Gateway health checks

Documentation

Health checks

Enable a health check plugin on your gateway proxy to respond with common HTTP codes.

About

K8sGateway 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

Follow the Get started guide to install K8sGateway, set up a gateway resource, and deploy the httpbin sample app.

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

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

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
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>
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
```
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>
Stop port-forwarding the gloo-gateway-http deployment.
```
lsof -ti:19000 | xargs kill -9
```

Cleanup

You can remove the resources that you created in this guide.

kubectl delete HttpListenerOption healthcheck -n gloo-system

Upstream health checks