Buffering

Fine-tune connection speeds for read and write operations.

About read and write buffer limits

By default, kgateway is set up with 1MiB of request read and write buffer for each gateway listener. For large requests that must be buffered and that exceed the default buffer limit, kgateway either disconnects the connection to the downstream service if headers were already sent, or returns a 500 HTTP response code. To make sure that large requests can be sent and received, you can specify the maximum number of bytes that can be buffered between the gateway and the downstream service.

Before you begin

1. Follow the Get started guide to install kgateway.

2. Follow the Sample app guide to create an API gateway proxy with an HTTP listener and deploy the httpbin sample app.

3. Get the external address of the gateway and save it in an environment variable.

   Cloud Provider LoadBalancerPort-forward for local testing

   export INGRESS_GW_ADDRESS=$(kubectl get svc -n kgateway-system http -o jsonpath="{.status.loadBalancer.ingress[0]['hostname','ip']}")
   echo $INGRESS_GW_ADDRESS  

   kubectl port-forward deployment/http -n kgateway-system 8080:8080

Set up connection buffer limits

1. Create a ListenerPolicy resource to define your connection buffer limit rules.

   kubectl apply -f- <<EOF
   apiVersion: gateway.kgateway.dev/v1alpha1
   kind: ListenerPolicy
   metadata:
     name: bufferlimits
     namespace: kgateway-system
   spec:
     targetRef:
       group: gateway.networking.k8s.io
       kind: Gateway
       name: http
     perConnectionBufferLimitBytes: 10485760
   EOF

2. Verify that your configuration is applied by reviewing the Envoy configuration.

   1. Port forward the gloo-gateway-http deployment on port 19000.

      kubectl port-forward deploy/http -n kgateway-system 19000 & 
   2. Open the config_dump endpoint.

      open http://localhost:19000/config_dump
   3. Look for the "per_connection_buffer_limit_bytes": 10485760 string in your Envoy configuration.

Cleanup

kubectl delete listenerpolicy bufferlimits -n kgateway-system