What are Microservices | Microservices Architecture Training|Microservices Tutorial | Edureka Rewind

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hello everyone welcome to Eda YouTube channel my name is s and today I'm going to discuss about what are microservices so without any further Ado let us move forward and have a look at the agenda for today so these are the topics that we'll be covering today we'll Begin by understanding why we need microservices right everything exists for a reason so we'll try to figure out why we need micro Services right then we'll focus on what is microservice architecture and what are its various features then we'll understand various advantages of microservice architecture and we'll look at companies using microservices and finally there will be a demo based on microservices in which we'll have three services that will be communicating with each other so let's move forward guys and focus on why we need microservices so before microservices we all know that there was an architectural pattern called monic architecture that was used all right so there are certain disadvantages of that architecture but let me first explain you that architecture what exactly monolithic architecture means so basically in this the entire software is composed in a single piece that is designed to be self-contained so what I mean by that basically all the components of a monolithic program are interconnected and interdependent or in other words if I have to put it I'll say that it will give you a tightly coupled software where each component along with its Associated components must be present in order to execute or compile the code so all of these components are actually depend on each other so if you notice the definition that is there in front of your screen it says that mtic architecture is like a big container right think of it as a big container wherein all the software components of an application are assembled together and tightly packaged right so if you notice that there is an example in front of your screen so there's a server side application right which executes a domain specific logic it will retrieve and update data from the database and at the same time populate the HTML views to be sent to the browser so it is basically a big container or I can say that it is not divided into small small services or not divided into small small components so even these components that are there are pretty tightly coupled right so I'll give you a better example of what exactly monolithic architecture is let me just move forward so let us discuss a classic example of an e-commerce website like Amazon or flip cart all right so everyone actually visits uh these websites quite often so that's a perfect example to you know explain you so let's understand what monolithic architecture exactly means with this example so as you see that in basic e-commerce application we have common option of customer service right product service and card service which a customer can access through their browser right and when you launch the application it is deployed as a single monolithic application there's only one single instance if you can notice so we have customer service product service and card service and when you deploy all these Services it will be basically a single monolithic application now what you can do is in order to scale it you can run multiple instances of this application behind a load balancer right now let me discuss few advantages of this application so first of all it is very very simple to develop right as a goal of the development Tools in IDs is to support the development of Monolithic application it makes the development really easy and one directional all right now it's pretty simple to deploy because you have to deploy the executable file at the runtime to launch the application that executable file can be award file as well now it is pretty simple to scale as well because uh you know in order to scale your application all you have to do is run multiple copy of the application behind a load balancer now since everything comes with its pros and cons mtic architecture also has few major drawbacks let's discuss about them one by one the first disadvantage is large and complex applications now if you have a large application or you can say with the increase in size of the application it becomes really complex to understand and modify such applications right and as a result development slows down and modularity breaks down over time moreover because it can be difficult to understand how to correctly Implement a change and due to that the quality of of code declines over time let's see what is the next disadvantage so the next disadvantage is slow development so what I mean by that as the application and the respective teams grow the application becomes difficult to understand and modify right because it's pretty huge in size and there are multiple teams working on it so it becomes really difficult to understand and modify also the larger the code base leads to slower ID which makes the developers less productive so the code base is pretty large because the entire application is one monolithic application right there are not different different services present now it blocks continuous development so what I mean by that a large monolithic application is an obstacle to frequent deployments let me tell you how in order to update one component you have to redeploy the entire application which interrupts the background task so if I have to take the example of the e-commerce website if I have to update the card service I have to redeploy the entire application the entire application which includes the customer service the product service all these Services right so there's also a chance that components that haven't been updated will fil fail to start correctly all right because of many dependency issues or anything right and as a result the risk associated with redeployment increases which discourages frequent updates I hope you're getting my point let's see what we have next so the next point is unscalable I know I've told you that it's pretty easy to scale but let me tell you what are the disadvantages when it comes to scalability and in terms of Monolithic architecture so each copy of application instance will get access to all of the data right which makes caching less effective and increase memory consumption a with input output traffic also different application components have different resource requirements one might be CPU intensive right while other might be Memory intensive uh and with the m architecture we cannot scale each component independently right so if you can see the example that is there in front of your screen so here we have customer service product service and guard service this is one instance and this is how we are scaling it right if I have to increase only the customer service I have to scale up the customer service I have to do that for product and card service as well right now it is pretty Prett unreliable as well let me tell you how so because of the tightly coupled components if one of them goes down the entire system will fail to run what I mean by that if one of my say product service fails that will in turn lead to the downfall of my entire application right and because all the modules are running within the same process a bug in any module can potentially bring down the entire process more however since all the instances of the application are identical the bug will impact the availability of the entire application this makes the monolithical