Microservices Training | Microservices Docker Example | Microservices Tutorial | Edureka Rewind

Key Takeaways

hello everyone welcome to Eda YouTube channel my name is s and in today's session I'm going to focus on microservice training so without any further Ado let us move forward and have a look at the agenda for today so this is what we'll be discussing today we'll Begin by understanding what the use case that we are going to implement in today's session after that I'm going to tell you about the few Basics which are required in order to execute that use case like what exactly is microservice what is monolithic architecture what is Docker and how Docker can be used in microservices and finally I'm going to tell you how to implement the use case using Docker after that I'm going to discuss the course content of microservices training provided by edua so let's move forward and have a look at the use case that we are going to implement in today's session so this is a problem statement of our use case guys we have a nodejs application and mySQL database running in the same instance or you can say in a local laptop so this is a typical example of a monolithic architecture so let us just focus on few problems with this architecture and then we'll see what is the solution to it so let us now discuss the problems associated with this monolithic architecture I'll just give you a small introduction to all of these challenges later on I'll discuss it once more when I'm talking about monolithic architecture so I hope that is fine with you all so the first thing is large and complex applications so if the size of our application is pretty large and it becomes really complex to understand and modify such applications when you use a monolithic architecture you actually understand that when I'm talking about monolithic architecture in detail you'll understand why are these problem there with such an architectural pattern then it also leads to slow development as the application and the respective teams grow the application becomes difficult to understand and modify and also the larger the code base it leads to slower ID then at the same time it blocks continuous development as well and it is pretty unscalable so each copy of the application instance will access all of the data which makes caching less effective and increase memory consumption and input output traffic also different applications components have different resource requirements for example you know one might be CPU intensive while another might be Memory intensive so with the monolithic architecture we cannot scale each component independently then it is pretty unreliable because of the tightly coupled components that we have here all right so if any of the component goes down the whole application will fail to run and then finally it is inflexible as well so with montic architecture it becomes really difficult to adopt new Frameworks and languages so this is a problem statement of a use case guys let us see what is the solution to such a problem so it is nothing but microservices now what I'm going to do here is I'm going to create two separate Services one called user service another is test database running on a different Docker container all right so with this what we have we have separate services or you can say we have separate microservices compared to a monolithic architecture that we had just seen so what I've done here is this mic architecture where my nodejs and my SQL were running on the same instance I've divided them into two SE separate microservices one is user service and other is test database and both of these services are running on a different Docker container so this is nothing but an example of microservice so this is a use case that we are going to implement in today's session guys if you have any questions or doubts you can go ahead and write it down in the chat box Aura jti soale Adam Dave any questions guys Quinn or Quinn says he has no doubts right now so I can see that few people have raised similar questions jagriti and Puja Even Adam has asked the same question he's asking what exactly are microservices can you please explain with a use case definitely just be a bit patient I just wanted to discuss the use case that we are going to implement in today's session let me just cover all the fundamentals for you so now we are going to compare before and after microservices basically we're going to find out the differences between the microservices and the monolithic architecture so let's begin guys so let's take the classic example of an e-commerce website now from the diagram also we can observe that in the monolithic architecture we have all all the features running out the same instance for example we have customer service we have product service we have card service right all of these instances are running on a single instance and sharing a common database all right so this is a typical example of a monolithic architecture but then with microservices each feature was allotted a different microservice which handles their own data and performs different functionalities all right so this is the basic difference between the monolithic and microservice architecture so the idea behind microservice is that few applications become easier to manage when they're broken down into smaller composable pieces that talks to each other so that is what exactly microservice is now let us move forward and we'll understand microservice architecture in a bit more detail now before this if you have any questions or doubts you can go ahead and write it down in the chat box all right so I have a question from Dave he's asking in microservice architecture the different microservices they share data structures or not well they don't share data structure Dave all right they communicate through apis that's the answer to your question question so I hope you're satisfied with it all right he says thanks any other doubts please write him down the chat box fine so I can see there are no questions let's move forward and we are going to focus on microservice architecture so we are going to discuss it in much more detail so let me discuss this architecture with you now over here we have