AWS Applications Deployment Basics – Part 2 (Setup NGINX)

Introduction

In the previous post of this series “AWS Application Deployment Basics”, we setup a PostgreSQL database and then we connect to it via a Nodejs application.

However, the Nodejs application is running on the same machine and database access is local for it. It is a totally valid setup and because it is on the same machine, the access is straight forward. But, have applications and databases running on separate machines is also a very common setup and we will cover that path as well later in this series. But today, we will focus mostly on the web server we want to run on an EC2 instance in public subnet.

If you remember our VPC setup, we have a public EC2 instance as well, which we are currently using as a Bastian-server (aka jump host) and as a NAT instance well. Now, the Idea here is to use it as NGINX web server as well. This is an Amazon Linux EC2 instance.

Now in real world, you might want to run NGINX on a separate EC2 instance, however, the process is same and just to save some time and cost I will just use already running EC2 instance (public subnet) for this as well.

Architecture Diagram

Here is the updated diagram which shows the NGINX we will be setting up.

Installing NGINX on Amazon Linux EC2

1. SSH to bastian server (public Amazon Linux EC2 instance)

ssh -i ./fm-keypair.pem ec2-user@ip-address-machine //SSH to Bastian Server

2. Update Packages on Amazon Linux

sudo yum update // (ubuntu) sudo apt-get update

3. Install NGINX on Amazon Linux

sudo yum install nginx // (Ubuntu) sudo apt-get install nginx

4. Test Installation using bash

Cool. installation is done and lets do a small test to confirm that it is working.

nginx -v
sudo service nginx status

here is the output of action:

Accessing the Web Server

NGINX typically comes with a default website and config file which is configured to deliver the default website.

So, let’s try to access this website locally using curl:

You can see that we received HTML of the default website. Actually if we see the security group we attached with this instance:

You can see the security-group already have Inbound HTTP rule configured and actually I can access this web page from anywhere in the world, let’s try to access it using Elastic-IP of Bastian-host (same EC2 with NGINX) in the web browser:

Connecting NGINX with Node.js application

Let’s do a simple test. We will connect NGINX with Node.js application by using NGINX reverse proxy capability:

So, this way, we shall be able to get products data in postgreSQL.

Prepare NodeJS application

We will be using PM2 to run our Nodejs application. PM2 will keep running node server in the background.

Install PM2 on EC2 in private subnet (where Nodejs application is running and Run app)

1. ssh to ubuntu EC2
2. sudo npm install pm2 -g     // Install pm2 
3. pm2 start server.js    // Run the Server app

here is output:

Other relevant commands for pm2 are as follows:

>> pm2 stop server.js
>> pm2 restart server.js

You can look for more commands on pm2 website.

Let’s see the security groups attached the ubuntu EC2 machine in private subnet:

So all traffic from public subnet is allowed. One more test I want to do at this point is to see that if I can access Nodejs application from EC2 instance which is in public subnet (bastian host)

you can see, as expected that we are able to communicate with Node app (which is running on private EC2 port 3000) from the public EC2 machine.

Next let’s setup NGINX reverse proxy next.

NGINX Configuration

I will try to keep details simple and basic. You can find more info about various configurations online. I also wrote a post on this topic you can look on this link.

Let’s update the nginx config file for proxy configuration:

sudo nano /etc/nginx/nginx.conf

This will open the configuration file in nano editor. Scroll down until you see a server block, there we need to add location and proxy_pass information for our node application as follows (notice the private IP address of ubuntu EC2 machine running nodejs app on port 3000):

location /nodeapp/{
   proxy_pass http://10.0.2.99:3000/;
}

Here is the config file of nginx on my public EC2 instance.

press CTRL+x to save and close the file. Restart the NGINX service.

 sudo service nginx restart

Now, let’s try to access the node application endpoint using browser:

and you can see that we are able to receive the data as expected.

Following is the update diagram of current workload:

NGNIX is a light-weight and easy to use web-server. If you like, you can actually introduce multiple location block and proxy call to different services running on different EC2 instances.

Summary

In this post, we setup NGINX on EC2 instance in public subnet. We then make a reverse proxy configuration to pass request to Nodejs application from previous post and because that application can connect to the postgres database, we able to access the data over HTTP.

This is a very basic, common setup with a webserver, application and database and in next posts, we will be adding more applications, configurations and enhance this design as needed. Let me know if you have some questions or comments. Till next time, Happy Coding.