L7 Path Translation
This example replicates the Prometheus metrics listener which is
already available via the command line option
So the point of this example is not to add new functionality, but to show
how a feature that previously required Cilium Agent code changes can be
implemented with the new Cilium Envoy Config CRD.
Apply Example CRD
This example adds a new Envoy listener
on the standard Prometheus port (e.g.
9090) to each Cilium node, translating
the default Prometheus metrics path
/metrics to Envoy’s Prometheus metrics path
Apply this Cilium Envoy Config CRD:
$ kubectl apply -f https://raw.githubusercontent.com/cilium/cilium/1.14.4/examples/kubernetes/servicemesh/envoy/envoy-prometheus-metrics-listener.yaml
This version of the
CiliumClusterwideEnvoyConfig CRD is Cluster-scoped,
(i.e., not namespaced), so the name needs to be unique in the cluster,
unless you want to replace a CRD with a new one.
Note that these Envoy resources are not validated by K8s at all, so
any errors in the Envoy resources will only be seen by the Cilium
Agent observing these CRDs. This means that
kubectl apply will
report success, while parsing and/or installing the resources for the
node-local Envoy instance may have failed. Currently the only way of
verifying this is by observing Cilium Agent logs for errors and
warnings. Additionally, Cilium Agent will print warning logs for any
conflicting Envoy resources in the cluster.
Note that Cilium Ingress Controller will configure required Envoy resource under the hood. Please check Cilium Agent logs if you are creating Envoy resources explicitly to make sure there is no conflict.
$ kubectl logs -n kube-system ds/cilium | grep -E "level=(error|warning)"
Test the Listener Port
Test that the new port is responding to the metrics requests:
$ curl http://<node-IP>:9090/metrics
<node-IP> is the IP address of one of your k8s cluster nodes.
Remove the prometheus listener with:
$ kubectl delete -f https://raw.githubusercontent.com/cilium/cilium/1.14.4/examples/kubernetes/servicemesh/envoy/envoy-prometheus-metrics-listener.yaml