diff --git a/pkg/registry/core/service/portallocator/allocator.go b/pkg/registry/core/service/portallocator/allocator.go
--- a/pkg/registry/core/service/portallocator/allocator.go	(revision f66044f4361b9f1f96f0053dd46cb7dce5e990a8)
+++ b/pkg/registry/core/service/portallocator/allocator.go	(revision f42349f2a3ed203fc06462b9f28e90c0b857cb42)
@@ -25,6 +25,7 @@
 	"k8s.io/kubernetes/pkg/registry/core/service/allocator"

 	"k8s.io/klog/v2"
+	"source.monogon.dev/metropolis/node"
 )

 // Interface manages the allocation of ports out of a range. Interface
@@ -70,6 +71,12 @@
 	}
 	var err error
 	a.alloc, err = allocatorFactory(max, rangeSpec)
+
+	for _, p := range node.SystemPorts {
+		// We ignore errors as these could only happen if the port we try to
+		// allocate is out of range, which we dont really care about.
+		_, _ = a.alloc.Allocate(int(p))
+	}
 	return a, err
 }