Chapter 2. Setting up and configuring NGINX

Procedure

1. Display the available NGINX module streams:

   # yum module list nginx
   Red Hat Enterprise Linux 8 for x86_64 - AppStream (RPMs)
   Name        Stream        Profiles        Summary
   nginx       1.14 [d]      common [d]      nginx webserver
   nginx       1.16          common [d]      nginx webserver
   ...
   
   Hint: [d]efault, [e]nabled, [x]disabled, [i]nstalled

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2. If you want to install a different stream than the default, select the stream:

   # yum module enable nginx:stream_version

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3. Install the nginx package:

   # yum install nginx

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4. Open the ports on which NGINX should provide its service in the firewall. For example, to open the default ports for HTTP (port 80) and HTTPS (port 443) in firewalld, enter:

   # firewall-cmd --permanent --add-port={80/tcp,443/tcp}
   # firewall-cmd --reload

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5. Enable the nginx service to start automatically when the system boots:

   # systemctl enable nginx

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6. Optional: Start the nginx service:

   # systemctl start nginx

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   If you do not want to use the default configuration, skip this step, and configure NGINX accordingly before you start the service.

Verification

1. Use the yum utility to verify that the nginx package is installed:

   # yum list installed nginx
   Installed Packages
   nginx.x86_64    1:1.14.1-9.module+el8.0.0+4108+af250afe    @rhel-8-for-x86_64-appstream-rpms

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2. Ensure that the ports on which NGINX should provide its service are opened in the firewalld:

   # firewall-cmd --list-ports
   80/tcp 443/tcp

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3. Verify that the nginx service is enabled:

   # systemctl is-enabled nginx
   enabled

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Procedure

1. Edit the /etc/nginx/nginx.conf file:

   1. By default, the /etc/nginx/nginx.conf file already contains a catch-all configuration. If you have deleted this part from the configuration, re-add the following server block to the http block in the /etc/nginx/nginx.conf file:

      server {
          listen       80 default_server;
          listen       [::]:80 default_server;
          server_name  _;
          root         /usr/share/nginx/html;
      }

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      These settings configure the following:

      • The listen directive define which IP address and ports the service listens. In this case, NGINX listens on port 80 on both all IPv4 and IPv6 addresses. The default_server parameter indicates that NGINX uses this server block as the default for requests matching the IP addresses and ports.
      • The server_name parameter defines the host names for which this server block is responsible. Setting server_name to _ configures NGINX to accept any host name for this server block.
      • The root directive sets the path to the web content for this server block.

   2. Append a similar server block for the example.com domain to the http block:

      server {
          server_name  example.com;
          root         /var/www/example.com/;
          access_log   /var/log/nginx/example.com/access.log;
          error_log    /var/log/nginx/example.com/error.log;
      }

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      • The access_log directive defines a separate access log file for this domain.
      • The error_log directive defines a separate error log file for this domain.

   3. Append a similar server block for the example.net domain to the http block:

      server {
          server_name  example.net;
          root         /var/www/example.net/;
          access_log   /var/log/nginx/example.net/access.log;
          error_log    /var/log/nginx/example.net/error.log;
      }

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2. Create the root directories for both domains:

   # mkdir -p /var/www/example.com/
   # mkdir -p /var/www/example.net/

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3. Set the httpd_sys_content_t context on both root directories:

   # semanage fcontext -a -t httpd_sys_content_t "/var/www/example.com(/.*)?"
   # restorecon -Rv /var/www/example.com/
   # semanage fcontext -a -t httpd_sys_content_t "/var/www/example.net(/.\*)?"
   # restorecon -Rv /var/www/example.net/

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   These commands set the httpd_sys_content_t context on the /var/www/example.com/ and /var/www/example.net/ directories.

   Note that you must install the policycoreutils-python-utils package to run the restorecon commands.

4. Create the log directories for both domains:

   # mkdir /var/log/nginx/example.com/
   # mkdir /var/log/nginx/example.net/

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5. Restart the nginx service:

   # systemctl restart nginx

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Verification

1. Create a different example file in each virtual host’s document root:

   # echo "Content for example.com" > /var/www/example.com/index.html
   # echo "Content for example.net" > /var/www/example.net/index.html
   # echo "Catch All content" > /usr/share/nginx/html/index.html

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2. Use a browser and connect to http://example.com. The web server shows the example content from the /var/www/example.com/index.html file.
3. Use a browser and connect to http://example.net. The web server shows the example content from the /var/www/example.net/index.html file.
4. Use a browser and connect to http://IP_address_of_the_server. The web server shows the example content from the /usr/share/nginx/html/index.html file.

Procedure

1. Edit the /etc/nginx/nginx.conf file, and add the following server block to the http block in the configuration:

   server {
       listen              443 ssl;
       server_name         example.com;
       root                /usr/share/nginx/html;
       ssl_certificate     /etc/pki/tls/certs/example.com.crt;
       ssl_certificate_key /etc/pki/tls/private/example.com.key;
   }

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2. For security reasons, configure that only the root user can access the private key file:

   # chown root:root /etc/pki/tls/private/example.com.key
   # chmod 600 /etc/pki/tls/private/example.com.key

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   Warning

   If the private key was accessed by unauthorized users, revoke the certificate, create a new private key, and request a new certificate. Otherwise, the TLS connection is no longer secure.

3. Restart the nginx service:

   # systemctl restart nginx

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Procedure

1. Edit the /etc/nginx/nginx.conf file and add the following settings to the server block that should provide the reverse proxy:

   location /example {
       proxy_pass https://example.com;
   }

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   The location block defines that NGINX passes all requests in the /example directory to https://example.com.

2. Set the httpd_can_network_connect SELinux boolean parameter to 1 to configure that SELinux allows NGINX to forward traffic:

   # setsebool -P httpd_can_network_connect 1

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3. Restart the nginx service:

   # systemctl restart nginx

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Procedure

1. Edit the /etc/nginx/nginx.conf file and add the following settings:

   http {
       upstream backend {
           least_conn;
           server server1.example.com;
           server server2.example.com;
           server server3.example.com backup;
       }
   
       server {
           location / {
               proxy_pass http://backend;
           }
       }
   }

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   The least_conn directive in the host group named backend defines that NGINX sends requests to server1.example.com or server2.example.com, depending on which host has the least number of active connections. NGINX uses server3.example.com only as a backup in case that the other two hosts are not available.

   With the proxy_pass directive set to http://backend, NGINX acts as a reverse proxy and uses the backend host group to distribute requests based on the settings of this group.

   Instead of the least_conn load balancing method, you can specify:

   • No method to use round robin and distribute requests evenly across servers.
   • ip_hash to send requests from one client address to the same server based on a hash calculated from the first three octets of the IPv4 address or the whole IPv6 address of the client.
   • hash to determine the server based on a user-defined key, which can be a string, a variable, or a combination of both. The consistent parameter configures that NGINX distributes requests across all servers based on the user-defined hashed key value.
   • random to send requests to a randomly selected server.

2. Restart the nginx service:

   # systemctl restart nginx

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