different clients coming from different devices and they're trying to use services such as search build configure and other management capabilities now all of these services are separated based on their domains and functionalities and are further allotted to individual microservices so you can see we have microservice a b c and d probably this is for your search service this is for your build services for a configure like that we have many other services as well now these microservices have their own load balancer and execution environment to execute their functionalities and at the same time captures data in their own databases so micros service a will have its own load balancer and execution environment and will have it its own database as well similarly for other microservices also so now all the microservices communicate with each other through a stateless server which is either rest or a message BS now the all the functionalities performed by microservices are communicated to the clients via API Gateway when a client gives a request it'll first go to the API Gateway and all the internal points are connected from this API gate so anybody who connects to the API Gateway automatically gets connected to the complete system so I believe guys I've given you a good introduction to what exactly our microservices what is monolithic architecture why use microservices what are the various challenges with monolithic architecture so if you have any questions or doubts you can go ahead and ask me so I have a question from zti she's asking the use case we are going to implement in Windows operating system no we are going to use a cent virtual machine I have it installed in my system and I've already installed Docker in it all right so I'll be using Docker for this particular use case any other questions guys all right there's a question from Puja she's asking what is the relation between devops and microservices so let me tell you a few things first devops is a completely different field it's basically a software development methodology that Bridges a gap between the Ops Team and the dev team and its major aim is to provide good quality software in time and frequent releases if I have to say and without the microservice architecture if you have a large application frequent releases are pretty tough right it there might be certain exceptions but with microservices you can frequently deploy your applications you can quickly adopt changes you can quickly take the feedback and incorporate that feedback and then deploy it again so you know devops methodology with the microservice architecture is something that is really required right now and something that people really appreciate and is highly adopted in the industry right now all right so she's satisfied with the answer fine guys so let's move forward and now we are going to discuss what exactly is Docker now what is Docker if I have to give a definition I would say at its heart Docker is a software which lets you create an image image is nothing but a template for a virtual machine and then run instances of that image in a container so that's what Docker is all right I have a question popped on my screen this is from Quinn he's asking can you tell me the differences between virtual machine and Docker and which is better fine so which is better I would say Docker let me just give you a few reasons for that first of all Docker is pretty lightweight right you have all the binaries and libraries there in your container required for your application which can be a Microsoft service application as well plus it's pretty lightweight plus it doesn't uses the guest operating system it uses the host operating system unlike the virtual machines and you don't have to pre-allocate any Ram in the containers unlike your virtual machines so I believe you I've given you enough differences between the two all right he satisfied with the answer now let me just take you through the diagram that is there in front of your screen so here we have an host operating system on top of that we have Docker engine right so we have couple of applications running on top of Docker engine so we have couple of containers as well all right so basically what we have done we have containerized the two applications in two different containers so we have binaries and libraries along with the application in one container and similarly for the container two as well we have similar configuration so all the binaries and libraries required for an application are present inside a Docker container all right now let me just go ahead and discuss few components of Docker so I'm going to start with what are Docker images and what are Docker containers so Docker images as I've told you are readon templates which are used to create containers now Docker maintains a vast repository of images called the docker Hub which is nothing but a G repository of Docker images now with Docker images we can create Docker containers all right and they contain everything required to run your application now this is all about Docker images and Docker containers so let me just quickly open my Virtual Machine and I'll show you few basic commands of Docker so this is my Cent virtual machine guys over here I've already installed Docker so let me just go ahead and quickly start Docker so the command to start Docker is system CT L start talker so it has started now let me just clear my terminal again and now I'm going to try out few commands and then exit the container so now what I'm going to do is I'm going to show you how you can pull images from Docker Hub right so I'm going to pull open to image from Docker Hub so let me just tell you how you can do that all you have to do is Click Docker pull Ubuntu that's all you have to do it will first check the local system if there are any images available if there are no image is available then it will go ahead and check it in Docker Hub and pull that image for us from dockerhub as you can see that it is pulling from dockerhub right now because it couldn't find it locally so it says that downloaded newer image for Ubuntu latest which means we have successfully download the Ubuntu image now let me just hit a command called Docker PS