fixed fastcgi userguide (#11454)

kubernetes · Jun 12, 2024 · 8ca27e7 · 8ca27e7
1 parent 4038211
commit 8ca27e7
Showing 1 changed file with 101 additions and 11 deletions.
diff --git a/docs/user-guide/fcgi-services.md b/docs/user-guide/fcgi-services.md
@@ -1,5 +1,3 @@
-
-
 # Exposing FastCGI Servers
 
 > **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.
@@ -8,10 +6,15 @@
 
 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.
+
+## Example Objects to expose a FastCGI server pod
 
-## Example Objects to Expose a FastCGI Pod
+### The FasctCGI server pod
 
-The _Pod_ example object below exposes port `9000`, which is the conventional FastCGI port.
+The _Pod_ object example below exposes port `9000`, which is the conventional FastCGI port.
 
 ```yaml
 apiVersion: v1
@@ -23,12 +26,40 @@ labels:
 spec:
   containers:
   - name: example-app
-    image: example-app:1.0
+    image: php:fpm-alpine
     ports:
     - containerPort: 9000
       name: fastcgi
 ```
 
+- 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 FastCGI service
+
 The _Service_ object example below matches port `9000` from the _Pod_ object above.
 
 ```yaml
@@ -45,21 +76,41 @@ spec:
     name: fastcgi
 ```
 
-And the _Ingress_ and _ConfigMap_ objects below demonstrates the supported _FastCGI_ specific annotations (NGINX actually has 50 FastCGI directives, all of which have not been exposed in the ingress yet), and matches the service `example-service`, and the port named `fastcgi` from above. The _ConfigMap_ **must** be created first for the _Ingress Controller_ to be able to find it when the _Ingress_ object is created, otherwise you will need to restart the _Ingress Controller_ pods.
+### The configMap object and the ingress object
 
-```yaml
-# The ConfigMap MUST be created first for the ingress controller to be able to
-# find it when the Ingress object is created.
+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)
 
+!!! Attention
+    - The _ConfigMap_ **must** be created before creating the ingress object
+
+- The _Ingress Controller_ needs to find the configMap when the _Ingress_ object with the FastCGI annotations is created
+- So create the configMap before the ingress
+- If the configMap is created after the ingress is created, then you will need to restart the _Ingress Controller_ pods.
+
+```yaml
 apiVersion: v1
 kind: ConfigMap
 metadata:
   name: example-cm
 data:
-  SCRIPT_FILENAME: "/example/index.php"
+  SCRIPT_FILENAME: "/var/www/html/index.php"
 
----
+```
+
+### The ingress object
 
+- Do not create the ingress shown below until you have created the configMap seen above.
+- You can see that this ingress matches the service `example-service`, and the port named `fastcgi` from above.
+
+```
 apiVersion: networking.k8s.io/v1
 kind: Ingress
 metadata:
@@ -83,6 +134,44 @@ spec:
               name: fastcgi
 ```
 
+## Send a request to the exposed FastCGI server
+
+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.
+
+```
+% curl 172.19.0.2 -H "Host: app.example.com" -vik
+*   Trying 172.19.0.2:80...
+* Connected to 172.19.0.2 (172.19.0.2) port 80
+> GET / HTTP/1.1
+> Host: app.example.com
+> User-Agent: curl/8.6.0
+> Accept: */*
+> 
+< HTTP/1.1 200 OK
+HTTP/1.1 200 OK
+< Date: Wed, 12 Jun 2024 07:11:59 GMT
+Date: Wed, 12 Jun 2024 07:11:59 GMT
+< Content-Type: text/html; charset=UTF-8
+Content-Type: text/html; charset=UTF-8
+< Transfer-Encoding: chunked
+Transfer-Encoding: chunked
+< Connection: keep-alive
+Connection: keep-alive
+< X-Powered-By: PHP/8.3.8
+X-Powered-By: PHP/8.3.8
+
+< 
+<!DOCTYPE html>
+<html>
+    <head>
+        <title>PHP Test</title>
+    </head>
+    <body>
+        <p>FastCGI Test Worked</p>    </body>
+</html>
+
+```
+
 ## FastCGI Ingress Annotations
 
 To enable FastCGI, the `nginx.ingress.kubernetes.io/backend-protocol` annotation needs to be set to `FCGI`, which overrides the default `HTTP` value.
@@ -114,6 +203,7 @@ data:
   SCRIPT_FILENAME: "/example/index.php"
   HTTP_PROXY: ""
 ```
+
 Using the _namespace/_ prefix is also supported, for example:
 
 > `nginx.ingress.kubernetes.io/fastcgi-params-configmap: "example-namespace/example-configmap"`