How to Set Up Nginx on Ubuntu 18.04


Nginx is one of the most popular web servers in the world and is responsible for hosting some of the largest and highest-traffic sites on the internet. It is more resource-friendly than Apache in most cases and can be used as a web server or reverse proxy.

In this tutorial, you'll learn how to install Nginx web server on your Ubuntu 18.04 server.


Prerequisites
Before you begin this tutorial, you should have a regular, non-root user with sudo privileges configured on your server. You can learn how to configure a regular user account by following our basic server setup guide for Ubuntu 18.04.

When you have an account available, log in as your non-root user to begin.


Installing Nginx
Because Nginx is available in Ubuntu's default repositories, it is possible to install it from these repositories using the apt packaging system.

Since this is our first interaction with the apt packaging system in this session, we will update our local package index so that we have access to the most recent package listings. Afterwards, we can install nginx:

sudo apt update
sudo apt install nginx

After accepting the procedure, apt will install Nginx and any required dependencies to your server.


Adjusting the Firewall
Before testing Nginx, the firewall software needs to be adjusted to allow access to the service. Nginx registers itself as a service with ufw upon installation, making it straightforward to allow Nginx access.

List the application configurations that ufw knows how to work with by typing:

sudo ufw app list

You should get a listing of the application profiles:

Output
Available applications:
  Nginx Full
  Nginx HTTP
  Nginx HTTPS
  OpenSSH

As you can see, there are three profiles available for Nginx:

Nginx Full: This profile opens both port 80 (normal, unencrypted web traffic) and port 443 (TLS/SSL encrypted traffic)
Nginx HTTP: This profile opens only port 80 (normal, unencrypted web traffic)
Nginx HTTPS: This profile opens only port 443 (TLS/SSL encrypted traffic)

It is recommended that you enable the most restrictive profile that will still allow the traffic you've configured. Since we haven't configured SSL for our server yet in this guide, we will only need to allow traffic on port 80.

You can enable this by typing:

sudo ufw allow 'Nginx HTTP'

You can verify the change by typing:

sudo ufw status

You should see HTTP traffic allowed in the displayed output:

Output
Status: active

To                         Action      From
--                         ------      ----
OpenSSH                    ALLOW       Anywhere                 
Nginx HTTP                 ALLOW       Anywhere                 
OpenSSH (v6)               ALLOW       Anywhere (v6)            
Nginx HTTP (v6)            ALLOW       Anywhere (v6)


Checking your Web Server
At the end of the installation process, Ubuntu 18.04 starts Nginx. The web server should already be up and running.

We can check with the systemd init system to make sure the service is running by typing:

systemctl status nginx

Output
nginx.service - A high performance web server and a reverse proxy server
   Loaded: loaded (/lib/systemd/system/nginx.service; enabled; vendor preset: enabled)
   Active: active (running) since Fri 2018-04-20 16:08:19 UTC; 3 days ago
     Docs: man:nginx(8)
 Main PID: 2369 (nginx)
    Tasks: 2 (limit: 1153)
   CGroup: /system.slice/nginx.service
           ├─2369 nginx: master process /usr/sbin/nginx -g daemon on; master_process on;
           └─2380 nginx: worker process

As you can see above, the service appears to have started successfully. However, the best way to test this is to actually request a page from Nginx.

You can access the default Nginx landing page to confirm that the software is running properly by navigating to your server's IP address. If you do not know your server's IP address, you can get it a few different ways.

Try typing this at your server's command prompt:

ip addr show eth0 | grep inet | awk '{ print $2; }' | sed 's/\/.*$//'

You will get back a few lines. You can try each in your web browser to see if they work.

An alternative is typing this, which should give you your public IP address as seen from another location on the internet:

curl -4 icanhazip.com

When you have your server's IP address, enter it into your browser's address bar:

http://your_server_ip

You should see the default Nginx landing page:



This page is included with Nginx to show you that the server is running correctly.


Managing the Nginx Process
Now that you have your web server up and running, let's review some basic management commands.

To stop your web server, type:

sudo systemctl stop nginx

To start the web server when it is stopped, type:

sudo systemctl start nginx

To stop and then start the service again, type:

sudo systemctl restart nginx

If you are simply making configuration changes, Nginx can often reload without dropping connections. To do this, type:

sudo systemctl reload nginx

By default, Nginx is configured to start automatically when the server boots. If this is not what you want, you can disable this behavior by typing:

sudo systemctl disable nginx

To re-enable the service to start up at boot, you can type:

sudo systemctl enable nginx


Setting Up Server Blocks (Recommended)
When using the Nginx web server, server blocks (similar to virtual hosts in Apache) can be used to encapsulate configuration details and host more than one domain from a single server. We will set up a domain called example.com, but you should replace this with your own domain name.

Nginx on Ubuntu 18.04 has one server block enabled by default that is configured to serve documents out of a directory at /var/www/html. While this works well for a single site, it can become unwieldy if you are hosting multiple sites. Instead of modifying /var/www/html, let's create a directory structure within /var/www for our example.com site, leaving /var/www/html in place as the default directory to be served if a client request doesn't match any other sites.

Create the directory for example.com as follows, using the -p flag to create any necessary parent directories:

sudo mkdir -p /var/www/example.com/html

Next, assign ownership of the directory with the $USER environment variable:

sudo chown -R $USER:$USER /var/www/example.com/html

The permissions of your web roots should be correct if you haven't modified your umask value, but you can make sure by typing:

sudo chmod -R 755 /var/www/example.com

Next, create a sample index.html page using nano or your favorite editor:

nano /var/www/example.com/html/index.html

Inside, add the following sample HTML:

<html>
    <head>
        <title>Welcome to Example.com!</title>
    </head>
    <body>
        <h1>Success!  The example.com server block is working!</h1>
    </body>
</html>

Save and close the file when you are finished.

In order for Nginx to serve this content, it's necessary to create a server block with the correct directives. Instead of modifying the default configuration file directly, let’s make a new one at /etc/nginx/sites-available/example.com:

sudo nano /etc/nginx/sites-available/example.com

Paste in the following configuration block, which is similar to the default, but updated for our new directory and domain name:

server {
        listen 80;
        listen [::]:80;

        root /var/www/example.com/html;
        index index.html index.htm index.nginx-debian.html;

        server_name example.com www.example.com;

        location / {
                try_files $uri $uri/ =404;
        }
}

Notice that we’ve updated the root configuration to our new directory, and the server_name to our domain name.

Next, let's enable the file by creating a link from it to the sites-enabled directory, which Nginx reads from during startup:

sudo ln -s /etc/nginx/sites-available/example.com /etc/nginx/sites-enabled/

Two server blocks are now enabled and configured to respond to requests based on their listen and server_name directives

example.com: Will respond to requests for example.com and www.example.com.
default: Will respond to any requests on port 80 that do not match the other two blocks.

To avoid a possible hash bucket memory problem that can arise from adding additional server names, it is necessary to adjust a single value in the /etc/nginx/nginx.conf file. Open the file:

sudo nano /etc/nginx/nginx.conf

Find the server_names_hash_bucket_size directive and remove the # symbol to uncomment the line:

http {

    server_names_hash_bucket_size 64;
}

Next, test to make sure that there are no syntax errors in any of your Nginx files:

sudo nginx -t

Save and close the file when you are finished.

If there aren't any problems, restart Nginx to enable your changes:

sudo systemctl restart nginx

Nginx should now be serving your domain name. You can test this by navigating to http://example.com, where you should see something like this:



Wrapping up
Now that you have your web server installed, you have many options for the type of content to serve and the technologies you want to use to create a richer experience.

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