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How To Configure Nginx as a Web Server and Reverse Proxy for Apache on One Ubuntu 16.04 Server

PostedJuly 6, 2016 78.8k views Nginx Apache PHP Ubuntu 16.04

Introduction

Apache and Nginx are two popular open source web servers often used with PHP. It can be useful to run both of them on the same virtual machine when hosting multiple websites which have varied requirements. The general solution for running two web servers on a single system is to either use multiple IP addresses or different port numbers.

Droplets which have both IPv4 and IPv6 addresses can be configured to serve Apache sites on one protocol and Nginx sites on the other, but this isn't currently practical, as IPv6 adoption by ISPs is still not widespread. Having a different port number like 81 or 8080 for the second web server is another solution, but sharing URLs with port numbers (such as http://example.com:81) isn't always reasonable or ideal.

This tutorial will show you how to configure Nginx as both a web server and as a reverse proxy for Apache – all on one Droplet. Depending on the web application, code changes might be required to keep Apache reverse-proxy-aware, especially when SSL sites are configured. To avoid this, we will install an Apache module named mod_rpaf which rewrites certain environment variables so it appears that Apache is directly handling requests from web clients.

We will host four domain names on one Droplet. Two will be served by Nginx: example.com (the default virtual host) and sample.org. The remaining two, foobar.net and test.io, will be served by Apache.

Prerequisites

  • A new Ubuntu 16.04 Droplet.
  • A standard user account with sudo privileges. You can set up a standard account by following Steps 2 and 3 of the Initial Server Setup with Ubuntu 16.04.
  • The desired domain names should point to your Droplet's IP address in the DigitalOcean control panel. See Step 3 of How To Set Up a Host Name with DigitalOcean for an example of how to do this. If you host your domains' DNS elsewhere, you should create appropriate A records there instead.

Optional References

This tutorial requires basic knowledge of virtual hosts in Apache and Nginx, as well as SSL certificate creation and configuration. For more information on these topics, see the following articles.

Step 1 — Installing Apache and PHP-FPM

In addition to Apache and PHP-FPM, we must also install the PHP FastCGI Apache module which is named libapache2-mod-fastcgi.

First, update the apt repository to ensure you have the latest packages.

  • sudo apt-get update

Next, install the necessary packages:

  • sudo apt-get install apache2 libapache2-mod-fastcgi php-fpm

Next, let's change Apache's default configuration.

Step 2 — Configuring Apache and PHP-FPM

In this step we will change Apache's port number to 8080 and configure it to work with PHP-FPM using the mod_fastcgi module. Edit the Apache configuration file and change the port number of Apache.

  • sudo nano /etc/apache2/ports.conf

Find the following line:

Listen 80

Change it to:

Listen 8080

Save and exit ports.conf.

Note: Web servers are generally set to listen on 127.0.0.1:8080 when configuring a reverse proxy but doing so would set the value of PHP's environment variable SERVER_ADDR to the loopback IP address instead of the server's public IP. Our aim is to set up Apache in such a way that its websites do not see a reverse proxy in front of it. So, we will configure it to listen on 8080 on all IP addresses.

Next we'll edit the default virtual host file of Apache. The <VirtualHost> directive in this file is set to serve sites only on port 80, so we'll have to change that as well. Open the default virtual host file.

  • sudo nano /etc/apache2/sites-available/000-default.conf

The first line should be:

<VirtualHost *:80>

Change it to:

<VirtualHost *:8080>

Save the file and reload Apache.

  • sudo systemctl reload apache2

Verify that Apache is now listening on 8080.

  • sudo netstat -tlpn

The output should look like the following example, with apache2 listening on :::8080.

Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address     Foreign Address      State    PID/Program name
tcp        0      0 0.0.0.0:22        0.0.0.0:*            LISTEN   1086/sshd
tcp6       0      0 :::8080           :::*                 LISTEN   4678/apache2
tcp6       0      0 :::22             :::*                 LISTEN   1086/sshd

Once you verify that Apache is listening on the correct port, you can configure support for PHP and FastCGI.

