diff --git a/osbase/net/dns/kubernetes/BUILD.bazel b/osbase/net/dns/kubernetes/BUILD.bazel
new file mode 100644
index 0000000..a23fc46
--- /dev/null
+++ b/osbase/net/dns/kubernetes/BUILD.bazel
@@ -0,0 +1,43 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
+
+go_library(
+    name = "kubernetes",
+    srcs = [
+        "controller.go",
+        "handler.go",
+        "kubernetes.go",
+        "metrics.go",
+    ],
+    importpath = "source.monogon.dev/osbase/net/dns/kubernetes",
+    visibility = ["//visibility:public"],
+    deps = [
+        "//osbase/net/dns",
+        "//osbase/net/dns/kubernetes/object",
+        "//osbase/supervisor",
+        "@com_github_miekg_dns//:dns",
+        "@com_github_prometheus_client_golang//prometheus",
+        "@io_k8s_api//core/v1:core",
+        "@io_k8s_api//discovery/v1:discovery",
+        "@io_k8s_apimachinery//pkg/apis/meta/v1:meta",
+        "@io_k8s_apimachinery//pkg/runtime",
+        "@io_k8s_apimachinery//pkg/watch",
+        "@io_k8s_client_go//kubernetes",
+        "@io_k8s_client_go//tools/cache",
+    ],
+)
+
+go_test(
+    name = "kubernetes_test",
+    srcs = ["handler_test.go"],
+    embed = [":kubernetes"],
+    deps = [
+        "//osbase/net/dns",
+        "@com_github_miekg_dns//:dns",
+        "@io_k8s_api//core/v1:core",
+        "@io_k8s_api//discovery/v1:discovery",
+        "@io_k8s_apimachinery//pkg/apis/meta/v1:meta",
+        "@io_k8s_apimachinery//pkg/util/intstr",
+        "@io_k8s_client_go//kubernetes/fake",
+        "@io_k8s_utils//ptr",
+    ],
+)
diff --git a/osbase/net/dns/kubernetes/LICENSE-3RD-PARTY.txt b/osbase/net/dns/kubernetes/LICENSE-3RD-PARTY.txt
new file mode 100644
index 0000000..98f9935
--- /dev/null
+++ b/osbase/net/dns/kubernetes/LICENSE-3RD-PARTY.txt
@@ -0,0 +1,13 @@
+Copyright 2016-2024 The CoreDNS authors and contributors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
diff --git a/osbase/net/dns/kubernetes/controller.go b/osbase/net/dns/kubernetes/controller.go
new file mode 100644
index 0000000..61a33fc
--- /dev/null
+++ b/osbase/net/dns/kubernetes/controller.go
@@ -0,0 +1,307 @@
+package kubernetes
+
+// Taken and modified from the Kubernetes plugin of CoreDNS, under Apache 2.0.
+
+import (
+	"context"
+	"errors"
+	"sync/atomic"
+	"time"
+
+	api "k8s.io/api/core/v1"
+	discovery "k8s.io/api/discovery/v1"
+	meta "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/watch"
+	"k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/tools/cache"
+
+	"source.monogon.dev/osbase/net/dns/kubernetes/object"
+)
+
+const (
+	svcIPIndex           = "ServiceIP"
+	epNameNamespaceIndex = "EndpointNameNamespace"
+	epIPIndex            = "EndpointsIP"
+)
+
+// epLabelSelector selects EndpointSlices that belong to headless services.
+// Endpoint DNS records are only served for headless services,
+// and we can save resources by not fetching other EndpointSlices.
+const epLabelSelector = api.IsHeadlessService
+
+type dnsController interface {
+	GetSvc(string) *object.Service
+	SvcIndexReverse(string) []*object.Service
+	EpIndex(string) []*object.Endpoints
+	EpIndexReverse(string) []*object.Endpoints
+	NamespaceExists(string) bool
+
+	Start(<-chan struct{})
+	HasSynced() bool
+
+	// Modified returns the timestamp of the most recent changes to services.
+	Modified() int64
+}
+
+type dnsControl struct {
+	// modified tracks timestamp of the most recent changes
+	modified  atomic.Int64
+	hasSynced atomic.Bool
+
+	svcController cache.Controller
+	epController  cache.Controller
+	nsController  cache.Controller
+
+	svcLister cache.Indexer
+	epLister  cache.Indexer
+	nsLister  cache.Store
+}
+
+// newdnsController creates a controller.