architecture highly unstable and unreliable the last and the final point is inflexible so how is it inflexible guys with the mic architecture it becomes really difficult to adopt new Frameworks and languages suppose you have million lines of codes written with XYZ framework now it would be extremely expensive in terms of time as well as cost to rewrite the entire application to use the newer ABC framework right even if that framework was considerably better and as a result there is a huge barrier to adopting new technologies I hope you're getting my point so why is it very expensive because you know you have written million lines of code in some language now you want to use some other language right so it becomes really expensive and a timec consuming task and even if the new language of the framework is considerably better but you know there's a huge barrier in adopting such new technology so I hope you have understood the various disadvantages of monic architecture now is a time to understand what exactly is microservice architecture microservices also known as microservice architecture is an architecture style that structures an application as a collection of small autonomous Services modeled around a business domain now if have to put it in simpler terms basically it is a self-contained process which avails different and unique business capabilities now if you have large applications built using this architectural pattern it can be broken down into small multiple Services which together acts as one large system but behind the scenes it's a microservice so what I'm trying to say here is we have multiple services on all of these Services they don't share the data structure but they'll be communicating through apis right the major advantage of breaking down the system is now each microservice can focus on only one single business capability which definitely leads to a better quality anthrope and it's obviously becomes easy for you to understand when I explain you with a example again I'm going to take the e-commerce side example now if you remember in monolithic architecture all the components were in a single module but if you see here with microservice archit all the components are divided into separate modules which communicate with each other using a well- defined interface usually rest or messaging now the communication between the microservices is a stateless communication where each pair of request and response is an independent transaction and because of this microservices can communicate effortlessly more however in microservice architecture the data is Federated all right so let me just break it down for you each micros service is responsible for its own data model and data because of which interaction with each microservice is handled by different instance unlike in monolithic architecture where we had only one instance here we have multiple instances for different different microservices so we have three microservices here customer microservice product microservice and cart microservice right each of them have their own instances they have their own data model and they have their own data so this is what exactly microservice architecture is now let's dig a bit deep into its architecture and understand what it is now as you can see in a microservice architecture services are small and independent and Loosely coupled so let me just tell you where it is so these are multiple Services right so these are pretty small in size and they're independent and Loosely coupled now each of these Services have a separate code base which can be managed by a small development team and it is deployed independently right so this service will have a code base this service will have a code base this service will have a code base similarly all of them will have a code base which will be not huge in size when you compare it with a montic architecture where all of the services are running in one instance I hope you're getting my point now basically a team can update and an existing service without rebuilding and deploying the entire application for example if I have to update this particular service I don't have to do it for the other services as well I can just redeploy the service independently now services are responsible for persisting their own data or external State internal implementation details of each services are hidden from other services more they don't need to share the same technology stack libraries or Frameworks as well right you're getting my point so they might not have the same technology or same libraries or the same framework and they have their own database and things like that so they are pretty independent from each other besides for the microservices themselves some other components appear in typical microservice architecture so let me just discuss that so the first part is management so the management component is responsible for placing services on nodes identifying failures rebalancing Services across nodes and so forth right then let's talk about service discoveries now service Discovery the task of this uh component is to basically maintain a list of services and which nodes they're located on it enables service lookup to find the end end point for a service let's talk about API Gateway now right so API Gateway is basically the entry point for clients so this client won't call all these Services directly right it will first go to this API Gateway which will forward the call to the appropriate services on the back end right if I'm a client I'll request for this particular service then I have to call the API Gateway and which will in turn call the service on the back end now the API Gateway might aggregate the responses from several services and return the aggregated response now it might be possible Right a client request from multiple services so at that time it will aggregate the results from various services and will return the aggregated response right so I hope I am clear with the architecture let us focus on what are the features of microservices architecture the first feature is small focused so what it means it means that the aim of microservice Architecture is Simplicity you know so that it can be Rewritten and maintained without any extra efforts by the development team right that's what I mean by small focused then the next point is Loosely coupled so as I've already mentioned multiple times that each microservice is independent of each other and do not need to coordinate as well this makes the development as well as the deployment real quick guys right so if I have to update a particular service I'll only update that service I won't uh you know update the other services right so that way deployment becomes really quick so that's the big Advantage now let's talk about language neutral so to be a good micros service it must be language neutral so what I mean by that for example in an application if you Services can be written in Python for fast deployment whereas few might be written in Java because it's speed and extensive libraries right so depends on the micros service what kind of programming language we are using so it doesn't really affect the other services right now bounded context so it means that each microservice doesn't need to understand the implementation of other microservice so these are few features of microservice architecture now let's talk about various advantages of microservice architecture now the firstly independent development so so each microservices can be developed independently where a single development team can build test and deploy a service