HTTPS

Create an HTTPS listener on your agentgateway proxy so that your proxy listens for secured HTTPS traffic.

Before you begin

  1. Deploy the httpbin sample app.

  2. Make sure that you have the OpenSSL version of openssl, not LibreSSL. The openssl version must be at least 1.1.

    1. Check the openssl version that is installed. If you see LibreSSL in the output, continue to the next step.

      openssl version
    2. Install the OpenSSL version (not LibreSSL). For example, you might use Homebrew.

      brew install openssl
    3. Review the output of the OpenSSL installation for the path of the binary file. You can choose to export the binary to your path, or call the entire path whenever the following steps use an openssl command.

      • For example, openssl might be installed along the following path: /usr/local/opt/openssl@3/bin/
      • To run commands, you can append the path so that your terminal uses this installed version of OpenSSL, and not the default LibreSSL. /usr/local/opt/openssl@3/bin/openssl req -new -newkey rsa:4096 -x509 -sha256 -days 3650...
  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: To use ListenerSets, you must install the experimental channel of the Kubernetes Gateway API.

    kubectl apply --server-side -f https://github.com/kubernetes-sigs/gateway-api/releases/download/v1.4.0/experimental-install.yaml

    You must also ensure that you installed agentgateway with the --set controller.extraEnv.KGW_ENABLE_GATEWAY_API_EXPERIMENTAL_FEATURES=true Helm flag to use experimental Kubernetes Gateway API features. For an example, see the Get started guide.

Create a TLS certificate

  1. Create a directory to store your TLS credentials in.

    mkdir example_certs
  2. Create a self-signed root certificate. The following command creates a root certificate that is valid for a year and can serve any hostname. You use this certificate to sign the server certificate for the gateway later. For other command options, see the OpenSSL docs.

    # root cert
    openssl req -x509 -sha256 \
    -nodes -days 365 \
    -newkey rsa:2048 \
    -subj '/O=any domain/CN=*' \
    -keyout example_certs/root.key \
    -out example_certs/root.crt
  3. Create an OpenSSL configuration that matches the HTTPS hostname you plan to use. This example assumes that you want to use example.com as your domain. To use a different one, replace every example.com reference with the base domain that you want your listener to serve.

    cat <<'EOF' > example_certs/gateway.cnf
    [ req ]
    default_bits = 2048
    prompt = no
    default_md = sha256
    distinguished_name = dn
    req_extensions = req_ext
    [ dn ]
    CN = *.example.com
    O = any domain
    [ req_ext ]
    subjectAltName = @alt_names
    [ alt_names ]
    DNS.1 = *.example.com
    DNS.2 = example.com
    EOF
  4. Use the configuration and root certificate to create and sign the gateway certificate.

    openssl req -new -nodes -keyout example_certs/gateway.key -out example_certs/gateway.csr -config example_certs/gateway.cnf
    openssl x509 -req -sha256 -days 365 \
      -CA example_certs/root.crt -CAkey example_certs/root.key -set_serial 0 \
      -in example_certs/gateway.csr -out example_certs/gateway.crt \
      -extfile example_certs/gateway.cnf -extensions req_ext
  5. Create a Kubernetes secret to store your server TLS certificate. You create the secret in the same cluster and namespace that the gateway will be deployed to.

    kubectl create secret tls -n agentgateway-system https \
      --key example_certs/gateway.key \
      --cert example_certs/gateway.crt
    kubectl label secret https example=httpbin-https --namespace agentgateway-system

Set up an HTTPS listener

Set up an HTTPS listener on your Gateway.

  1. Create a Gateway resource with an HTTPS listener. The following Gateway listener terminates incoming TLS traffic on port 443 by using the TLS certificates that you created earlier.

    kubectl apply -f- <<EOF
    apiVersion: gateway.networking.k8s.io/v1
    kind: Gateway
    metadata:
      name: https
      namespace: agentgateway-system
      labels:
        example: httpbin-https
    spec:
      gatewayClassName: agentgateway
      listeners:
      - protocol: HTTPS
        port: 443
        name: https
        tls:
          mode: Terminate
          certificateRefs:
            - name: https
              kind: Secret
        allowedRoutes:
          namespaces:
            from: All
    EOF

    Review the following table to understand this configuration.