+func newdnsController(ctx context.Context, kubeClient kubernetes.Interface) *dnsControl {
+	dns := dnsControl{}
+
+	dns.svcLister, dns.svcController = object.NewIndexerInformer(
+		&cache.ListWatch{
+			ListFunc:  serviceListFunc(ctx, kubeClient, api.NamespaceAll),
+			WatchFunc: serviceWatchFunc(ctx, kubeClient, api.NamespaceAll),
+		},
+		&api.Service{},
+		&dns,
+		cache.Indexers{svcIPIndex: svcIPIndexFunc},
+		object.DefaultProcessor(object.ToService),
+	)
+
+	dns.epLister, dns.epController = object.NewIndexerInformer(
+		&cache.ListWatch{
+			ListFunc:  endpointSliceListFunc(ctx, kubeClient, api.NamespaceAll),
+			WatchFunc: endpointSliceWatchFunc(ctx, kubeClient, api.NamespaceAll),
+		},
+		&discovery.EndpointSlice{},
+		&dns,
+		cache.Indexers{epNameNamespaceIndex: epNameNamespaceIndexFunc, epIPIndex: epIPIndexFunc},
+		object.DefaultProcessor(object.EndpointSliceToEndpoints),
+	)
+
+	dns.nsLister, dns.nsController = object.NewIndexerInformer(
+		&cache.ListWatch{
+			ListFunc:  namespaceListFunc(ctx, kubeClient),
+			WatchFunc: namespaceWatchFunc(ctx, kubeClient),
+		},
+		&api.Namespace{},
+		&dns,
+		cache.Indexers{},
+		object.DefaultProcessor(object.ToNamespace),
+	)
+
+	return &dns
+}
+
+func svcIPIndexFunc(obj interface{}) ([]string, error) {
+	svc, ok := obj.(*object.Service)
+	if !ok {
+		return nil, errObj
+	}
+	idx := make([]string, len(svc.ClusterIPs))
+	copy(idx, svc.ClusterIPs)
+	return idx, nil
+}
+
+func epNameNamespaceIndexFunc(obj interface{}) ([]string, error) {
+	s, ok := obj.(*object.Endpoints)
+	if !ok {
+		return nil, errObj
+	}
+	return []string{s.Index}, nil
+}
+
+func epIPIndexFunc(obj interface{}) ([]string, error) {
+	ep, ok := obj.(*object.Endpoints)
+	if !ok {
+		return nil, errObj
+	}
+	idx := make([]string, len(ep.Addresses))
+	for i, addr := range ep.Addresses {
+		idx[i] = addr.IP
+	}
+	return idx, nil
+}
+
+func serviceListFunc(ctx context.Context, c kubernetes.Interface, ns string) func(meta.ListOptions) (runtime.Object, error) {
+	return func(opts meta.ListOptions) (runtime.Object, error) {
+		return c.CoreV1().Services(ns).List(ctx, opts)
+	}
+}
+
+func endpointSliceListFunc(ctx context.Context, c kubernetes.Interface, ns string) func(meta.ListOptions) (runtime.Object, error) {
+	return func(opts meta.ListOptions) (runtime.Object, error) {
+		opts.LabelSelector = epLabelSelector
+		return c.DiscoveryV1().EndpointSlices(ns).List(ctx, opts)
+	}
+}
+
+func namespaceListFunc(ctx context.Context, c kubernetes.Interface) func(meta.ListOptions) (runtime.Object, error) {
+	return func(opts meta.ListOptions) (runtime.Object, error) {
+		return c.CoreV1().Namespaces().List(ctx, opts)
+	}
+}
+
+func serviceWatchFunc(ctx context.Context, c kubernetes.Interface, ns string) func(options meta.ListOptions) (watch.Interface, error) {
+	return func(options meta.ListOptions) (watch.Interface, error) {
+		return c.CoreV1().Services(ns).Watch(ctx, options)
+	}
+}
+
+func endpointSliceWatchFunc(ctx context.Context, c kubernetes.Interface, ns string) func(options meta.ListOptions) (watch.Interface, error) {
+	return func(options meta.ListOptions) (watch.Interface, error) {
+		options.LabelSelector = epLabelSelector
+		return c.DiscoveryV1().EndpointSlices(ns).Watch(ctx, options)
+	}
+}
+
+func namespaceWatchFunc(ctx context.Context, c kubernetes.Interface) func(options meta.ListOptions) (watch.Interface, error) {
+	return func(options meta.ListOptions) (watch.Interface, error) {
+		return c.CoreV1().Namespaces().Watch(ctx, options)
+	}
+}
+
+// Start starts the controller.
+func (dns *dnsControl) Start(stopCh <-chan struct{}) {
+	go dns.svcController.Run(stopCh)
+	go dns.epController.Run(stopCh)
+	go dns.nsController.Run(stopCh)
+}
+
+// HasSynced returns true if the initial data has been
+// completely loaded into memory.
+func (dns *dnsControl) HasSynced() bool {
+	if dns.hasSynced.Load() {
+		return true
+	}
+	a := dns.svcController.HasSynced()
+	b := dns.epController.HasSynced()
+	c := dns.nsController.HasSynced()
+	if a && b && c {
+		dns.hasSynced.Store(true)
+		return true
+	}
+	return false
+}
+
+func (dns *dnsControl) GetSvc(key string) *object.Service {
+	o, exists, err := dns.svcLister.GetByKey(key)
+	if err != nil || !exists {
+		return nil
+	}
+	s, ok := o.(*object.Service)
+	if ok {
+		return s
+	}
+	return nil
+}
+
+func (dns *dnsControl) SvcIndexReverse(ip string) (svcs []*object.Service) {
+	os, err := dns.svcLister.ByIndex(svcIPIndex, ip)
+	if err != nil {
+		return nil
+	}
+	svcs = make([]*object.Service, 0, len(os))
+	for _, o := range os {
+		s, ok := o.(*object.Service)
+		if ok {
+			svcs = append(svcs, s)
+		}
+	}
+	return svcs
+}
+
+func (dns *dnsControl) EpIndex(idx string) (ep []*object.Endpoints) {
+	os, err := dns.epLister.ByIndex(epNameNamespaceIndex, idx)
+	if err != nil {
+		return nil
+	}
+	ep = make([]*object.Endpoints, 0, len(os))
+	for _, o := range os {
+		e, ok := o.(*object.Endpoints)
+		if ok {
+			ep = append(ep, e)
+		}
+	}
+	return ep
+}
+
+func (dns *dnsControl) EpIndexReverse(ip string) (ep []*object.Endpoints) {
+	os, err := dns.epLister.ByIndex(epIPIndex, ip)
+	if err != nil {
+		return nil
+	}
+	ep = make([]*object.Endpoints, 0, len(os))
+	for _, o := range os {
+		e, ok := o.(*object.Endpoints)
+		if ok {
+			ep = append(ep, e)
+		}
+	}
+	return ep
+}
+
+// NamespaceExists returns true if a namespace with this name exists.
+func (dns *dnsControl) NamespaceExists(name string) bool {
+	_, exists, _ := dns.nsLister.GetByKey(name)
+	return exists
+}
+
+func (dns *dnsControl) OnAdd(obj interface{}, isInInitialList bool) {
+	dns.updateModified()
+	switch obj := obj.(type) {
+	case *object.Endpoints:
+		// Don't record latency during initial sync, because measuring latency only
+		// makes sense for changes that happen while the service is running.