and this will give me all the images all the containers which are there in my system right now now if I have to run this container what I have to do is I have to type in here Docker run hyphen ID and the name of my image or you can even use the image ID so I am in Ubuntu container right now so over here you can you know try out few docket commands I'll exit from here now and uh yeah so let me just clear my terminal again so what we have done we have basically pulled an image of Ubuntu from Docker Hub and then we buil a container from that image that's what we have done till now let me just show you how dockerhub looks like so for that I'll open my browser now this is the official website that is hub. do.com you need to go to this particular URL and you can just go ahead and create an account for free and get started you can find all the images plus you can upload your own images as well if you want I'm just going to type my username and password I'll be logged into dockerhub so this is how dockerhub looks like guys we have couple of tabs here Repository Stars contributed create a repository create an organization explore repositories so just go ahead and play around with it and you'll understand it I'm just going to tell you how to search an image here so if I want an auntu image so this is the official Ubuntu image here guys similarly you can go ahead and search whatever images that you want all right so let me just close it for now so we have just discussed what exactly is doer what are images and what are containers I also executed practically I told you how you can pull in a bu image and create a container from that let's move forward and we'll focus on Docker registry now I won't spend a lot of time on Docker registry because it is nothing but a storage component of Docker images docker's own cloud repository for Docker images similarly you can have either public or private reposes on Docker Hub as well so it's basically a storage component for all the docker images now I'm going to talk about Docker compose because this is what I'm going to use in today's session now what exactly Docker compose is when you have multiple containers then Docker compose makes it easier to configure and run applications that are there in those containers what I mean by that consider the example that is there in front of your screen so imagine I'm being able to Define three containers one running a web app another running a post gra and a third redis now all in one Yamin file and then running those three connected containers with a single command that's what Docker composes so we have three applications and we write the configurations for all of these three applications we have defined all of these three applications running on different containers in a Docker compos file that is Docker compost. yaml and then with one single command I can run all of these three containers that's what Docker compose is all right so I'm going to show you practically how it works so let's move forward for now now this is basically a use case of how Docker can be used in an industry so I'm going to write a Docker file complex requirements for a micros service in an easy toite Docker file now from that Docker file I can create Docker images and in turn run as many Docker containers as I want now that Docker image I can upload that onto the docker hub from which various teams be staging or production can pull that image and prepare as many containers as they want now whatever was there in my developer laptop is replicated in my staging as well as in my production environment all right or you can say throughout the sdlc so this is how you can use Docker although there are multiple use cases right available so you can just this is one way of using Docker guys now Docker for microservices so just an example how we can use Docker for microservice basically imagine we have separate services for an online shopping service we have accounts service product catalog card servers and Order server right all of them have their own database so we can run all of these services on a different Docker container I'm going to show you practically how you can do that so let me just quickly go ahead and discuss few advantages of Docker in microservices so what are the various advantages that we get when we run Docker with microservices so First Advantage is packaging so a piece of software usually consist of a number of components now these components may be bundled together or distributed separately and I usually themselves composed of various files this can include executables binaries documentation etc etc now in order to make software distribution convenient there must be some way of assembling all of these pieces together into one cohesive hole so traditionally this was done using one of a number of mechanisms like zip files or tarballs deian or RPM packages or language specific packages for example npm python Wheels ruby gems etc etc so these all have their own tradeoffs but they have one thing in common they do not solve the entire problem zip files need an agreed upon format for their contents Debian and RPM packages are os specific and notoriously difficult to work with and the rest are the language specific systems that do a proper job of handling application dependencies outside of the scope of their language now Docker makes it possible to achieve the granity of portable microservices through its packaging so I hope you got my point now let's talk about distribution so in order to share software with others or to deploy it somewhere the software package needs to be tracked in a central place and accessible across the organization now Docker solves this problem by providing a standardized API for a registry Service as well as an open- Source implementation for now the standard Docker registry is not quite user friendly right and lacks some features available in other system such as yam and app however this will improve with time and that will happen definitely guys runtime isolation now if you worry about efficient resource utilization you're likely tempted to run multiple microservices per host all right now this this is definitely doable but can present some challenges let me discuss