    Setting Description
    spec.gatewayClassName The name of the Kubernetes GatewayClass that you want to use to configure the Gateway. When you set up agentgateway, a default GatewayClass is set up for you.
    spec.listeners Configure the listeners for this Gateway. The Gateway can serve HTTPS routes from any namespace.
    spec.listeners.tls.mode The TLS mode that you want to use for incoming requests. In this example, HTTPS requests are terminated at the Gateway and the unencrypted request is forwarded to the service in the cluster.
    spec.listeners.tls.certificateRefs The Kubernetes secret that holds the TLS certificate and key for the Gateway. The Gateway uses these credentials to establish the TLS connection with a client, and to decrypt incoming HTTPS requests.
    1. Create a Gateway that enables the attachment of ListenerSets.

      kubectl apply -f- <<EOF
      apiVersion: gateway.networking.k8s.io/v1
      kind: Gateway
      metadata:
        name: https
        namespace: agentgateway-system
        labels:
          example: httpbin-https
      spec:
        gatewayClassName: agentgateway
        allowedListeners:
          namespaces:
            from: All        
        listeners:
        - protocol: HTTP
          port: 80
          name: http-mock
          allowedRoutes:
            namespaces:
              from: All
      EOF

      Review the following table to understand this configuration.

      Setting Description
      spec.gatewayClassName The name of the Kubernetes GatewayClass that you want to use to configure the Gateway. When you set up agentgateway, a default GatewayClass is set up for you.
      spec.allowedListeners Enable the attachment of ListenerSets to this Gateway. The example allows listeners from any namespace, which is helpful in multitenant environments. You can also limit the allowed listeners. To limit to listeners in the same namespace as the Gateway, set this value to Same. To limit to listeners with a particular label, set this value to Selector.
      spec.listeners Optionally, you can configure a listener that is specific to the Gateway. Note that due to a Gateway API limitation, you must configure at least one listener on the Gateway resource, even if the listener is not used and is a generic, “mock” listener. This generic listener cannot conflict with the listener that you configure in the ListenerSet, such as using the same port or name. In this example, the generic listener is configured on port 80, which differs from port 443 in the ListenerSet that you create later.
    2. Create a ListenerSet that configures an HTTPS listener for the Gateway.

      kubectl apply -f- <<EOF
      apiVersion: gateway.networking.x-k8s.io/v1alpha1
      kind: XListenerSet
      metadata:
        name: my-https-listenerset
        namespace: agentgateway-system
        labels:
          example: httpbin-https
      spec:
        parentRef:
          name: https
          namespace: agentgateway-system
          kind: Gateway
          group: gateway.networking.k8s.io
        listeners:
        - protocol: HTTPS
          port: 443
          hostname: https.example.com
          name: https-listener-set
          tls:
            mode: Terminate
            certificateRefs:
              - name: https
                kind: Secret
          allowedRoutes:
            namespaces:
              from: All
      EOF

      Review the following table to understand this configuration.

      Setting Description
      spec.parentRef The name of the Gateway to attach the ListenerSet to.
      spec.listeners Configure the listeners for this ListenerSet. In this example, you configure an HTTPS gateway that listens for incoming traffic for the https.example.com domain on port 443. The gateway can serve HTTP routes from any namespace.
      spec.listeners.tls.mode The TLS mode that you want to use for incoming requests. In this example, HTTPS requests are terminated at the gateway and the unencrypted request is forwarded to the service in the cluster.
      spec.listeners.tls.certificateRefs The Kubernetes secret that holds the TLS certificate and key for the gateway. The gateway uses these credentials to establish the TLS connection with a client, and to decrypt incoming HTTPS requests.
  2. Check the status of the Gateway to make sure that your configuration is accepted. Note that in the output, a NoConflicts status of False indicates that the Gateway is accepted and does not conflict with other Gateway configuration.

    kubectl get gateway https -n agentgateway-system -o yaml
  3. Create an HTTPRoute resource for the httpbin app that is served by the Gateway or ListenerSet that you created.

