> **FastCGI** is a [binary protocol](https://en.wikipedia.org/wiki/Binary_protocol "Binary protocol") for interfacing interactive programs with a [web server](https://en.wikipedia.org/wiki/Web_server "Web server"). [...] (It's) aim is to reduce the overhead related to interfacing between web server and CGI programs, allowing a server to handle more web page requests per unit of time.
The _ingress-nginx_ ingress controller can be used to directly expose [FastCGI](https://en.wikipedia.org/wiki/FastCGI) servers. Enabling FastCGI in your Ingress only requires setting the _backend-protocol_ annotation to `FCGI`, and with a couple more annotations you can customize the way _ingress-nginx_ handles the communication with your FastCGI _server_.
For most practical use-cases, php applications are a good example. PHP is not HTML so a FastCGI server like php-fpm processes a index.php script for the response to a request. See a working example below.
This [post in a FactCGI feature issue](https://github.com/kubernetes/ingress-nginx/issues/8207#issuecomment-2161405468) describes a test for the FastCGI feature. The same test is described below here.
- For this example to work, a HTML response should be received from the FastCGI server being exposed
- A HTTP request to the FastCGI server pod should be sent
- The response should be generated by a php script as that is what we are demonstrating here
The image we are using here `php:fpm-alpine` does not ship with a ready to use php script inside it. So we need to provide the image with a simple php-script for this example to work.
- Use `kubectl exec` to get into the example-app pod
- You will land at the path `/var/www/html`
- Create a simple php script there at the path /var/www/html called index.php
- Make the index.php file look like this
```
<!DOCTYPE html>
<html>
<head>
<title>PHP Test</title>
</head>
<body>
<?php echo '<p>FastCGI Test Worked!</p>'; ?>
</body>
</html>
```
- Save and exit from the shell in the pod
- If you delete the pod, then you will have to recreate the file as this method is not persistent
The _Ingress_ and _ConfigMap_ objects below demonstrate the supported _FastCGI_ specific annotations.
!!! Important
NGINX actually has 50 [FastCGI directives](https://nginx.org/en/docs/http/ngx_http_fastcgi_module.html#directives)
All of the nginx directives have not been exposed in the ingress yet
### The ConfigMap object
This configMap object is required to set the parameters of [FastCGI directives](https://nginx.org/en/docs/http/ngx_http_fastcgi_module.html#directives)
You will have to look at the external-ip of the ingress or you have to send the HTTP request to the ClusterIP address of the ingress-nginx controller pod.
**This enables the _FastCGI_ mode for all paths defined in the _Ingress_ object**
### The `nginx.ingress.kubernetes.io/fastcgi-index` Annotation
To specify an index file, the `fastcgi-index` annotation value can optionally be set. In the example below, the value is set to `index.php`. This annotation corresponds to [the _NGINX_ `fastcgi_index` directive](https://nginx.org/en/docs/http/ngx_http_fastcgi_module.html#fastcgi_index).
### The `nginx.ingress.kubernetes.io/fastcgi-params-configmap` Annotation
To specify [_NGINX_ `fastcgi_param` directives](https://nginx.org/en/docs/http/ngx_http_fastcgi_module.html#fastcgi_param), the `fastcgi-params-configmap` annotation is used, which in turn must lead to a _ConfigMap_ object containing the _NGINX_`fastcgi_param` directives as key/values.
