Description

A listener is not being created for a UDP port on the Envoy Proxy, whereas TCP/HTTP listeners work as expected. This may be related to the use of a DaemonSet (the configuration has not yet been tested with a Deployment). Notably, the Envoy Proxy Service is updated with the correct UDP port, which suggests that Envoy Gateway is processing the configuration and recognizing the port.

There are no errors in the logs from either Envoy Gateway or Envoy Proxy. Based on this and the fact that the UDP listener is absent from the config dump, it appears that Envoy Gateway is not even attempting to configure a listener for this UDP port.

Reproduction Steps

Create a Gateway and UDPRoute as shown below:

apiVersion: gateway.networking.k8s.io/v1
kind: Gateway
metadata:
  name: gateway
spec:
  gatewayClassName: envoy-gateway-class
  listeners:
    - name: 21110-udp
      port: 21110
      protocol: UDP
      allowedRoutes:
        kinds:
          - kind: UDPRoute
        namespaces:
          from: Same

Environment

Envoy Gateway Version (Latest): docker.io/envoyproxy/gateway-dev@sha256:e8beabddf486ca0878bb8a7e935c716e046e6e7560ed1c8cf4dac224a3ae557f
Deployment Type: DaemonSet (not tested with Deployment)

Observed Behavior

• The Service for Envoy Proxy includes the UDP port as expected.
• The Envoy admin interface (/config_dump) does not show a UDP listener under type.googleapis.com/envoy.admin.v3.ListenersConfigDump.
• There are no errors in the logs of either Envoy Gateway or Envoy Proxy that reference the UDP listener or port.

Expected Behavior

A UDP listener should be created and appear in the listener config dump. If there is a reason the listener is not being created (e.g. a misconfiguration or unsupported scenario), an error or warning should be emitted by Envoy Gateway.