HTTP/1.0 and HTTP/0.9

Configure your gateway proxy to accept older HTTP protocols.

About HTTP/1.0 and HTTP/0.9

By default, Envoy-based gateway proxies return a 426 Upgrade Required HTTP response code for HTTP/1.0 and HTTP/0.9 requests. HTTP/0.9 was a simple, rudimentary protocol that was introduced in 1991 and supported only the GET HTTP method. Other methods, such as POST, PUT, and DELETE were later introduced in HTTP/1.0.

Both protocol versions are rarely used nowadays. However, some applications might still require support for these versions for backwards compatibililty. To allow the gateway proxy to accept these types of requests, you can create an HTTPListenerPolicy and attach it to your Gateway.

Before you begin

1. Follow the Get started guide to install kgateway.

2. Deploy a sample httpbin app.

3. Decide whether to set up a listener inline on the Gateway resource or as a separate ListenerSet resource. For more information, see the Listener overview.

   ListenerSets: This feature is available in kgateway version 2.1.x or later. Also, you must install the experimental channel of the Kubernetes Gateway API at version 1.3 or later.

Set up HTTP 1.0 support

1. Create an HTTPListenerPolicy with the acceptHttp10 field. In the targetRefs, attach the policy to the Gateway that you want to support the HTTP/1.0 protocol.

   kubectl apply -f- <<EOF
   apiVersion: gateway.kgateway.dev/v1alpha1
   kind: HTTPListenerPolicy
   metadata:
     name: accept-http10
     namespace: kgateway-system
   spec:
     targetRefs:
     - group: gateway.networking.k8s.io
       kind: Gateway
       name: http
     acceptHttp10: true
   EOF

2. Port-forward the gateway proxy on port 19000 to open the Envoy admin interface.

   kubectl port-forward deploy/http -n kgateway-system 19000

3. Open the Envoy admin interface and look for the http_protocol_options filter in your Envoy filter chain. Then, verify that the accept_http_10 field is set to true.

   Example output:

   "http_protocol_options": {
             "accept_http_10": true
      }
   

Cleanup

kubectl delete httplistenerpolicy accept-http10 -n kgateway-system