Step 3 — Configuring Apache to Use mod_fastcgi

Apache serves PHP pages using mod_php by default, but it requires additional configuration to work with PHP-FPM.

Note: If you are trying this tutorial on an existing installation of LAMP with mod_php, disable it first with:

  • sudo a2dismod php7.0

We will be adding a configuration block for mod_fastcgi which depends on mod_action. mod_action is disabled by default, so we first need to enable it.

  • sudo a2enmod actions

These configuration directives pass requests for .php files to the PHP-FPM UNIX socket.

  • sudo nano /etc/apache2/mods-enabled/fastcgi.conf

Add the following lines within the <IfModule mod_fastcgi.c> . . . </IfModule> block, below the existing items in that block:

 AddType application/x-httpd-fastphp .php
 Action application/x-httpd-fastphp /php-fcgi
 Alias /php-fcgi /usr/lib/cgi-bin/php-fcgi
 FastCgiExternalServer /usr/lib/cgi-bin/php-fcgi -socket /run/php/php7.0-fpm.sock -pass-header Authorization
 <Directory /usr/lib/cgi-bin>
    Require all granted
 </Directory>

Save the changes you made to fastcgi.conf and do a configuration test.

  • sudo apachectl -t

Reload Apache if Syntax OK is displayed. If you see the warning Could not reliably determine the server's fully qualified domain name, using 127.0.1.1. Set the 'ServerName' directive globally to suppress this message., that's fine. It doesn't affect us now.

  • sudo systemctl reload apache2

Now let's make sure we can serve PHP from Apache.

Step 4 — Verifying PHP Functionality

Check if PHP works by creating a phpinfo() file and accessing it from your web browser.

  • echo "<?php phpinfo(); ?>" | sudo tee /var/www/html/info.php

To see the file in a browser, go to http://your_ip_address:8080/info.php. This will give you a list of configuration settings PHP is using.

phpinfo Server API

phpinfo PHP Variables

At the top of the page, check that Server API says FPM/FastCGI. About two-thirds of the way down the page, the PHP Variables section will tell you the SERVER_SOFTWARE is Apache on Ubuntu. These confirm that mod_fastcgi is active and Apache is using PHP-FPM to process PHP files.

Step 5 — Creating Virtual Hosts for Apache

Let's create Apache virtual host files for the domains foobar.net and test.io. To do that, we'll first create document root directories for both sites and place some default files in those directories so we can easily test our configuration.

First, create the root directories:

  • sudo mkdir -v /var/www/{foobar.net,test.io}

Then create an index file for each site.

  • echo "<h1 style='color: green;'>Foo Bar</h1>" | sudo tee /var/www/foobar.net/index.html
  • echo "<h1 style='color: red;'>Test IO</h1>" | sudo tee /var/www/test.io/index.html

Then create a phpinfo() file for each site so we can test PHP is configured properly.

  • echo "<?php phpinfo(); ?>" | sudo tee /var/www/foobar.net/info.php
  • echo "<?php phpinfo(); ?>" | sudo tee /var/www/test.io/info.php

Now create the virtual host file for the foobar.net domain.

  • sudo nano /etc/apache2/sites-available/foobar.net.conf

Place the following directive in this new file:

<VirtualHost *:8080>
    ServerName foobar.net
    ServerAlias www.foobar.net
    DocumentRoot /var/www/foobar.net
    <Directory /var/www/foobar.net>
        AllowOverride All
    </Directory>
</VirtualHost>

Note: AllowOverride All enables .htaccess support.

These are only the most basic directives. For a complete guide on setting up virtual hosts in Apache, see How To Set Up Apache Virtual Hosts on Ubuntu 16.04.

Save and close the file. Then create a similar configuration for test.io.

