How to Configure Apache Reverse Proxy on CentOS

Description: Here I have explained what is Apache Reverse Proxy and How to configure it.

What is Reverse Proxy: 
A reverse proxy accepts connections and then routes them to an appropriate path.

For example, if we have any application running on port 5000, we can configure a reverse proxy to accept connections on HTTP or HTTPS, which can then transparently proxy requests to the application backend.

Configure Reverse Proxy.

1. Verify Proxy module using below command

# httpd -M

Output

proxy_module (shared)

lbmethod_byrequests_module (shared)

proxy_balancer_module (shared)

proxy_http_module (shared

      2. Configure Virtual Host as follow: [We’ll use example application running on 127.0.0.1:5000 as the backend service that we want to reverse proxy requests to]

 


<VirtualHost *:443>

        # The ServerName directive sets the request scheme, hostname and port that

        # the server uses to identify itself. This is used when creating

        # redirection URLs. In the context of virtual hosts, the ServerName

        # specifies what hostname must appear in the request's Host: header to

        # match this virtual host. For the default virtual host (this file) this

        # value is not decisive as it is used as a last resort host regardless.

        # However, you must set it for any further virtual host explicitly.

        #ServerName www.example.com

        ProxyPreserveHost On

        ProxyPass /api http://127.0.0.1:5000

        ProxyPassReverse /api http://127.0.0.1:5000

         ServerAdmin webmaster@localhost

        ServerName app1.demo.com

        ServerAlias app1.demo.com

        DocumentRoot /var/www/html/demoapp

SSLEngine on

SSLCertificateFile /var/www/html/certs/demo.crt

SSLCertificateKeyFile /var/www/html/certs/demo.key

SSLCertificateChainFile /var/www/html/certs/demo_CA.crt



        # Available loglevels: trace8, ..., trace1, debug, info, notice, warn,

        # error, crit, alert, emerg.

        # It is also possible to configure the loglevel for particular

        # modules, e.g.

        #LogLevel info ssl:warn



        ErrorLog ${APACHE_LOG_DIR}/error.log

        CustomLog ${APACHE_LOG_DIR}/access.log combined



        # For most configuration files from conf-available/, which are

        # enabled or disabled at a global level, it is possible to

        # include a line for only one particular virtual host. For example the

        # following line enables the CGI configuration for this host only

        # after it has been globally disabled with "a2disconf".

        #Include conf-available/serve-cgi-bin.conf

</VirtualHost>

• Restart httpd service and verify. 

# systemctl start httpd