Complex websites are often handled by multiple web servers, all containing the same code. Sometimes it can be necessary to split a website into multiple applications, all served from the same domain. The primary way of handling multiple, separate websites served under a single domain is to use a proxy server. A proxy server is usually another server that handles requests from resources on servers by clients.

For more information on the different proxies available on Cloud Platform, see Proxies and Acquia Cloud.

You can implement a mod_proxy configuration by using Apache's mod_proxy module on Cloud Platform. You can manage mod_proxy on each environment by using the self-service configuration settings in the Cloud Platform user interface. However, you cannot implement a custom mod_proxy configuration.

With this feature, you can:

• Enable or disable mod_proxy through the Cloud Platform user interface.
• Configure mod_proxy on each environment.

Considerations before enabling mod_proxy¶

Before you enable mod_proxy:

• Understand that using mod_proxy introduces a dependency on downstream systems that are external to Acquia. Such systems are outside the scope of Acquia's support or advice.
• Know that dependency on any external service can negatively impact your Acquia-hosted sites.
• Know that a proxy consumes threads from the allotted connections in Apache. Therefore, the available Apache pool might be overwhelmed when the web service that is proxied to is slow or unavailable.

Acquia recommends that you review and accept these risks and consider other solutions.