    kubectl apply -f- <<EOF
    apiVersion: gateway.networking.k8s.io/v1
    kind: HTTPRoute
    metadata:
      name: httpbin-https
      namespace: httpbin
      labels:
        example: httpbin-https
    spec:
      hostnames:
        - https.example.com
      parentRefs:
        - name: https
          namespace: agentgateway-system
      rules:
        - backendRefs:
            - name: httpbin
              port: 8000
    EOF
    kubectl apply -f- <<EOF
    apiVersion: gateway.networking.k8s.io/v1
    kind: HTTPRoute
    metadata:
      name: httpbin-https
      namespace: httpbin
      labels:
        example: httpbin-https
    spec:
      parentRefs:
        - name: my-https-listenerset
          namespace: agentgateway-system
          kind: XListenerSet
          group: gateway.networking.x-k8s.io
      rules:
        - backendRefs:
            - name: httpbin
              port: 8000
    EOF
  4. Verify that the HTTPRoute is applied successfully.

    kubectl get httproute/httpbin-https -n httpbin -o yaml

    Example output: Notice in the status section that the parentRef is either the Gateway or the ListenerSet, depending on how you attached the HTTPRoute.

    ...
    status:
    ...
      parentRef:
        group: gateway.networking.k8s.io
        kind: Gateway
        name: https
        namespace: agentgateway-system
  5. Verify that the listener now has a route attached.

    kubectl get gateway -n agentgateway-system https -o yaml

    Example output:

    ...
    listeners:
    - attachedRoutes: 1
    kubectl get xlistenerset -n agentgateway-system my-https-listenerset -o yaml

    Example output:

    ...
    listeners:
    - attachedRoutes: 1

    Note that because the HTTPRoute is attached to the ListenerSet, the Gateway does not show the route in its status.

    kubectl get gateway -n agentgateway-system https -o yaml

    Example output:

    ...
    listeners:
    - attachedRoutes: 0

    If you create another HTTPRoute that attaches to the Gateway and uses the same listener as the ListenerSet, then the route is reported in the status of both the Gateway (attachedRoutes: 1) and the ListenerSet (attachedRoutes: 2).

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

    export INGRESS_GW_ADDRESS=$(kubectl get svc -n agentgateway-system https -o jsonpath="{.status.loadBalancer.ingress[0]['hostname','ip']}")
    echo $INGRESS_GW_ADDRESS   
    kubectl port-forward svc/https -n agentgateway-system 8443:443

  7. Send a request to the httpbin app and verify that you see the TLS handshake and you get back a 200 HTTP response code.

    curl -vik --resolve "https.example.com:443:${INGRESS_GW_ADDRESS}" https://https.example.com:443/status/200
    curl -vik --connect-to https.example.com:443:localhost:8443 https://https.example.com:443/status/200

    Example output:

    * Added https.example.com:443:172.18.0.5 to DNS cache
    * Hostname https.example.com was found in DNS cache
    *   Trying 172.18.0.5:443...
    * Connected to https.example.com (172.18.0.5) port 443
    * ALPN: curl offers h2,http/1.1
    * (304) (OUT), TLS handshake, Client hello (1):
    * (304) (IN), TLS handshake, Server hello (2):
    * (304) (IN), TLS handshake, Unknown (8):
    * (304) (IN), TLS handshake, Certificate (11):
    * (304) (IN), TLS handshake, CERT verify (15):
    * (304) (IN), TLS handshake, Finished (20):
    * (304) (OUT), TLS handshake, Finished (20):
    * SSL connection using TLSv1.3 / AEAD-AES256-GCM-SHA384 / [blank] / UNDEF
    * ALPN: server accepted h2
    * Server certificate:
    *  subject: CN=*.example.com; O=any domain
    *  issuer: O=any domain; CN=*
    *  SSL certificate verify result: unable to get local issuer certificate (20), continuing anyway.
    * using HTTP/2
    * [HTTP/2] [1] OPENED stream for https://https.example.com:443/status/200
    * [HTTP/2] [1] [:method: GET]
    * [HTTP/2] [1] [:scheme: https]
    * [HTTP/2] [1] [:authority: https.example.com]
    * [HTTP/2] [1] [:path: /status/200]
    * [HTTP/2] [1] [user-agent: curl/8.7.1]
    * [HTTP/2] [1] [accept: */*]
    > GET /status/200 HTTP/2
    > Host: https.example.com
    > User-Agent: curl/8.7.1
    > Accept: */*
    > 
    * Request completely sent off
    < HTTP/2 200 
    HTTP/2 200 
    ...

Cleanup

You can remove the resources that you created in this guide.
kubectl delete -A gateways,httproutes,secret -l example=httpbin-https
rm -rf example_certs
kubectl delete -A gateways,httproutes,xlistenersets,secret -l example=httpbin-https
rm -rf example_certs
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