+		if !isInInitialList {
+			recordDNSProgrammingLatency(obj.LastChangeTriggerTime)
+		}
+	}
+}
+
+func (dns *dnsControl) OnDelete(obj interface{}) {
+	dns.updateModified()
+	// Note: We cannot record programming latency on deletes, because the trigger
+	// time annotation is not updated when the object is deleted.
+}
+
+func (dns *dnsControl) OnUpdate(oldObj, newObj interface{}) {
+	// If both objects have the same resource version, they are identical.
+	if oldObj.(meta.Object).GetResourceVersion() == newObj.(meta.Object).GetResourceVersion() {
+		return
+	}
+
+	switch newObj := newObj.(type) {
+	case *object.Service:
+		if object.ServiceModified(oldObj.(*object.Service), newObj) {
+			dns.updateModified()
+		}
+	case *object.Endpoints:
+		oldObj := oldObj.(*object.Endpoints)
+		if object.EndpointsModified(oldObj, newObj) {
+			dns.updateModified()
+			// If the trigger time has not changed, the process that last updated the
+			// object did not update the trigger time, so we can't know the latency.
+			if oldObj.LastChangeTriggerTime != newObj.LastChangeTriggerTime {
+				recordDNSProgrammingLatency(newObj.LastChangeTriggerTime)
+			}
+		}
+	}
+}
+
+func (dns *dnsControl) Modified() int64 {
+	return dns.modified.Load()
+}
+
+// updateModified set dns.modified to the current time.
+func (dns *dnsControl) updateModified() {
+	unix := time.Now().Unix()
+	dns.modified.Store(unix)
+}
+
+var errObj = errors.New("obj was not of the correct type")
diff --git a/osbase/net/dns/kubernetes/handler.go b/osbase/net/dns/kubernetes/handler.go
new file mode 100644
index 0000000..e6adf84
--- /dev/null
+++ b/osbase/net/dns/kubernetes/handler.go
@@ -0,0 +1,421 @@
+package kubernetes
+
+import (
+	"math/rand/v2"
+	"net"
+	"net/netip"
+
+	"github.com/miekg/dns"
+
+	netDNS "source.monogon.dev/osbase/net/dns"
+	"source.monogon.dev/osbase/net/dns/kubernetes/object"
+)
+
+const (
+	// DNSSchemaVersion is the schema version: https://github.com/kubernetes/dns/blob/master/docs/specification.md
+	DNSSchemaVersion = "1.1.0"
+	// defaultTTL to apply to all answers.
+	defaultTTL = 5
+)
+
+func (k *Kubernetes) HandleDNS(r *netDNS.Request) {
+	if netDNS.IsSubDomain(k.clusterDomain, r.QnameCanonical) {
+		r.SetAuthoritative()
+
+		subdomain := r.QnameCanonical[:len(r.QnameCanonical)-len(k.clusterDomain)]
+		subdomain, last := netDNS.SplitLastLabel(subdomain)
+		if last == "svc" {
+			k.handleService(r, subdomain)
+		} else if last == "" {
+			if r.Qtype == dns.TypeSOA || r.Qtype == dns.TypeANY {
+				r.Reply.Answer = append(r.Reply.Answer, k.makeSOA(r.Qname))
+			}
+			if r.Qtype == dns.TypeNS || r.Qtype == dns.TypeANY {
+				r.Reply.Answer = append(r.Reply.Answer, k.makeNS(r.Qname))
+			}
+		} else if last == "dns-version" && subdomain == "" {
+			if r.Qtype == dns.TypeTXT || r.Qtype == dns.TypeANY {
+				rr := new(dns.TXT)
+				rr.Hdr = dns.RR_Header{Name: r.Qname, Rrtype: dns.TypeTXT, Class: dns.ClassINET, Ttl: defaultTTL}
+				rr.Txt = []string{DNSSchemaVersion}
+				r.Reply.Answer = append(r.Reply.Answer, rr)
+			}
+		} else if last == "dns" && (subdomain == "" || subdomain == "ns.") {
+			// Name exists but has no records.
+		} else {
+			r.Reply.Rcode = dns.RcodeNameError
+		}
+
+		if r.Handled {
+			return
+		}
+		if len(r.Reply.Answer) == 0 {
+			zone := r.Qname[len(r.Qname)-len(k.clusterDomain):]
+			r.Reply.Ns = []dns.RR{k.makeSOA(zone)}
+		}
+		r.SendReply()
+		return
+	}
+
+	reverseIP, reverseBits, extra := netDNS.ParseReverse(r.QnameCanonical)
+	if reverseIP.IsValid() {
+		for _, ipRange := range k.ipRanges {
+			if !ipRange.Contains(reverseIP) || reverseBits < ipRange.Bits() {
+				continue
+			}
+
+			r.SetAuthoritative()
+
+			zoneBits := 0
+			if reverseIP.BitLen() == 32 {
+				zoneBits = (ipRange.Bits() + 7) & ^7
+			} else {
+				zoneBits = (ipRange.Bits() + 3) & ^3
+			}
+
+			if extra {
+				// Name with extra labels does not exist.
