You might have services in your Kubernetes cluster that use HTTP/2 for communication. Typically these are gRPC services, but it could apply to any service that uses HTTP/2 in its transport layer. To enable HTTP/2 communication, the spec.useHttp2 value for the Upstream must be set to true. This setting instructs Gloo Gateway to use HTTP/2 for communication with the destination.

Explore your options for how to add the spec.useHttp2 value to your Upstream resource.

Before you begin

  1. Follow the Get started guide to install Gloo Gateway, set up a gateway resource, and deploy the httpbin sample app.

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

      export INGRESS_GW_ADDRESS=$(kubectl get svc -n gloo-system gloo-proxy-http -o jsonpath='{.status.loadBalancer.ingress[0].ip}')
echo $INGRESS_GW_ADDRESS  
  
      export INGRESS_GW_ADDRESS=$(kubectl get svc -n gloo-system gloo-proxy-http -o jsonpath='{.status.loadBalancer.ingress[0].hostname}')
echo $INGRESS_GW_ADDRESS
  
      kubectl port-forward deployment/gloo-proxy-http -n gloo-system 8080:8080

Enable on the Upstream

You can add the spec.useHttp2 setting to an Upstream directly.

  1. Edit the Upstream that was created for the httpbin app.

      kubectl edit upstream httpbin-httpbin-8000 -n gloo-system

  2. Add the spec.useHttp2 setting as shown in the following example.

       apiVersion: gloo.solo.io/v1
   kind: Upstream
   metadata:
     annotations:
       gloo.solo.io/h2_service: "true"
       kubectl.kubernetes.io/last-applied-configuration: |
         {"apiVersion":"v1","kind":"Service","metadata":{"annotations":{},"labels":{"app":"httpbin","service":"httpbin"},"name":"httpbin","namespace":"httpbin"},"spec":{"ports":[{"name":"http","port":8000,"targetPort":8080},{"name":"tcp","port":9000}],"selector":{"app":"httpbin"}}}
     creationTimestamp: "2024-04-26T20:34:49Z"
     generation: 4
     labels:
       discovered_by: kubernetesplugin
     name: httpbin-httpbin-8000
     namespace: gloo-system
     resourceVersion: "4421071"
     uid: a73b1b82-2910-497a-9f82-ff513ebe911d
   spec:
     discoveryMetadata:
       labels:
         app: httpbin
         service: httpbin
     kube:
       selector:
         app: httpbin
       serviceName: httpbin
       serviceNamespace: httpbin
       servicePort: 8000
     useHttp2: true

  3. Optional: Remove the useHttp2 setting from your Upstream by editing the Upstream and removing the setting.

      kubectl edit upstream httpbin-httpbin-8000 -n gloo-system

Enable with service annotations

One of the ways to enable HTTP/2, is to add the gloo.solo.io/h2_service annotation to the Kubernetes service and set it to true. If the annotation is present, Gloo Gateway automatically updates the Upstream and adds the useHttp2 value.

  1. Review the httpbin Upstream resource that was automatically created for the httpbin app that you deployed as part of the Get started guide. Note that the spec.useHttp2 option is not set.

      kubectl get upstream httpbin-httpbin-8000 -n gloo-system -o yaml

  2. Add the gloo.solo.io/h2_service=true annotation to the httpbin service.

      kubectl annotate service httpbin gloo.solo.io/h2_service=true -n httpbin

  3. Review the httpbin Upstream again and verify that you now see the useHttp2: true setting on your Upstream.

      kubectl get upstream httpbin-httpbin-8000 -n gloo-system -o yaml

    Example output:

       apiVersion: gloo.solo.io/v1
   kind: Upstream
   metadata:
     annotations:
       gloo.solo.io/h2_service: "true"
       kubectl.kubernetes.io/last-applied-configuration: |
         {"apiVersion":"v1","kind":"Service","metadata":{"annotations":{},"labels":{"app":"httpbin","service":"httpbin"},"name":"httpbin","namespace":"httpbin"},"spec":{"ports":[{"name":"http","port":8000,"targetPort":8080},{"name":"tcp","port":9000}],"selector":{"app":"httpbin"}}}
     creationTimestamp: "2024-04-26T20:34:49Z"
     generation: 4
     labels:
       discovered_by: kubernetesplugin
     name: httpbin-httpbin-8000
     namespace: gloo-system
     resourceVersion: "4421071"
     uid: a73b1b82-2910-497a-9f82-ff513ebe911d
   spec:
     discoveryMetadata:
       labels:
         app: httpbin
         service: httpbin
     kube:
       selector:
         app: httpbin
       serviceName: httpbin
       serviceNamespace: httpbin
       servicePort: 8000
     useHttp2: true

  4. Update the annotation on the httpbin service and set it to false.

      kubectl annotate service httpbin gloo.solo.io/h2_service=false -n httpbin --overwrite

  5. Review the Upstream resource again and verify that the useHttp2 setting was updated to false.

      kubectl get upstream httpbin-httpbin-8000 -n gloo-system -o yaml

    Example output:

       ...
   spec:
    discoveryMetadata:
      labels:
        app: httpbin
        service: httpbin
    kube:
      selector:
        app: httpbin
      serviceName: httpbin
      serviceNamespace: httpbin
      servicePort: 8000
    useHttp2: false

Enable with port names

You can enable HTTP/2 by setting specific port names on the service that exposes the Upstream. The name of the port must be one of the following: grpc, http2, or h2.

  1. Review the httpbin Upstream resource that was automatically created for the httpbin app that you deployed as part of the Get started guide. Note that the spec.useHttp2 option is not set.

      kubectl get upstream httpbin-httpbin-8000 -n gloo-system -o yaml

  2. Review the ports that are defined on the httpbin service.

      kubectl get service httpbin -n httpbin -o yaml

    Example output:

       ...
   spec:
     clusterIP: 172.20.148.195
     clusterIPs:
     - 172.20.148.195
     internalTrafficPolicy: Cluster
     ipFamilies:
     - IPv4
     ipFamilyPolicy: SingleStack
     ports:
     - name: http
       port: 8000
       protocol: TCP
       targetPort: 8080
     - name: tcp
       port: 9000
       protocol: TCP
       targetPort: 9000

  3. Edit the service and change the http port to http2.

      kubectl edit service httpbin -n httpbin

    Example output:

       ...
   spec:
     clusterIP: 172.20.148.195
     clusterIPs:
     - 172.20.148.195
     internalTrafficPolicy: Cluster
     ipFamilies:
     - IPv4
     ipFamilyPolicy: SingleStack
     ports:
     - name: http2
       port: 8000
       protocol: TCP
       targetPort: 8080
     - name: tcp
       port: 9000
       protocol: TCP
       targetPort: 9000

  4. Review the Upstream for the httpbin app and verify that the useHttp2 setting was added.

      kubectl get upstream httpbin-httpbin-8000 -n gloo-system -o yaml

    Example output:

       ...
   spec:
    discoveryMetadata:
      labels:
        app: httpbin
        service: httpbin
    kube:
      selector:
        app: httpbin
      serviceName: httpbin
      serviceNamespace: httpbin
      servicePort: 8000
    useHttp2: true