  • sudo nano /etc/apache2/sites-available/test.io.conf
<VirtualHost *:8080>
    ServerName test.io
    ServerAlias www.test.io
    DocumentRoot /var/www/test.io
    <Directory /var/www/test.io>
        AllowOverride All
    </Directory>
</VirtualHost>

Now that both Apache virtual hosts are set up, enable the sites using the a2ensite command. This creates a symbolic link to the virtual host file in the sites-enabled directory.

  • sudo a2ensite foobar.net
  • sudo a2ensite test.io

Check Apache for configuration errors again.

  • sudo apachectl -t

Reload Apache if Syntax OK is displayed.

  • sudo systemctl reload apache2

To confirm the sites are working, open http://foobar.net:8080 and http://test.io:8080 in your browser and verify that each site displays its index.html file.

You should see the following results:

foobar.net index page

test.io index page

Also, check that PHP is working by accessing the info.php files for each site. Visit http://foobar.net:8080/info.php and http://test.io:8080/info.php in your browser.

You should see the same PHP configuration spec list on each site as you saw in Step 4. We now have two websites hosted on Apache at port 8080

Step 6 — Installing and Configuring Nginx

In this step we'll install Nginx and configure the domains example.com and sample.org as Nginx's virtual hosts. For a complete guide on setting up virtual hosts in Nginx, see How To Set Up Nginx Server Blocks (Virtual Hosts) on Ubuntu 16.04.

Install Nginx using the package manager.

  • sudo apt-get install nginx

Then remove the default virtual host's symlink since we won't be using it any more. We'll create our own default site later (example.com).

  • sudo rm /etc/nginx/sites-enabled/default

Now we'll create virtual hosts for Nginx using the same procedure we used for Apache. First create document root directories for both the websites:

  • sudo mkdir -v /usr/share/nginx/{example.com,sample.org}

As we did with Apache's virtual hosts, we'll again create index and phpinfo() files for testing after setup is complete.

  • echo "<h1 style='color: green;'>Example.com</h1>" | sudo tee /usr/share/nginx/example.com/index.html
  • echo "<h1 style='color: red;'>Sample.org</h1>" | sudo tee /usr/share/nginx/sample.org/index.html
  • echo "<?php phpinfo(); ?>" | sudo tee /usr/share/nginx/example.com/info.php
  • echo "<?php phpinfo(); ?>" | sudo tee /usr/share/nginx/sample.org/info.php

Now create a virtual host file for the domain example.com.

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

Nginx calls server {. . .} areas of a configuration file server blocks. Create a server block for the primary virtual host, example.com. The default_server configuration directive makes this the default virtual host which processes HTTP requests that do not match any other virtual host.

Paste the following into the file for example.com:

server {
    listen 80 default_server;

    root /usr/share/nginx/example.com;
    index index.php index.html index.htm;

    server_name example.com www.example.com;
    location / {
        try_files $uri $uri/ /index.php;
    }

    location ~ \.php$ {
        fastcgi_pass unix:/run/php/php7.0-fpm.sock;
        include snippets/fastcgi-php.conf;
    }
}

Save and close the file. Now create a virtual host file for Nginx's second domain, sample.org.

  • sudo nano /etc/nginx/sites-available/sample.org

The server block for sample.org should look like this:

server {
    root /usr/share/nginx/sample.org;
    index index.php index.html index.htm;

    server_name sample.org www.sample.org;
    location / {
        try_files $uri $uri/ /index.php;
    }

    location ~ \.php$ {
        fastcgi_pass unix:/run/php/php7.0-fpm.sock;
        include snippets/fastcgi-php.conf;
    }
}

Save and close the file. Then enable both the sites by creating symbolic links to the sites-enabled directory.

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

Do an Nginx configuration test:

  • sudo nginx -t

Then reload Nginx if OK is displayed.

  • sudo systemctl reload nginx

Now acccess the phpinfo() file of your Nginx virtual hosts in a web browser by visiting http://example.com/info.php and http://sample.org/info.php. Look under the PHP Variables sections again.

