Robert Tod

@bobtodski

Tutorial: Creating and managing a Node.js server on AWS, part 1

Intro

There are many ways to run servers and plenty of cloud platforms to do so. To start this tutorial series I am going to go with managing an EC2 server using AWS (Amazon Web Services), which is down to the metal and probably the most common way to run Node.js applications.

This tutorial series is intended to help get a better understanding of cloud based servers, though there will be small parts showing how to set up a simple Node.js app.

I find that most tutorials for configuring AWS or cloud servers often expect quite a bit of knowledge and can be quite daunting. For the most part there is quite a bit of reading between the lines to get through. I hope that this is quite simple to follow. To make it as simple as possible I will be writing it with Mac users in mind but if you are using Linux then it won’t be much of an issue, we will just be using bash and a text editor.

This part will cover

  • starting an AWS server
  • SSH into your server
  • installing Node.js
  • creating a public HTTP endpoint that responds with a static message

Creating and starting the server

If you haven’t created an AWS account, open https://aws.amazon.com/, and then choose Create an AWS Account. Follow the steps to get an account setup.

Once logged into your AWS account we are going to create an EC2 machine. EC2 stands for Amazon Elastic Compute Cloud. The compute cloud is just a load of computers in Amazon’s datacenters that are connected to the internet and can be controlled by using the AWS dashboard. We are going to take one of those machines and set it up for our use.

Click services on the navigation bar and select EC2, which is under the compute category. Click launch instance. You will be presented with a bunch of options which are various different images. An image is an exact copy of a hard drive that can be easily loaded onto an empty hard drive, in this case they are being used as presets to get your machine setup easily. Without at least an operating system and SSH, it wouldn’t be possible to even configure the instance so some preset software is necessary.

Selecting an image

The options include different versions of Windows and Linux. Most servers run Linux and it is a great choice for developing Node.js, Windows servers are only really useful for specialized applications such as .NET *shudder*. For the basic things we will be doing in this tutorial, there isn’t much difference between the Linux images. I chose to go with Ubuntu Server because it is widely used and has tonnes of guides and plenty of questions and answers on Stack Overflow.

Once an image has been selected, we need to select an instance type. Notice that this is a virtual server, with virtual CPUs. Virtual means that although it will seem like we are connecting to and configuring one computer, in fact Amazon will be running multiple instances on the same machine while pretending it isn’t, which is great for scaling and pricing. Let’s choose t2.micro which is eligible for the free tier, so if your account is less than 12 months old you can run your server for free. Thanks Amazon!

Selecting an instance type

After you have selected your instance type, click Next: Configure Instance Details. The following page is more complicated but you can ignore most of it for now, we may explore these options later.

Click Next: Add Storage. The default is 8GB of an SSD which is fine for us. Click Next: Add Tags. We don’t need any tags but they are useful for when you have a large number of instances and you need to filter and search through them.

Click Next: Configure Security Group. A security group is a config for your server, telling it which ports it should expose to which IP addresses for certain types of traffic. Name the group something meaningful, I chose tutorial group.

To run our app we are going to need SSH access, which by default is on port 22 and uses the TCP protocol. Amazon adds this in for us by default. There is a warning about the source being 0.0.0.0/0 which allows us to SSH from any IP address however this is fine. If you were deploying and configuring your app from a VPN or company network then you could limit SSH access only for that IP which is a good security precaution when running something in production, but SSH access requires the correct SSH key so it is completely secure without this measure.

Since we would like to also serve an app we need to expose a HTTP port publicly, by default this is port 80 (but browsers strip this so you don’t see it in URLs). Click Add Rule and select the type as HTTP, the default settings for this will use TCP as the protocol and expose port 80 to all IPs.

Configuring a security group

To launch the instance, click Review and Launch, then click Launch. You will be prompted to setup an SSH key which will give you access to the instance. Choose create a new key pair, and name the key, I named it “tutorial”. Click Download Key Pair. This should download a .pem file which can be used to SSH into the server. Keep this file safe because anyone can connect to your server using it, if you lose the file you will need to generate a new one.

Click Launch Instance. Click View Instances. Woo! Your instance should be booting up. Once the Instance State is Running then you are ready to SSH in.

Note: Remember to stop the instance when you aren’t running it! To do that just right click on the instance, under Instance State click Stop.

Stopping an instance

SSH into your server

Generally, the correct place to put your .pem file is in your .ssh folder, in your user directory. The .ssh folder is a hidden folder, to open it in finder open terminal and execute the open command.

# The open command will open the
# given path using the default system
# application for the file type. For
# folders it uses finder!
$ open ~/.ssh

Once the .pem file is in your ssh folder, use chmod to set permissions so that it can be used as a key.

$ chmod 400 ~/.ssh/whatever-your-key-name-is.pem

To SSH we need to have a username, an address and a key. The address is available when we click on our instance in the EC2 instances dashboard.

