About Deploy a simple node js app on EC2 ( Elastic Compute Cloud ) AWS instance.

Steps followed:

Part A)

1/ Install the nodejs on Linux machine with -> sudo dnf install nodejs 
2/ Run the commands to check installation status & version :
        node -v
        npm -v
3/ Create a node.js app named simple-nodejs2.js and run it on local machine using below command : 
        node simple-nodejs2.js
It won't give any output on terminal, so go to browser and type http://localhost:3000 to test if it display output.
4/ If you get an error message like below means port 3000 is already being used by other service. So check which service is using that port :

    throw er; // Unhandled 'error' event
    Error: listen EADDRINUSE: address already in use :::3000 
    and so on...


        ss -tulnp | grep 3000          # This will display PID of service using 3000 port
        kill -9 257157

5/ Run the app again and it should works. Once nodejs works on local machine next is to deploy on AWS from the Github.

Part B)

1/ Clone below repository to your local machine or you can create your own repository too.

        git clone https://github.com/yoginderbagga/nodejs.git
        
2/ Create a text file and add the code of your node.js [ simple-nodejs2.js ]  
3/ Next go to AWS Console -> Select EC2 Instance -> Launch an Instance and fill below details : 

        Name and tags                                     : Enter the name of your Instance
        Application and OS Images (Amazon Machine Image)  : Select Ubuntu
        Amazon Machine Image (AMI)                        : Select Ubuntu Server ( Free Tier Eligible )
        Instance type                                     : t3.micro ( Free Tier Eligible ) 
        Key Pair                                          : Click create key pair and fill details. Select .pem and give a name.
        Network settings                                  : Check the "Allow SSH traffic from" option 0.0.0.0/0 ( Since its a test envirionment choose the option. Be careful if you need to allow SSH from specific host ) and click "Launch an Instance"

4/ Select the instance which is created and click "Connet" button. Next, go to terminal on your local linux Laptop and connect with AWS Instance using SSH
        ssh -i my-key4.pem ubuntu@44.192.X.X        # Replace the IP Address with Public IP displayed in EC2 Instance.
5/ Run below command to clone the git repo and install nodejs on your ubuntu AWS Instance

        ubuntu@ip-172-31-67-215:~$ git clone https://github.com/yoginderbagga/nodejs.git
        sudo -i             [ To install it as sudo ( root user ) ]
        apt update
        apt install nodejs
6/ Finally run node js app from the EC2 Instance and try to access it from your Local Machine 
        node simple-nodejs2.js
   On browser type type Public IP of your EC2 instance with port number, http://44.192.252.146:3000 
   You may not get the output and receive the error message. Its because the port needs to be bind with the public IP.
7/ Go to "Security" in EC2 Instance, search for "Inbound rules" and add a new inbound rule there to allow the port to be bind. 
        Add port range = 3000 and type Custom TCP ( default selected ) and source = 0.0.0.0/24 
8/ Test from the local machine again, http://44.192.252.146:3000 and its good to go.

Envirionment:

Any Linux OS  [ I am using Fedora Linux for Local machine and Ubuntu on AWS EC2 Instance ]
AWS 
Nodejs & NPM

note : First try to running the same application on your local host machine to check syntax and all is correct and then deploy on the AWS.