Nginx PHP Variables

["SERVER_SOFTWARE"] should say nginx, indicating that the files were directly served by Nginx. ["DOCUMENT_ROOT"] should point to the directory you created earlier in this step for each Nginx site.

At this point, we have installed Nginx and created two virtual hosts. Next we will configure Nginx to proxy requests meant for domains hosted on Apache.

Step 7 — Configuring Nginx for Apache's Virtual Hosts

Let's create an additional Nginx virtual host with multiple domain names in the server_name directives. Requests for these domain names will be proxied to Apache.

Create a new Nginx virtual host file:

  • sudo nano /etc/nginx/sites-available/apache

Add the code block below. This specifies the names of both Apache virtual host domains, and proxies their requests to Apache. Remember to use the public IP address in proxy_pass.

server {
    listen 80;
    server_name foobar.net www.foobar.net test.io www.test.io;

    location / {
        proxy_pass http://your_server_ip:8080;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }
}

Save the file and enable this new virtual host by creating a symbolic link.

  • sudo ln -s /etc/nginx/sites-available/apache /etc/nginx/sites-enabled/apache

Do a configuration test:

  • sudo nginx -t

Reload Nginx if OK is displayed.

  • sudo systemctl reload nginx

Open the browser and access the URL http://foobar.net/info.php in your browser. Scroll down to the PHP Variables section and check the values displayed.

phpinfo of Apache via Nginx

The variables SERVER_SOFTWARE and DOCUMENT_ROOT confirm that this request was handled by Apache. The variables HTTPXREAL_IP and HTTPXFORWARDED_FOR were added by Nginx and should show the public IP address of the computer you're using to access the URL.

We have successfully set up Nginx to proxy requests for specific domains to Apache. Next, let's configure Apache to set the REMOTE_ADDR variable as if it were handling these requests directly.

Step 8 — Installing and Configuring mod_rpaf

In this step we will install an Apache module named mod_rpaf which rewrites the values of REMOTE_ADDR, HTTPS and HTTP_PORT based on the values provided by a reverse proxy. Without this module, some PHP applications would require code changes to work seamlessly from behind a proxy. This module is present in Ubuntu's repository as libapache2-mod-rpaf but is outdated and doesn't support certain configuration directives. Instead, we will install it from source.

Install the packages needed to build the module:

  • sudo apt-get install unzip build-essential apache2-dev

Download the latest stable release from GitHub.

  • wget https://github.com/gnif/mod_rpaf/archive/stable.zip

Extract it with:

  • unzip stable.zip

Change into the working directory.

  • cd mod_rpaf-stable

Then compile and install the module.

  • make
  • sudo make install

Create a file in the mods-available directory which loads the rpaf module.

  • sudo nano /etc/apache2/mods-available/rpaf.load

Add the following line to the file:

LoadModule rpaf_module /usr/lib/apache2/modules/mod_rpaf.so

Create another file in this directory. This will contain the configuration directives.

  • sudo nano /etc/apache2/mods-available/rpaf.conf

Add the following code block, making sure to add the IP address of your Droplet.

<IfModule mod_rpaf.c>
    RPAF_Enable             On
    RPAF_Header             X-Real-Ip
    RPAF_ProxyIPs           your_server_ip 
    RPAF_SetHostName        On
    RPAF_SetHTTPS           On
    RPAF_SetPort            On
</IfModule>

Here's a brief description of each directive. See the mod_rpaf README file for more information.

  • RPAF_Header - The header to use for the client's real IP address.
  • RPAF_ProxyIPs - The proxy IP to adjust HTTP requests for.
  • RPAF_SetHostName - Updates the vhost name so ServerName and ServerAlias work.
  • RPAF_SetHTTPS - Sets the HTTPS environment variable based on the value contained in X-Forwarded-Proto.
  • RPAF_SetPort - Sets the SERVER_PORT environment variable. Useful for when Apache is behind a SSL proxy.