+				r.Reply.Rcode = dns.RcodeNameError
+			} else {
+				if reverseBits == reverseIP.BitLen() {
+					k.handleReverse(r, reverseIP)
+				}
+				if reverseBits == zoneBits {
+					if r.Qtype == dns.TypeSOA || r.Qtype == dns.TypeANY {
+						r.Reply.Answer = append(r.Reply.Answer, k.makeSOA(r.Qname))
+					}
+					if r.Qtype == dns.TypeNS || r.Qtype == dns.TypeANY {
+						r.Reply.Answer = append(r.Reply.Answer, k.makeNS(r.Qname))
+					}
+				}
+			}
+
+			if len(r.Reply.Answer) == 0 {
+				zoneDots := 0
+				if reverseIP.BitLen() == 32 {
+					zoneDots = 3 + zoneBits/8
+				} else {
+					zoneDots = 3 + zoneBits/4
+				}
+				zoneStart := len(r.Qname)
+				for zoneStart > 0 {
+					if r.Qname[zoneStart-1] == '.' {
+						zoneDots--
+						if zoneDots == 0 {
+							break
+						}
+					}
+					zoneStart--
+				}
+				zone := r.Qname[zoneStart:]
+				r.Reply.Ns = []dns.RR{k.makeSOA(zone)}
+			}
+			r.SendReply()
+			return
+		}
+	}
+}
+
+func (k *Kubernetes) handleService(r *netDNS.Request, subdomain string) {
+	if subdomain == "" {
+		// Name exists but has no records.
+		return
+	}
+
+	rest, namespace := netDNS.SplitLastLabel(subdomain)
+	if rest == "" {
+		// Name exists if the namespace exists, and has no records.
+		if !k.apiConn.NamespaceExists(namespace) {
+			k.notFound(r)
+		}
+		return
+	}
+
+	serviceSub, _ := netDNS.SplitLastLabel(rest)
+	rest, hostnameOrProto := netDNS.SplitLastLabel(serviceSub)
+
+	var proto string
+	var portName string
+	var hostname string
+	switch hostnameOrProto {
+	case "_tcp", "_udp", "_sctp":
+		proto = hostnameOrProto[1:]
+		rest, portName = netDNS.SplitLastLabel(rest)
+		if len(portName) >= 2 && portName[0] == '_' {
+			portName = portName[1:]
+		} else if portName != "" {
+			r.Reply.Rcode = dns.RcodeNameError
+			return
+		}
+		// If portName is empty, the name exists if the parent exists,
+		// but has no records.
+	default:
+		hostname = hostnameOrProto
+	}
+
+	if rest != "" {
+		// The query name has too many labels.
+		r.Reply.Rcode = dns.RcodeNameError
+		return
+	}
+
+	// serviceKey is "<service>.<ns>"
+	serviceKey := subdomain[len(serviceSub) : len(subdomain)-1]
+	service := k.apiConn.GetSvc(serviceKey)
+	if service == nil {
+		k.notFound(r)
+		return
+	}
+
+	// External service
+	if service.ExternalName != "" {
+		if serviceSub != "" {
+			// External services don't have subdomains.
+			r.Reply.Rcode = dns.RcodeNameError
+			return
+		}
+		if service.ExternalName == object.ExternalNameInvalid {
+			// The service has an invalid ExternalName, return an error.
+			r.AddExtendedError(dns.ExtendedErrorCodeInvalidData, "Kubernetes service has invalid externalName")
+			r.Reply.Rcode = dns.RcodeServerFailure
+			return
+		}
+		// We already ensure that ExternalName is valid and fully qualified
+		// when constructing the object.Service.
+		r.AddCNAME(service.ExternalName, defaultTTL)
+		return
+	}
+
+	// Headless service.
+	if service.Headless {
+		found := false
+		haveIP := make(map[string]struct{})
+		haveSRV := make(map[srvItem]struct{})
+		existingAnswer := len(r.Reply.Answer)
+		existingExtra := len(r.Reply.Extra)
+		for _, ep := range k.apiConn.EpIndex(serviceKey) {
+			if portName != "" {
+				// _<port>._<proto>.<service>.<ns>.svc.
+				var portNumber uint16
+				for _, p := range ep.Ports {
+					if p.Name == portName && p.Protocol == proto {
+						portNumber = p.Port
+						break
+					}
+				}
+				if portNumber == 0 {
+					continue
+				}
+				for _, addr := range ep.Addresses {
+					found = true
+					if r.Qtype == dns.TypeSRV || r.Qtype == dns.TypeANY {
+						targetName := addr.Hostname + r.Qname[len(serviceSub)-1:]
+						if !isDuplicateSRV(haveSRV, addr.Hostname, "", portNumber) {
+							addSRV(r, portNumber, targetName)
+						}
+						if !isDuplicateSRV(haveSRV, addr.Hostname, addr.IP, 0) {
+							addAddrExtra(r, targetName, net.IP(addr.IP))
+						}
+					}
+				}
+			} else {
+				// <service>.<ns>.svc. or <hostname>.<service>.<ns>.svc.
+				for _, addr := range ep.Addresses {
+					if hostname != "" && hostname != addr.Hostname {
+						continue
+					}
+					found = true
+					if proto != "" {
+						// _<proto>.<service>.<ns>.svc. has no records
+						// and exists if its parent exists.
+						break
+					}
+					if _, ok := haveIP[addr.IP]; !ok {
+						haveIP[addr.IP] = struct{}{}
+						addAddr(r, net.IP(addr.IP))
+					}
+				}
+			}
+		}
+		shuffleRRs(r.Reply.Answer[existingAnswer:])
+		shuffleRRs(r.Reply.Extra[existingExtra:])
+		if !found {
+			k.notFound(r)
+		}
+		return
+	}
+
+	if hostname != "" {
+		// Non-headless services don't have hostname records.
+		r.Reply.Rcode = dns.RcodeNameError
+		return
+	}
+
+	// ClusterIP service
+	if proto == "" {
+		// <service>.<ns>.svc. for ClusterIP service.
+		for _, ip := range service.ClusterIPs {
+			addAddr(r, net.IP(ip))
+		}
+		// The specification does not define what to return if the service has
+		// no (valid) clusterIP. We return an empty response with no error.
+		return
+	}
+
+	if portName == "" {
+		// _<proto>.<service>.<ns>.svc. exists but has no records.
