About

Gloo Gateway includes an HTTP health checking plug-in that you can enable for a gateway proxy listener. This plug-in responds to health check requests directly with either a 200 OK or 503 Service Unavailable message, depending on the current draining state of Envoy.

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]['hostname','ip']}")
echo $INGRESS_GW_ADDRESS  
  
      kubectl port-forward deployment/gloo-proxy-http -n gloo-system 8080:8080

Configure a health check on a gateway

  1. Create an HTTPListenerOption resource to configure a health check path for the HTTP or HTTPS listener on the gateway. You can define any path, such as /check/healthz.

      kubectl apply -f- <<EOF
apiVersion: gateway.solo.io/v1
kind: HttpListenerOption
metadata:
  name: healthcheck
  namespace: gloo-system
spec:
  targetRefs:
  - group: gateway.networking.k8s.io
    kind: Gateway
    name: http
  options:
    healthCheck:
      path: <path>
EOF

  2. To test the health check, drain the Envoy connections by sending an HTTP POST request to the /healthcheck/fail endpoint of the Envoy admin port.

    1. Port-forward the gloo-gateway-http deployment on port 19000.
        kubectl port-forward deploy/gloo-proxy-http -n gloo-system 19000 &
    2. Send an HTTP POST request to the /healthcheck/fail endpoint. This causes Envoy connections to begin draining.
        curl -X POST 127.0.0.1:19000/healthcheck/fail

  3. Send a request to the health check path. Because Envoy is in a draining state, the 503 Service Unavailable message is returned.

      curl -i $INGRESS_GW_ADDRESS:8080/<path>
  
      curl -i localhost:8080/<path>

  4. After you finish testing, resume Envoy connections by sending an HTTP POST request to the /healthcheck/ok endpoint of the Envoy admin port.

      curl -X POST 127.0.0.1:19000/healthcheck/ok

  5. Send another request to the health check path. Because Envoy is operating normally, the 200 OK message is returned.

      curl -i $INGRESS_GW_ADDRESS:8080/<path>
  
      curl -i localhost:8080/<path>

  6. Stop port-forwarding the gloo-gateway-http deployment.

      lsof -ti:19000 | xargs kill -9

Cleanup

You can optionally remove the resources that you set up as part of this guide.
  kubectl delete HttpListenerOption healthcheck -n gloo-system