Save rpaf.conf and enable the module.

  • sudo a2enmod rpaf

This creates symbolic links of the files rpaf.load and rpaf.conf in the mods-enabled directory. Now do a configuration test.

  • sudo apachectl -t

Reload Apache if Syntax OK is returned.

  • sudo systemctl reload apache2

Access one of Apache's websites' phpinfo() pages in your browser and check the PHP Variables section. The REMOTE_ADDR variable will now also be that of your local computer's public IP address.

Step 9 — Setting Up HTTPS Websites (Optional)

In this step we will configure SSL certificates for both the domains hosted on Apache. Nginx supports SSL termination so we can set up SSL without modifying Apache's configuration files. The mod_rpaf module ensures the required environment variables are set on Apache to make applications work seamlessly behind a SSL reverse proxy.

Create a directory for the SSL certificates and their private keys.

  • sudo mkdir /etc/nginx/ssl

For this article we will use self-signed SSL certificates with a validity of 10 years. Generate self-signed certificates for both foobar.net and test.io.

  • sudo openssl req -x509 -sha256 -newkey rsa:2048 -keyout /etc/nginx/ssl/foobar.net-key.pem -out /etc/nginx/ssl/foobar.net-cert.pem -days 3650 -nodes
  • sudo openssl req -x509 -sha256 -newkey rsa:2048 -keyout /etc/nginx/ssl/test.io-key.pem -out /etc/nginx/ssl/test.io-cert.pem -days 3650 -nodes

Each time, you will be prompted for certificate identification details. Enter the appropriate domain for the Common Name each time.

Country Name (2 letter code) [AU]:US
State or Province Name (full name) [Some-State]:New York
Locality Name (eg, city) []:New York City
Organization Name (eg, company) [Internet Widgits Pty Ltd]:DigitalOcean Inc
Organizational Unit Name (eg, section) []:
Common Name (e.g. server FQDN or YOUR name) []:foobar.net
Email Address []:

Now open the Apache virtual host file that proxies requests from Nginx to Apache.

  • sudo nano /etc/nginx/sites-available/apache

Since we have separate certificates and keys for each domain, we need to have separate server { . . . } blocks for each domain. You should delete the file's current contents and replace it with the following contents:

server {
    listen 80;
    listen 443 ssl;
    server_name test.io www.test.io;

    ssl on;
    ssl_certificate /etc/nginx/ssl/test.io-cert.pem;
    ssl_certificate_key /etc/nginx/ssl/test.io-key.pem;

    location / {
        proxy_pass http://your_server_ip:8080;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }
}

server {
    listen 80;
    listen 443 ssl;
    server_name foobar.net www.foobar.net;

    ssl on;
    ssl_certificate /etc/nginx/ssl/foobar.net-cert.pem;
    ssl_certificate_key /etc/nginx/ssl/foobar.net-key.pem;

    location / {
        proxy_pass http://your_server_ip:8080;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }
}

We split apart the original server block into two separate blocks, and we also told Nginx to listen on Port 443, the default port for secure sites.

Save the file and perform a configuration test.

  • sudo nginx -t

Reload Nginx if the test succeeds.

  • sudo systemctl reload nginx

Now, access one of Apache's domains in your browser using the https:// prefix. First, visit https://foobar.net/info.php and you'll see this:

phpinfo ssl

We used a self-signed certificate for this tutorial, and so the browser may warn us that the connection might not be trusted. You can safely proceed by trusting the site.

Look in the PHP Variables section. The variable SERVER_PORT has been set to 443 and HTTPS set to on, as though Apache was directly accessed over HTTPS. With these variables set, PHP applications do not have to be specially configured to work behind a reverse proxy.

Step 10 — Blocking Direct Access to Apache (Optional)

Since Apache is listening on port 8080 on the public IP address, it is accessible by everyone. It can be blocked by working the following IPtables command into your firewall rule set.