+		return
+	}
+
+	// _<port>._<proto>.<service>.<ns>.svc. for ClusterIP service.
+	var portNumber uint16
+	for _, p := range service.Ports {
+		if p.Name == portName && p.Protocol == proto {
+			portNumber = p.Port
+			break
+		}
+	}
+	if portNumber == 0 {
+		r.Reply.Rcode = dns.RcodeNameError
+		return
+	}
+	if r.Qtype == dns.TypeSRV || r.Qtype == dns.TypeANY {
+		targetName := r.Qname[len(serviceSub):]
+		addSRV(r, portNumber, targetName)
+		for _, ip := range service.ClusterIPs {
+			addAddrExtra(r, targetName, net.IP(ip))
+		}
+	}
+}
+
+func (k *Kubernetes) handleReverse(r *netDNS.Request, ip netip.Addr) {
+	stringIP := string(ip.AsSlice())
+	found := false
+	for _, service := range k.apiConn.SvcIndexReverse(stringIP) {
+		found = true
+		if r.Qtype == dns.TypePTR || r.Qtype == dns.TypeANY {
+			rr := new(dns.PTR)
+			rr.Hdr = dns.RR_Header{Name: r.Qname, Rrtype: dns.TypePTR, Class: dns.ClassINET, Ttl: defaultTTL}
+			rr.Ptr = service.Name + "." + service.Namespace + ".svc." + k.clusterDomain
+			r.Reply.Answer = append(r.Reply.Answer, rr)
+		}
+	}
+	haveName := make(map[string]struct{})
+	for _, ep := range k.apiConn.EpIndexReverse(stringIP) {
+		for _, addr := range ep.Addresses {
+			if addr.IP == stringIP {
+				found = true
+				if r.Qtype == dns.TypePTR || r.Qtype == dns.TypeANY {
+					ptr := addr.Hostname + "." + ep.Index + ".svc." + k.clusterDomain
+					if _, ok := haveName[ptr]; ok {
+						continue
+					}
+					haveName[ptr] = struct{}{}
+					rr := new(dns.PTR)
+					rr.Hdr = dns.RR_Header{Name: r.Qname, Rrtype: dns.TypePTR, Class: dns.ClassINET, Ttl: defaultTTL}
+					rr.Ptr = ptr
+					r.Reply.Answer = append(r.Reply.Answer, rr)
+				}
+			}
+		}
+	}
+	if !found {
+		k.notFound(r)
+	}
+}
+
+func (k *Kubernetes) makeSOA(zone string) *dns.SOA {
+	header := dns.RR_Header{Name: zone, Rrtype: dns.TypeSOA, Class: dns.ClassINET, Ttl: defaultTTL}
+	return &dns.SOA{
+		Hdr:     header,
+		Mbox:    "nobody.invalid.",
+		Ns:      k.nsDomain,
+		Serial:  uint32(k.apiConn.Modified()),
+		Refresh: 7200,
+		Retry:   1800,
+		Expire:  86400,
+		Minttl:  defaultTTL,
+	}
+}
+
+func (k *Kubernetes) makeNS(zone string) *dns.NS {
+	rr := new(dns.NS)
+	rr.Hdr = dns.RR_Header{Name: zone, Rrtype: dns.TypeNS, Class: dns.ClassINET, Ttl: defaultTTL}
+	rr.Ns = k.nsDomain
+	return rr
+}
+
+func addAddr(r *netDNS.Request, ip net.IP) {
+	if len(ip) == net.IPv4len && (r.Qtype == dns.TypeA || r.Qtype == dns.TypeANY) {
+		rr := new(dns.A)
+		rr.Hdr = dns.RR_Header{Name: r.Qname, Rrtype: dns.TypeA, Class: dns.ClassINET, Ttl: defaultTTL}
+		rr.A = ip
+		r.Reply.Answer = append(r.Reply.Answer, rr)
+	}
+	if len(ip) == net.IPv6len && (r.Qtype == dns.TypeAAAA || r.Qtype == dns.TypeANY) {
+		rr := new(dns.AAAA)
+		rr.Hdr = dns.RR_Header{Name: r.Qname, Rrtype: dns.TypeAAAA, Class: dns.ClassINET, Ttl: defaultTTL}
+		rr.AAAA = ip
+		r.Reply.Answer = append(r.Reply.Answer, rr)
+	}
+}
+
+func addAddrExtra(r *netDNS.Request, name string, ip net.IP) {
+	if len(ip) == net.IPv4len {
+		rr := new(dns.A)
+		rr.Hdr = dns.RR_Header{Name: name, Rrtype: dns.TypeA, Class: dns.ClassINET, Ttl: defaultTTL}
+		rr.A = ip
+		r.Reply.Extra = append(r.Reply.Extra, rr)
+	}
+	if len(ip) == net.IPv6len {
+		rr := new(dns.AAAA)
+		rr.Hdr = dns.RR_Header{Name: name, Rrtype: dns.TypeAAAA, Class: dns.ClassINET, Ttl: defaultTTL}
+		rr.AAAA = ip
+		r.Reply.Extra = append(r.Reply.Extra, rr)
+	}
+}
+
+func addSRV(r *netDNS.Request, portNumber uint16, targetName string) {
+	rr := new(dns.SRV)
+	rr.Hdr = dns.RR_Header{Name: r.Qname, Rrtype: dns.TypeSRV, Class: dns.ClassINET, Ttl: defaultTTL}
+	rr.Priority = 0
+	rr.Weight = 0
+	rr.Port = portNumber
+	rr.Target = targetName
+	r.Reply.Answer = append(r.Reply.Answer, rr)
+}
+
+// notFound should be called if a name was not found, but could exist
+// if there are Kubernetes object that are not yet available locally.
+func (k *Kubernetes) notFound(r *netDNS.Request) {
+	if !k.apiConn.HasSynced() {
+		// We don't know if the name exists or not, so return an error.