those challenges so I just discuss one such challenge which is called dependency management for example if service one requires a library with version 1.x while service 2 requires the same library but with an incompatible version 2.x you'll likely run into a problem if you're using a package manager that installs packages systemwide such as apt or yum some ecosystems provide a way to isolate the applications environment into a specific directory one example of this is Python's virtual environment nodejs n PM also does this by default as well however the isolation offered by the system is far from perfect any dependency on libraries or executables outside of the languages sandbox can still result in Conflict another issue that comes up when running multiple microservices on the same host is protection against Rogue processes that use more than their fair share of memory or CPU prior to container technology or Docker containers the main way to achieve this would have been to run multiple virtual machines right now Docker sols this dependency isolation Problem by packaging the entire OS image along with all the dependencies it solves the resource isolation Problem by providing and enforcing explicit CPU and memory constraints similarly docker's runtime isolation allows you to run multiple API microservices side by side on the same host with greater ease and maintainability so different teams working on different microservices will not affect the runtime of others if I have to give you an example think of it like if a revision of an API is needed the API mic MOS service running in a Docker container can be redeployed without affecting other apis and finally the installation process the last advantage of Docker in microsof is it how simple it is to install you can just go ahead and refer a few installation videos you can find the link in the chat box and the people who are watching it on YouTube can find the link in the description box so these were various advantages of using Docker in microservices now let us discuss the implementation of the use case I already told you what I'm going to do here I have a mic architecture that has nodejs and MySQL running on one single instance I'm going to create two microservices user service and test database running on two different containers and I'm going to run those containers using Docker compost all right so I hope I'm clear guys if you have any questions or doubts you can just go ahead and write it down in the chat box I'll be happy to help you any questions guys so we have no questions I'll just quickly open my Virtual Machine and I'll show you how I implemented this use case so this is my Cent virtual machine again guys now for doing local development we we'll need to install MySQL and create a test database for us now for local development we need to install MySQL and create a test database now creating a local database and running scripts on it is an easy start but can get messy lots of uncontrolled stuff going on it might work we could even control it with some shell scripts checked into our repo but what if other developers already have my SQL installed what if they have a database already with creative name users which we want to create so because of all of these reasons we are going to create a desk database server in Docker so I'll just tell you how to do that so this is a great Docker use case guys we might not want to run our production database in Docker but we can spin up a clean mySQL database in no time as a Docker container for development leaving our development machine clean and keeping everything we do controlled and repeatable so in order to do that the command that I'm going to type in here is pretty easy guys let me just go ahead and quickly do that so it is Docker run hyphen hyphen name now I have to give the name to my database so let that be DB then my SQL password I need to give root password which is equal to 1 2 3 whatever password that you want to give just go ahead and do that now Define a port here so36 of my host and 306 of my container as well and the image so I just want the MySQL goon latest image all right so it's pretty easy so here we go so it has started now it is giving us few warnings you don't need to worry about that so this starts a MySQL instance running allowing access through port3 06 using the root password 123 so we know that do current tells that the engine we want to run an image and the name of the image is my SQL colon latest all right so let me just quickly open one more Tab and over here here what I'm going to show you is the image that we have just downloaded so this is the name of our image this is the port plus we have downloaded created about a minute ago right so we can find all the details here now what I'll do now let's connect to this image and see what's there all right so I'm just going to type in here Docker execute hyphen it the name of my image is DB SL bin SL bash and here we go now over here if I type here my SQL hyphen user that is root and the password is 1 2 3 so you can see that so over here I'll just type my SQL databases and semicolon of my SQL database I'm sorry it will be show databases by mistake I've typed my SQL databases so here it is you can see all the information here right so what we did we basically executed Docker exec hyphen it DB tells Docker we want to execute a command the container named DB we can also use the ID or just the few first few letters of the ID as well and hyphen it ensures that we have an interactive terminal MySQL hyphen Ur root hyphen p123 that we have given there is a command we actually run as a process in the container which in this case is just the MySQL climent so we can create databases tables users whatever we need basically now let me just move our this I'll just type in here exit and one more exit all right so we done now so now any questions guys any doubts you have in your mind you can just go ahead and ask me so there are no questions as I can see now running MySQL inside a container has already introduced you know few Docker tricks so we are running MySQL inside a Docker container so now what we need to do is we need to create a test database folder with a script to start the