thing took place.

System Design Interview Distributed Cache

Today we design a distributed cache. We will start with some simple ideas and little by little evolve our design into a fully-fledged architecture. Approach, that we highly encourage you to use during a real interview. We also will discuss several important tips along the way. As usual, let's start with the problem statement. Let’s take a look at a typical setup, a web application backed by a data store. This data store may be a database or another web service. Client makes a call to the web application, which in turn makes a call to the data store and result is returned back to the client. There may be several issues with this setup. First, calls to the data store may take a long time to execute or may utilize a lot of system resources

System Design Interview Notification Service

Welcome to the system design interview channel. Today we design a notification service. Let's start with the problem statement. In the world of web services there are many scenarios when messages need to be sent in a reaction to some event. For example, when credit card transaction amount exceeded a limit and card holder needs to be notified. Or service monitoring system encountered a large number of faults produced by API and on-call engineer needs to be notified. In more general terms, let's say there is a component called Publisher which produces messages that need to be delivered to a group of other components, called Subscribers. We could have setup a synchronous communication between Publisher and Subscribers, when Publisher calls each Subscriber in some order and waits for the response. But this introduces many different challenges: hard to scale such system when number of subscribers and messages grow and hard to extend such solution to support different types of subscribers.

System Design Interview Distributed Message Queue

Today we design a distributed message queue. First, let’s make sure we are on the same page regarding the problem statement. What is a distributed message queue? Let's say there are two web-services called producer and consumer, and they need to communicate with each other. One option is to setup a synchronous communication, when producer makes a call to a consumer and waits for a response. This approach has its own pros and cons. Synchronous communication is easier and faster to implement. At the same time synchronous communication makes it harder to deal with consumer service failures. We need to think when and how to properly retry failed requests, how not to overwhelm consumer service with too many requests and how to deal with a slow consumer service host. Another option is to introduce a new component that helps to setup asynchronous communication. Producer sends data to that component and exactly one consumer gets this data a short time after. Such component is called a queue. And it is distributed, because data is stored across several machines. Please do not confuse queue with a topic

How Much Does It Cost To Build An Application in 2020

So, how much does it really cost to make an app? I think that question has been asked like five gazillion times, right? And I think anybody who's going to ask me that question again I'm just going to refer to this video. So, in this video, I'm gonna break down the exact strategy to calculate the cost of your app And launch it in the most cost-effective way. So stick around till the end of this video. And hey if you're just meeting my name is Arsh Singh. I'm a growth strategist for entrepreneurs And I help you launch and scale your business using mobile apps

Motivations and Customer Use Cases, Apache Kafka

Let's look at some of the motivations people have for using a system like Apache Kafka, and what are some use cases? What are people in different industries doing with it? (upbeat music) Now, if you're watching this course, you're probably aware that there is a paradigm shift under way in favor of event-driven architectures. The basic idea here is that the way we've been building systems has been focused on state, on the current state of things, and really a focus When we design systems, we focus on data as things. There's very much a paradigm shift underway from that to a perspective of data as events. There are things that happen in the world, and our primary purpose is to process those events. This relates to a lot of different other architectural trends that are happening at the time, but it's a very real thing. And you can see by way of analogy, something like a newspaper, which is a static snapshot of the state of the world as of press time versus like a news feed, all the news tweets if you follow news accounts on Twitter, all those news tweets that might be happening in your timeline. Those tweets are more like events, little discreet descriptions of things that have happened rather than that summary that you'll see in a broadsheet newspaper, which is going to cause us to want a new kind of data infrastructure.

Monolithic vs Microservice Architecture Debate

If you're interested in web development you've probably already heard the monolithic verse microservice debate it's difficult to talk about web apps without this discussion arising well you can create beautiful functional applications with either option it's important to look closely at the two so you can pick out the one that is right for your needs before I give my opinion on them and which one to use I want to give a very basic definition for what a monolithic application is versus a microservice based one monolithic architecture

Microservices - Martin Fowler

My colleagues and friends have been talking about micro services and for me the struggle was to try and figure out well what exactly are they what do people really mean when they talk about microservices and also you know when should we consider using this technique is it new or not do we use it do we not use it and what nerf is it in the first place I mean the basic idea is fairly straightforward you contrast it with what's considered to be a traditional monolithic application a monolithic application means you've got various capabilities various things that you want to provide and you put them all in the same application typically running in a single process

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