+		r.AddExtendedError(dns.ExtendedErrorCodeNotReady, "Kubernetes objects not yet synced")
+		r.Reply.Rcode = dns.RcodeServerFailure
+	} else {
+		r.Reply.Rcode = dns.RcodeNameError
+	}
+}
+
+type srvItem struct {
+	name string
+	addr string
+	port uint16
+}
+
+// isDuplicateSRV returns true if the (name, addr, port) combination already
+// exists in m, and adds it to m if not.
+func isDuplicateSRV(m map[srvItem]struct{}, name, addr string, port uint16) bool {
+	_, ok := m[srvItem{name, addr, port}]
+	if !ok {
+		m[srvItem{name, addr, port}] = struct{}{}
+	}
+	return ok
+}
+
+// shuffleRRs shuffles a slice of RRs for some load balancing.
+func shuffleRRs(rrs []dns.RR) {
+	rand.Shuffle(len(rrs), func(i, j int) {
+		rrs[i], rrs[j] = rrs[j], rrs[i]
+	})
+}
diff --git a/osbase/net/dns/kubernetes/handler_test.go b/osbase/net/dns/kubernetes/handler_test.go
new file mode 100644
index 0000000..76bd32d
--- /dev/null
+++ b/osbase/net/dns/kubernetes/handler_test.go
@@ -0,0 +1,783 @@
+package kubernetes
+
+import (
+	"context"
+	"fmt"
+	"net/netip"
+	"slices"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/miekg/dns"
+	api "k8s.io/api/core/v1"
+	discovery "k8s.io/api/discovery/v1"
+	meta "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/util/intstr"
+	"k8s.io/client-go/kubernetes/fake"
+	"k8s.io/utils/ptr"
+
+	netDNS "source.monogon.dev/osbase/net/dns"
+)
+
+const testdataClusterDomain = "cluster.local"
+
+var testdataIPRanges = []string{
+	// service IP
+	"10.0.0.1/16",
+	"1234:abcd::/64",
+	// pod IP
+	"172.32.0.0/11",
+	"170::/14",
+}
+
+var testdataNamespaces = []string{"testns"}
+
+var testdataServices = []*api.Service{
+	{
+		ObjectMeta: meta.ObjectMeta{
+			Name:      "svc-clusterip",
+			Namespace: "testns",
+		},
+		Spec: api.ServiceSpec{
+			Type:       api.ServiceTypeClusterIP,
+			ClusterIPs: []string{"10.0.0.10"},
+			Ports: []api.ServicePort{
+				{Name: "http", Protocol: api.ProtocolTCP, Port: 80, TargetPort: intstr.FromInt32(82)},
+			},
+		},
+	},
+	{
+		ObjectMeta: meta.ObjectMeta{
+			Name:      "svc-dualstack",
+			Namespace: "testns",
+		},
+		Spec: api.ServiceSpec{
+			Type:       api.ServiceTypeClusterIP,
+			ClusterIPs: []string{"10.0.0.11", "1234:abcd::11"},
+			Ports: []api.ServicePort{
+				{Name: "http", Protocol: api.ProtocolTCP, Port: 80},
+				{Name: "dns", Protocol: api.ProtocolUDP, Port: 53},
+			},
+		},
+	},
+	{
+		ObjectMeta: meta.ObjectMeta{
+			Name:      "svc-headless",
+			Namespace: "testns",
+		},
+		Spec: api.ServiceSpec{
+			Type:       api.ServiceTypeClusterIP,
+			ClusterIP:  api.ClusterIPNone,
+			ClusterIPs: []string{api.ClusterIPNone},
+			Ports: []api.ServicePort{
+				{Name: "http", Protocol: api.ProtocolTCP, Port: 80, TargetPort: intstr.FromString("http")},
+			},
+		},
+	},
+	{
+		ObjectMeta: meta.ObjectMeta{
+			Name:      "svc-headless-notready",
+			Namespace: "testns",
+		},
+		Spec: api.ServiceSpec{
+			Type:       api.ServiceTypeClusterIP,
+			ClusterIP:  api.ClusterIPNone,
+			ClusterIPs: []string{api.ClusterIPNone},
+			Ports: []api.ServicePort{
+				{Name: "http", Protocol: api.ProtocolTCP, Port: 80, TargetPort: intstr.FromString("http")},
+			},
+		},
+	},
+	{
+		ObjectMeta: meta.ObjectMeta{
+			Name:      "svc-external",
+			Namespace: "testns",
+		},
+		Spec: api.ServiceSpec{
+			Type:         api.ServiceTypeExternalName,
+			ExternalName: "external.example.com",
+		},
+	},
+}
+
+var testdataEndpointSlices = []*discovery.EndpointSlice{
+	{
+		ObjectMeta: meta.ObjectMeta{
+			Name:      "svc-clusterip-slice",
+			Namespace: "testns",
+			Labels:    map[string]string{discovery.LabelServiceName: "svc-clusterip"},
+		},
+		Endpoints: []discovery.Endpoint{
+			{Addresses: []string{"172.45.0.1"}},
+		},
+	},
+	{
+		ObjectMeta: meta.ObjectMeta{
+			Name:      "svc-headless-slice1",
+			Namespace: "testns",
+			Labels: map[string]string{
+				discovery.LabelServiceName: "svc-headless",
+				api.IsHeadlessService:      "",
+			},
+		},
+		Endpoints: []discovery.Endpoint{
+			{
+				Addresses: []string{"172.45.0.2"},
+			},
+			{
+				Addresses: []string{"172.45.0.2"},
+			},
+			{
+				Hostname:   ptr.To("pod3"),
+				Addresses:  []string{"172.45.0.3"},