database stop the database and set up the test database so let me just tell you what I'm talking about so I'll just go to a particular directory now we'll have to create a test database folder with a script to start the database stop the database and set up the test data now for that what I'll do I'll just quickly go to a directory that is documents over here I'll enter so this is my application guys let me just clear my terminal now over here I have directory called test database so let me just show you that me clear my terminal so over here I have three scripts one is to start the database that is start.sh another is to stop the database and then the final one is to set up the database as well now let me just show you what I've written in each of these files so let me just start with the startup script start.sh and you can use whatever editor you want you can even use a cat command that will display it on your terminal itself so this is a script to start my test database right it's pretty self-explanatory you can go ahead and have a look at this if you want all of these codes you'll find the link in the chat box right now and if you're watching it on YouTube you can mention your name and the email ID in the comment section below Eda team will send all of these codes ASA all right so this is my startup script now let me show you the setup script that I'm talking about so I'm just going to do a cat command here setup. SQL so this has all of my data so it has my email addresses and various phone numbers and things like that it is available here this is my setup script now what I need to do is I need to create a stop script as well stop. sh so here we have stop the database and remove the container so Docker stop DB and Docker remove DB so before removing any container you need to first stop it and that's what we are doing here as well and then we are removing it RM stands for removing the database now let me clear my terminal so we are done with wrapping up the test database now we need to create a microservices in nodejs so this video basically talks about how we can use microservices with Docker and what exactly are microservices so I won't go into too much detail of nodejs application that I'm talking about so let me just highlight the areas and takeaways so I'll just go to a particular directory called user service and let me just clear my terminal so over here you can see that we have multiple folders and files present here so starting from package.json so this is basically used for dependencies and metadata then index.js is nothing but a main entry point of the application so we have API as well so this API file includes our apis and the API test then we have a config directory as well this is basically the uh includes the configurations of our application then we have the Repository Dory which provides the abstraction over our database and then we have server directory as well that will contain the server setup code this is how we have created the nodejs application let me just clear my terminal again now if you want the code for this application again you can find it through the link that is present in the chat box and if you're watching this video on YouTube you can mention your name and the email ID in the comment section we'll reply you ASAP with the code so this application that I have built here is basically allows us to get all the users or to even search a user using the email so in the setup. SQL file we have seen that we I've given all the data the email address and the phone number so this is what my application is all about it's pretty basic but it's a very good example to understand why we should use Docker with microservices right so now let me just hit few commands so now to start that I'll just use the startup.sh script that I've written and here we go so it is waiting for the database to start up so it is done now we have started our test database all right so in order to stop it we can just use a stop script that is/ stop. sh and that's all we have to do all right so let me just open one more tab here so over here I'll just run my nodejs application so let me first go to that particular directory so all I have to do is here npm install all right so this will set up everything for me so it is up to date in 4.82 6 seconds and the next command is to start my application so all I'm going to type is in here is npm start so server started successfully at Port 8123 now let me just open my browser and I show you how the application looks like this is my browser guys I'll just go to local hostport 8123 slash users so here we can find all the users with their aail ID and phone number so this is how our application looks like guys so now I'm going to tell you how to dockerize our microservices so here we have a microservice which we can run on a development box as long as it has a compatible version of nodejs installed what we would like to do is set up our service so that we can create a Docker image from it allowing us to deploy our services anywhere with supports Docker and one way to do is to create a Docker file so as I've told you earlier as well during the use case that we write complex requirements for a project or a micros service and an easy to write Docker files so this Docker file is what I'm talking about right now so Docker file is recipe that tells Docker engine how to build your image we'll create a simple Docker file in our user service directory and start to explore how we can adapt it to our needs so I've already done that let me just quickly show you where it is present so so I'll just quickly go to that particular directory where I've already written that yeah let me just hit an LS command and you can find that we have test database and user service here as well apart from that we have a compose yaml file and integration test which I'm going to tell you about later you don't have to worry about it right now let's just talk about Docker file so we'll go to this user service all right so let me just go there clear my terminal and you can see that we have a Docker file present here as you can see that we have a Docker file present here so let me just quickly show you the contents of this Docker file so what