I I think I don't need to explain this much independent development means if I have a product service and I can independently focus on product service where a team of developers are writing code for that particular service testing it and deploying it now independent deployment means that you can update a service without having to redeploy the entire application bug fixes and feature releases are more manageable and less risky as well because you have to focus on one particular service you have to deploy or update one particular service you don't have to care about the other services or the entire application as such right so next is Fault isolation so it is a very big Advantage guys basically if a service goes down it won't take the entire application down with it for example if my card service goes down my entire application is largely unaffected unlike the mic architecture where if one of my component goes down the entire application fails to work next is mixed technology stack because of this feature teams can pick any technology which fits best for their service right and last but not the least granular SC scaling which means that Services can be scaled independently unlike my M architecture where you know I have to deploy multiple instances so in order to scale here I can only scale a particular service if I have to you know increase the card service then I can just scale up the card services instead of scaling up the entire application so let's move forward so there are a lot of companies which are using microservices we have Amazon Netflix SoundCloud Twitter Uber PayPal lot of companies right and why this happens because large applications become easier to manage when they're broken down into small composable pieces so without any further delay let's begin with our Hands-On we'll be using spring boot because it provides a way to provide Java applications quickly and simply through an embeded server and by default it is version of Tomcat it will basically eliminate the need of java containers and with spring boot we can expose components such as rest Services independently exactly as proposed in the microservice architecture that we have just discussed in any maintenance of the components we no longer make the redeploy of its consumers I'll tell you what exactly I mean what is a consumer for this lab we'll use Eclipse oxygen and Maven 3 now to illustrate the concept of micros service what we'll do we'll create three Maven projects in this handson and each of them will symbolize backend functionality or you can say reusable apis and one of them held a composition if I have to put it in simpler way I will say it will be a consumer of the other two so one application or one service will be a consumer of the other two Services right so we'll be creating three simple Maven projects that I've already done I'll just open my clipss and show you that so my first Maven project is basically diagnosis microservice then we have doctor microservice and we have patient microservice so this doctor microservice is the consumer right and uh consumer of the other two microservices that is patient and a diagnosis all right so uh that is how it is done now if I have to explain one of these Services let me explain you the patient micros service first so over here as you can notice that we have a pom.xml file so basically this p .xml file will establish all the dependencies right before we start coding the first class that we create that we call application will be identical in all three project and uh it only works as an initiator to Spring boot that we call as spring boot application annotation so that's how it is if you notice here we have application. Java so it will be common application. Java and application configuration. Java are the two packages that we have created will be common for all the other microservices as well so if I show you for doctors as well so here also we have application. Java and application config do Java similarly for diagnosis as well if you notice we have both application. Java and the other things as well now we have patient. Java and we have patient rest. Java right so the patient. Java here we have defined all the variables like you know the email ID of the patient name and things like that and this patient rest. Java will be used to provide the input to the variables I hope you're getting my point patient rest. Java is basically to provide the input I won't be explaining the code here in the upcoming tutorials I'll be explaining the entire microservice you know how the code works and and everything all the technical details you can find in the next tutorial and this I'm just giving you an overview of how things work in microservices and we have this application config class as well right uh the package so let me tell you why we actually use it is basically it is a resource configuration class which is basically a resource manager responsible for exposing rest services for application consumers right so basically for messaging right so the rest service is for messaging and it is a stateless service for application consumers and we can notice that patient. Java and patient rest. Java are in the same package right now let me tell you how I've defined the ports here so all I have to do is right click go to properties click on run dwor settings and when I go to arguments right so I just have to write minus D ser. Port 8081 so you can see that my patient micros service will be running at a port 8081 when I started let me just start all of these Services one by one so I'll start this first just click on uh run as spring boot app similarly click on right click on this and I'll just uh run it as spring boot app again and I'll run this also as a spring boot app so it is done now let me just open my browser all right so this is for Port 8081 right so my port 8081 is for patient so let me just click over there let me reload this page again so here I have my patient microservice similarly my port 8082 is for diagnosis right so here I have the diagnosis microservice and finally my port 8083 basically is a consumer all right it's a doctor microservice and uh in the URL if you notice I have written patient ID right uh diagnosis and consultation right so basically we'll get you know this particular page patient has been diagnosed with this disease and this is the consultation right so let me just uh reload this again for you so I can just go ahead and change the diagnosis as well I can make this as two right so Rachel has been diagnosed with a different disease now similarly if I make it as one she has been diagnosed with viral fever here right so that is what the difference is basically this particular microservice is a consumer of the other two Services right so you can even think of it as an e-commerce application I know it's it's not of that level but consider it something like you know customers products and orders so this patient micros service will become the order microservice right and the other two will become customer and products so this order microservice will be a consumer of the product and customers similarly in this example we have patient and doctors we have patient microservice and we have diagnosis microservice and we also have a doctor micros service which is actually a consumer of the other two service so by this we come to the end of this video edura provides online structur training on microservices as well so if you want the detailed course curriculum you can go ahead and mention your email ID in the comment section they will reply you ASAP thank you and have a great day