+				Conditions: discovery.EndpointConditions{Ready: ptr.To(true)},
+			},
+			{
+				Addresses:  []string{"172.45.0.4"},
+				Conditions: discovery.EndpointConditions{Ready: ptr.To(false)},
+			},
+			{
+				Hostname:  ptr.To("pod5"),
+				Addresses: []string{"172.45.0.5", "172.45.0.2"},
+			},
+		},
+		Ports: []discovery.EndpointPort{
+			{Name: ptr.To("http"), Port: ptr.To(int32(8000)), Protocol: ptr.To(api.ProtocolTCP)},
+		},
+	},
+	{
+		ObjectMeta: meta.ObjectMeta{
+			Name:      "svc-headless-slice2",
+			Namespace: "testns",
+			Labels: map[string]string{
+				discovery.LabelServiceName: "svc-headless",
+				api.IsHeadlessService:      "",
+			},
+		},
+		Endpoints: []discovery.Endpoint{
+			{
+				Hostname:   ptr.To("pod3"),
+				Addresses:  []string{"172::3"},
+				Conditions: discovery.EndpointConditions{Ready: ptr.To(false)},
+			},
+			{
+				Hostname:  ptr.To("pod5"),
+				Addresses: []string{"172::5"},
+			},
+			{
+				Addresses: []string{"172::7"},
+			},
+		},
+		Ports: []discovery.EndpointPort{
+			{Name: ptr.To("http"), Port: ptr.To(int32(8001)), Protocol: ptr.To(api.ProtocolTCP)},
+		},
+	},
+	{
+		ObjectMeta: meta.ObjectMeta{
+			Name:      "svc-headless-notready-slice1",
+			Namespace: "testns",
+			Labels: map[string]string{
+				discovery.LabelServiceName: "svc-headless-notready",
+				api.IsHeadlessService:      "",
+			},
+		},
+		Endpoints: []discovery.Endpoint{
+			{
+				Addresses:  []string{"172.45.0.20"},
+				Conditions: discovery.EndpointConditions{Ready: ptr.To(false)},
+			},
+			{
+				Hostname:   ptr.To("pod21"),
+				Addresses:  []string{"172.45.0.21"},
+				Conditions: discovery.EndpointConditions{Ready: ptr.To(false)},
+			},
+		},
+		Ports: []discovery.EndpointPort{
+			{Name: ptr.To("http"), Port: ptr.To(int32(8000)), Protocol: ptr.To(api.ProtocolTCP)},
+		},
+	},
+}
+
+// handlerTestcase contains a query name, and the expected records
+// under that name given the above test data.
+type handlerTestcase struct {
+	// Query name
+	qname string
+
+	// Expected reply
+
+	rcode         int
+	answer, extra []string
+	notHandled    bool
+	// zone is the zone that is expected in the NS SOA if the answer is empty.
+	// If zone is empty, defaults to "cluster.local."
+	zone string
+}
+
+// nameErrorIfSynced means name error if synced, else server failure.
+const nameErrorIfSynced = -1
+
+var handlerTestcases = []handlerTestcase{
+	// cluster domain root
+	{
+		qname: "cluster.local.",
+		answer: []string{
+			"cluster.local.	5	IN	SOA	ns.dns.cluster.local. nobody.invalid. 12345 7200 1800 86400 5",
+			"cluster.local.	5	IN	NS	ns.dns.cluster.local.",
+		},
+	},
+	{
+		qname: "example.cluster.local.",
+		rcode: dns.RcodeNameError,
+	},
+	// dns-version
+	{
+		qname: "dns-version.cluster.local.",
+		answer: []string{
+			`dns-version.cluster.local.	5	IN	TXT	"1.1.0"`,
+		},
+	},
+	{
+		qname: "example.dns-version.cluster.local.",
+		rcode: dns.RcodeNameError,
+	},
+	// ns.dns
+	{
+		qname: "dns.cluster.local.",
+	},
+	{
+		qname: "ns.dns.cluster.local.",
+	},
+	{
+		qname: "example.dns.cluster.local.",
+		rcode: dns.RcodeNameError,
+	},
+	// svc
+	{
+		qname: "svc.cluster.local.",
+	},
+	// namespace
+	{
+		qname: "testns.svc.cluster.local.",
+	},
+	{
+		qname: "inexistent-ns.svc.cluster.local.",
+		rcode: nameErrorIfSynced,
+	},
+	// cluster IP service
+	{
+		qname: "svc-clusterip.testns.svc.cluster.local.",
+		answer: []string{
+			"svc-clusterip.testns.svc.cluster.local.	5	IN	A	10.0.0.10",
+		},
+	},
+	{
+		qname: "_http._tcp.svc-clusterip.testns.svc.cluster.local.",
+		answer: []string{
+			"_http._tcp.svc-clusterip.testns.svc.cluster.local.	5	IN	SRV	0 0 80 svc-clusterip.testns.svc.cluster.local.",
+		},
+		extra: []string{
+			"svc-clusterip.testns.svc.cluster.local.	5	IN	A	10.0.0.10",
+		},
+	},
+	{
+		qname: "_udp.svc-clusterip.testns.svc.cluster.local.",
+	},
+	{
+		qname: "_http._udp.svc-clusterip.testns.svc.cluster.local.",
+		rcode: dns.RcodeNameError,
+	},
+	{
+		qname: "http._tcp.svc-clusterip.testns.svc.cluster.local.",
+		rcode: dns.RcodeNameError,
+	},
+	{
+		qname: "example._http._tcp.svc-clusterip.testns.svc.cluster.local.",
+		rcode: dns.RcodeNameError,
+	},
+	{