we have done here first of all we are telling Docker to use node 4 as a base image CMD command tells Docker that this image should run the node executable when the executable terminates the container shuts down then what we have done we have made use of add command to copy everything all right so you can see that we have an add command here to copy everything in the current directory to a folder in the container called app we then use run to run a command in this image in the image which installs our modules and finally we expose the server Port 8123 telling Docker we intend to support inbound connections on 8123 then run our server code so this is how our Docker file looks like now let me just go ahead and close it similarly I've written the docker file for my test database as well so let me just quickly go to that particular directory so here in the test database we can currently see when we hit an Lis command that we have two files one is Docker file setup. SQL file but I have actually told you to create start.sh and stop Dosh as well along with setup. SQL there was no Docker file so now that we are not familiar with Docker we can improve on this looking onto MySQL image documentation on the dockerhub there's a note which tells us that do SQL orsh file added to the images folder will be executed when setting up the DB so what I have done basically I have replaced my start.sh and stop. scripts with Dockery all right so let me just quickly show you how the docker file here looks like it's pretty easy although uh let me just open it through gedit so use MySQL 5 as my base image after that I've given the password for my database then the name then the service and then the MySQL password password is 1 2 3 add setup. SQL to Docker entry point IIT d b. D so over here I've just written that to use MySQL 5 as my base image then provided the root password database name user service then we have provided the MySQL password and then we have used the add command let me just quickly save it and close it so that was pretty basic guys writing a Docker file now once we have written these Docker files what we can do is we can make use of a command called Docker build hyphen T Test database so Docker build hyphen T Test database so this command Docker build hyen T Test hyphen database will actually build a new image from the docker file that you can see over here right so it will build a new image from that particular Docker file similarly if I type in here instead of build if I type in here run hyphen it test database so this will run a container with this image all right so it will basically run a container with this image the previous command that I've showed you will build an image from the docker file and this will run a container from that particular image this is why we use Docker files let me just quickly go ahead and clear my terminal and now I'm going to talk about composing so building and running each container is still somewhat you know time consuming we can take things a step further with Docker compos tool which I've discussed during the slides as well so docket compos lets you create a file which defines each container in your system the relationship between them and build or run them all if you're facing any difficulties in installing Docker compos I leave a link in the chat box people who are watching it on YouTube can see the link in the description box below now what we need to do is create a new file in the root of your project called Docker hyphen compost. yaml so it's a yaml file let me just go back and hit an LS command here and you can see that we have Docker hyphen compost. yaml file present so let me just quickly take you through that particular file I'll use gedit in order to you know open that file you can use whatever edit or or you can even use a cat command to open that on the terminal let me just increase the size of it yeah so I've written all the docker files that I first want to build and create an image and linking the different Docker images or the docker container so you can see that I have Services here user service and build will basically I need to specify build value for each of our service tells Docker where to go and find that particular Docker file so the first one is do/ users hyph service the name of the container is user undor service and the port that is present here it should be linked to my database right depends on the data database environment is database uncore host is equal to DB similarly my database image can be built using the docker file which is present in testore database so it is pretty basic let me just quickly save it and close it let me just clear my terminal again so I need to sign in as a root user so for that I'm just going to type in here the password so now what I'm going to do I'm just going to type in here Docker hyphen compose build so this will build the docker images for me so it is successfully built now let me just clear my terminal and now I'm going to run this application so for that I'm going to type in here Docker hyphen compose up that's all I have to do and here we go so server started successfully running on Port 8123 so let me open my browser and check whether it's working or not Local Host 8123 SL users so as you can see that application is working here here I have all the email IDs and the phone numbers which are there in my setup. SQL file so by this we come to the end of this use case let me open my slides and I'll continue from there so Eda provides online structure training on microservices you can find the course content in front of your screen and for rest of the details I'll quickly open my browser and I'll show you the course landing page for microservices so this is the website guys that is ./ microservice architecture training over here you can find all the details like the upcoming batches what is the course curriculum course description project certification reviews and then even the course fees pretty much everything related to the course you can find it here for all of those who are watching this video on YouTube you can mention your email ID in the comment section if you're looking for structured training on microservices thank you and have a great day