Instance details

The instance I setup has a public IP 52.214.64.31 which I could use to connect, giving the .pem file as a key using the -i flag.

# Don't actually run this command
$ ssh -i ~/.ssh/whatever-your-key-name-is.pem 52.214.64.3

However it is more correct to use the public DNS (the only real difference though is when you are connecting from EC2 machine to EC2 machine then the DNS will resolve to the private IP rather than the public IP).

# Don't run this command either
$ ssh -i ~/.ssh/whatever-your-key-name-is.pem ec2-52-214-64-31.eu-west-1.compute.amazonaws.com

Almost there. By default, connecting to your instance without a username will try to login as root which is generally not allowed. By right clicking your instance and selecting connect we can see what the correct username is. This is dependant on the image you chose, for ubuntu the username is by default ubuntu. You can see the username in the Example section of the dialogue, it is the part before the @ symbol.

Finding the SSH username

To connect, the SSH command should look something like

# Fill in your specific details for this to work.
$ ssh -i ~/.ssh/whatever-your-key-name-is.pem ubuntu@ec2-52-214-64-31.eu-west-1.compute.amazonaws.com

This should connect you to your instance, just type yes when prompted so that you can add your instance as a known host. You’re connected!

Installing node and system dependencies

Once in an SSH session the first thing to do is get Node.js. NVM (Node Version Manager) is a pretty great way to install Node.js and allows you to easily switch versions if required.

To install NVM just run this command (same as in the NVM installation instructions).

$ curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.32.1/install.sh | bash

This command pulls down a script from a remote URL and runs it. You now have NVM! But if you run nvm ls you will notice it isn’t found. This is because NVM adds some code to your ~/.bashrc. This file is a special file that is run every time you log in to your instance, so to get NVM running you could logout and login again. However you can just run the file manually by using the source command.

$ source ~/.bashrc

Now running nvm ls works! But there aren’t any node versions installed! To get the latest version, just nvm install <latest version number>.

$ nvm install 7

To check node is ready to go just echo the version.

$ node --version
Installing node

Node.js is installed!

Creating a public HTTP endpoint

Before concluding this part of the tutorial we are going to make a public URL anyone can request from the browser to get a response from the server.

Make a directory for the server and cd into it.

$ mkdir server
$ cd server

Now you are in your server directory, you need to npm init

$ npm init

This will create a package.json file which will be used to track any dependencies we use. npm init will ask for a load of info, I tend to just press enter to use all the defaults.

All we will need to run our server is the express package. To install express and add it to package.json.

$ npm install express --save-dev

Note that now you should have a node_modules directory and package.json

$ ls

Now we just need to add some code to run the server. We will use nano to write the server in an index.js file.

$ nano index.js

The server I used just responds with “HEY!” when you do a request to /. I listen to requests on port 3000.

const express = require('express')
const app = express()
app.get('/', (req, res) => {
res.send('HEY!')
})
app.listen(3000, () => console.log('Server running on port 3000'))

Press ctrl+x to exit, ensuring you save when you exit by pressing y followed by enter.

Now we can use node to start the server!

$ node index.js

Once listening, this should log “Server running on port 3000”. You may have noticed however we didn’t open our server traffic to port 3000, we opened it to port 80. Port 80 is a privileged port and running the server there using Node.js is unusual, generally using a router is better. If you change the index.js file to use 80 and then run node index.js you will notice you get a permission denied error.

In the next tutorial we will go through adding a router to use port 80, but for now let’s just open up port 3000 so we can test our server.

Leave your server running and go to the Security Groups tab in the EC2 console. Right click the security group you setup and click edit inbound rules. Click Add Rule. This time we are going to use a custom TCP rule on port 3000, open to anywhere.

Opening up port 3000 to TCP traffic

Click Save. We should now have access to our server! Using a browser, visit your public DNS URL with port 3000 and you should see the HEY! response.

The response from your server

To leave the server running when we log out, we need to press ctrl+z to pause the process (this only works when your server is running, node index.js). When you press ctrl+z you will be presented with all jobs, in this case the only one there will be the Node.js job that was paused.

You can see that the job number for node index.js is 1 (as noted by [1]+). To run that in the background, use the bg command.

$ bg %1

Then logout

$ exit

You should still be able to access your URL and see the “HEY!” response.

Conclusion

If everything went well we should have a simple Node.js app which is accessible from a public URL anywhere in the world!

To stop the instance just navigate to the Instances tab in the EC2 dashboard, right click on your instance and in Instance State click Stop.

In the next tutorial I intend to cover

  • running the app on port 80 using nginx
  • using PM2 to keep the app running after a restart
  • using PM2 to deploy the app from a local directory

Let me know in the comments section if there is anything I missed or is a bit confusing!

Part 2 is now available.

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