  • sudo iptables -I INPUT -p tcp --dport 8080 ! -s your_server_ip -j REJECT --reject-with tcp-reset

Be sure to use your Droplet's IP address in place of the example in red. Once port 8080 is blocked in your firewall, test that Apache is unreachable on it. Open your web browser and try accessing one of Apache's domain names on port 8080. For example: http://example.com:8080

The browser should display an "Unable to connect" or "Webpage is not available" error message. With the IPtables tcp-reset option in place, an outsider would see no difference between port 8080 and a port that doesn't have any service on it.

Note: IPtables rules do not survive a system reboot by default. There are multiple ways to preserve IPtables rules, but the easiest is to use iptables-persistent in Ubuntu's repository. Explore this article to learn more about how to configure IPTables.

Step 11 — Serving Static Files Using Nginx (Optional)

When Nginx proxies requests for Apache's domains, it sends every file request for that domain to Apache. Nginx is faster than Apache in serving static files like images, JavaScript and style sheets. So let's configure Nginx's apache virtual host file to directly serve static files but send PHP requests on to Apache.

First, open the apache virtual host file.

  • sudo nano /etc/nginx/sites-available/apache

You'll need to add two additional location blocks to each server block, and modify the existing location blocks. (If you have just one server block from the earlier step, you can completely replace the contents of your file so it matches the content shown below.) In addition, you'll need to tell Nginx where to find the static files for each site. These changes are shown in red in the following code:

server {
    listen 80;
    server_name test.io www.test.io;
    root /var/www/test.io;
    index index.php index.htm index.html;

    location / {
        try_files $uri $uri/ /index.php;
    }

    location ~ \.php$ {
        proxy_pass http://your_ip_address:8080;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }

    location ~ /\. {
        deny all;
    }
}

server {
    listen 80;
    server_name foobar.net www.foobar.net;
    root /var/www/foobar.net;
    index index.php index.htm index.html;

    location / {
        try_files $uri $uri/ /index.php;
    }

    location ~ \.php$ {
        proxy_pass http://your_ip_address:8080;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }

    location ~ /\. {
        deny all;
    }
}

If you also want HTTPS to be available, preserve the listen 443 ssl; line and the other SSL settings from Step 9.

The try_files directive makes Nginx look for files in the document root and directly serve them. If the file has a .php extension, the request is passed to Apache. Even if the file is not found in the document root, the request is passed on to Apache so that application features like permalinks work without problems.

Warning: The location ~ /\. directive is very important; this prevents Nginx from printing the contents of files like .htaccess and .htpasswd which contain sensitive information.

Save the file and perform a configuration test.

  • sudo nginx -t

Reload Nginx if the test succeeds.

  • sudo service nginx reload

To verify this is working, you can examine Apache's log files in /var/log/apache2 and see the GET requests for the info.php files of test.io and foobar.net. Use the tail command to see the last few lines of the file, and use the -f switch to watch the file for changes.

  • sudo tail -f /var/log/apache2/other_vhosts_access.log

Visit http://test.io/info.php in your browser and then look at the output from the log. You'll see that Apache is indeed replying:

 test.io:80 your_server_ip - - [01/Jul/2016:18:18:34 -0400] "GET /info.php HTTP/1.0" 200 20414 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/47.0.2526.111 Safari/537.36"

Then visit the index.html page for each site and you won't see any log entries from Apache. Nginx is serving them.

When you're done observing the log file, press CTRL+C to stop tailing it.

The only caveat for this setup is that Apache will not be able to restrict access to static files. Access control for static files would need to be configured in Nginx's apache virtual host file.

Conclusion

You now have one Ubuntu Droplet with Nginx serving example.com and sample.org, along with Apache serving foobar.net and test.io. Though Nginx is acting as a reverse-proxy for Apache, Nginx's proxy service is transparent and connections to Apache's domains appear be served directly from Apache itself. You can use this method to serve secure and static sites.

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