metropolis/node/core/metrics: expose etcd metrics

Change-Id: Ie916d497b44c05ab51b13d0bb14f4e850291a77e
Reviewed-on: https://review.monogon.dev/c/monogon/+/1950
Tested-by: Jenkins CI
Reviewed-by: Serge Bazanski <serge@monogon.tech>
diff --git a/metropolis/node/ports.go b/metropolis/node/ports.go
index afa4b1a..40c106f 100644
--- a/metropolis/node/ports.go
+++ b/metropolis/node/ports.go
@@ -47,6 +47,10 @@
 	// runs, bound to 127.0.0.1. The Metrics Service proxies traffic to it from the
 	// public MetricsPort.
 	MetricsNodeListenerPort Port = 7841
+	// MetricsEtcdListenerPort is the TCP port on which the etcd exporter
+	// runs, bound to 127.0.0.1. The Metrics Service proxies traffic to it from the
+	// public MetricsPort.
+	MetricsEtcdListenerPort Port = 7842
 	// KubernetesAPIPort is the TCP port on which the Kubernetes API is
 	// exposed.
 	KubernetesAPIPort Port = 6443
@@ -70,6 +74,7 @@
 	NodeManagement,
 	MetricsPort,
 	MetricsNodeListenerPort,
+	MetricsEtcdListenerPort,
 	KubernetesAPIPort,
 	KubernetesAPIWrappedPort,
 	KubernetesWorkerLocalAPIPort,