Envoy as an API Gateway in Kubernetes¶
A common scenario for using Envoy is deploying it as an edge service (API Gateway) in Kubernetes. Ambassador is an open source distribution of Envoy designed for Kubernetes. Ambassador uses Envoy for all L4/L7 management and Kubernetes for reliability, availability, and scalability. Ambassador operates as a specialized control plane to expose Envoy’s functionality as Kubernetes annotations.
This example will walk through how you can deploy Envoy on Kubernetes via Ambassador.
Ambassador is configured via Kubernetes deployments. To install Ambassador/Envoy on Kubernetes, run the following if you’re using a cluster with RBAC enabled:
kubectl apply -f https://www.getambassador.io/yaml/ambassador/ambassador-rbac.yaml
or this if you are not using RBAC:
kubectl apply -f https://www.getambassador.io/yaml/ambassador/ambassador-no-rbac.yaml
The above YAML will create a Kubernetes deployment for Ambassador that includes readiness and liveness checks. By default, it will also create 3 instances of Ambassador. Each Ambassador instance consists of an Envoy proxy along with the Ambassador control plane.
We’ll now need to create a Kubernetes service to point to the Ambassador
deployment. In this example, we’ll use a
LoadBalancer service. If your
cluster doesn’t support
LoadBalancer services, you’ll need to change to a
--- apiVersion: v1 kind: Service metadata: labels: service: ambassador name: ambassador spec: type: LoadBalancer ports: - port: 80 targetPort: 80 selector: service: ambassador
Save this YAML to a file
ambassador-svc.yaml. Then, deploy this service to
kubectl apply -f ambassador-svc.yaml
At this point, Envoy is now running on your cluster, along with the Ambassador control plane.
Ambassador uses Kubernetes annotations to add or remove configuration. This sample YAML will add a route to Google, similar to the basic configuration example in the Getting Started guide.
--- apiVersion: v1 kind: Service metadata: name: google annotations: getambassador.io/config: | --- apiVersion: ambassador/v0 kind: Mapping name: google_mapping prefix: /google/ service: https://google.com:443 host_rewrite: www.google.com spec: type: ClusterIP clusterIP: None
Save the above into a file called
google.yaml. Then run:
kubectl apply -f google.yaml
Ambassador will detect the change to your Kubernetes annotation and add the route to Envoy. Note that we used a dummy service in this example; typically, you would associate the annotation with your real Kubernetes service.
Testing the mapping¶
You can test this mapping by getting the external IP address for the Ambassador
service, and then sending a request via
$ kubectl get svc ambassador NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE ambassador 10.19.241.98 126.96.36.199 80:32491/TCP 15m $ curl -v 188.8.131.52/google/