+		qname: "10.0.0.10.in-addr.arpa.",
+		answer: []string{
+			"10.0.0.10.in-addr.arpa.	5	IN	PTR	svc-clusterip.testns.svc.cluster.local.",
+		},
+		zone: "0.10.in-addr.arpa.",
+	},
+	{
+		qname: "172-45-0-1.svc-clusterip.testns.svc.cluster.local.",
+		rcode: dns.RcodeNameError,
+	},
+	{
+		qname: "1.0.45.172.in-addr.arpa.",
+		rcode: nameErrorIfSynced,
+		zone:  "45.172.in-addr.arpa.",
+	},
+	// dual stack cluster IP service
+	{
+		qname: "svc-dualstack.testns.svc.cluster.local.",
+		answer: []string{
+			"svc-dualstack.testns.svc.cluster.local.	5	IN	A	10.0.0.11",
+			"svc-dualstack.testns.svc.cluster.local.	5	IN	AAAA	1234:abcd::11",
+		},
+	},
+	{
+		qname: "_http._tcp.svc-dualstack.testns.svc.cluster.local.",
+		answer: []string{
+			"_http._tcp.svc-dualstack.testns.svc.cluster.local.	5	IN	SRV	0 0 80 svc-dualstack.testns.svc.cluster.local.",
+		},
+		extra: []string{
+			"svc-dualstack.testns.svc.cluster.local.	5	IN	A	10.0.0.11",
+			"svc-dualstack.testns.svc.cluster.local.	5	IN	AAAA	1234:abcd::11",
+		},
+	},
+	{
+		qname: "11.0.0.10.in-addr.arpa.",
+		answer: []string{
+			"11.0.0.10.in-addr.arpa.	5	IN	PTR	svc-dualstack.testns.svc.cluster.local.",
+		},
+		zone: "0.10.in-addr.arpa.",
+	},
+	{
+		qname: "1.1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.d.c.b.a.4.3.2.1.ip6.arpa.",
+		answer: []string{
+			"1.1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.d.c.b.a.4.3.2.1.ip6.arpa.	5	IN	PTR	svc-dualstack.testns.svc.cluster.local.",
+		},
+		zone: "0.0.0.0.0.0.0.0.d.c.b.a.4.3.2.1.ip6.arpa.",
+	},
+	// headless service
+	{
+		qname: "svc-headless.testns.svc.cluster.local.",
+		answer: []string{
+			"svc-headless.testns.svc.cluster.local.	5	IN	A	172.45.0.2",
+			"svc-headless.testns.svc.cluster.local.	5	IN	A	172.45.0.3",
+			"svc-headless.testns.svc.cluster.local.	5	IN	A	172.45.0.5",
+			"svc-headless.testns.svc.cluster.local.	5	IN	AAAA	172::5",
+			"svc-headless.testns.svc.cluster.local.	5	IN	AAAA	172::7",
+		},
+	},
+	{
+		qname: "_http._tcp.svc-headless.testns.svc.cluster.local.",
+		answer: []string{
+			"_http._tcp.svc-headless.testns.svc.cluster.local.	5	IN	SRV	0 0 8000 172-45-0-2.svc-headless.testns.svc.cluster.local.",
+			"_http._tcp.svc-headless.testns.svc.cluster.local.	5	IN	SRV	0 0 8000 pod3.svc-headless.testns.svc.cluster.local.",
+			"_http._tcp.svc-headless.testns.svc.cluster.local.	5	IN	SRV	0 0 8000 pod5.svc-headless.testns.svc.cluster.local.",
+			"_http._tcp.svc-headless.testns.svc.cluster.local.	5	IN	SRV	0 0 8001 pod5.svc-headless.testns.svc.cluster.local.",
+			"_http._tcp.svc-headless.testns.svc.cluster.local.	5	IN	SRV	0 0 8001 172--7.svc-headless.testns.svc.cluster.local.",
+		},
+		extra: []string{
+			"172-45-0-2.svc-headless.testns.svc.cluster.local.	5	IN	A	172.45.0.2",
+			"pod3.svc-headless.testns.svc.cluster.local.	5	IN	A	172.45.0.3",
+			"pod5.svc-headless.testns.svc.cluster.local.	5	IN	A	172.45.0.5",
+			"pod5.svc-headless.testns.svc.cluster.local.	5	IN	A	172.45.0.2",
+			"pod5.svc-headless.testns.svc.cluster.local.	5	IN	AAAA	172::5",
+			"172--7.svc-headless.testns.svc.cluster.local.	5	IN	AAAA	172::7",
+		},
+	},
+	{
+		qname: "_udp.svc-headless.testns.svc.cluster.local.",
+	},
+	{
+		qname: "_http._udp.svc-headless.testns.svc.cluster.local.",
+		rcode: nameErrorIfSynced,
+	},
+	{
+		qname: "http._tcp.svc-headless.testns.svc.cluster.local.",
+		rcode: dns.RcodeNameError,
+	},
+	{
+		qname: "_._udp.svc-headless.testns.svc.cluster.local.",
+		rcode: dns.RcodeNameError,
+	},
+	{
+		qname: "example._http._tcp.svc-headless.testns.svc.cluster.local.",
+		rcode: dns.RcodeNameError,
+	},
+	{
+		qname: "172-45-0-2.svc-headless.testns.svc.cluster.local.",
+		answer: []string{
+			"172-45-0-2.svc-headless.testns.svc.cluster.local.	5	IN	A	172.45.0.2",
+		},
+	},
+	{
+		qname: "pod5.svc-headless.testns.svc.cluster.local.",
+		answer: []string{
+			"pod5.svc-headless.testns.svc.cluster.local.	5	IN	A	172.45.0.5",
+			"pod5.svc-headless.testns.svc.cluster.local.	5	IN	A	172.45.0.2",
+			"pod5.svc-headless.testns.svc.cluster.local.	5	IN	AAAA	172::5",
+		},
+	},
+	{
+		qname: "example.pod5.svc-headless.testns.svc.cluster.local.",
+		rcode: dns.RcodeNameError,
+	},
+	{
+		qname: "172-45-0-5.svc-headless.testns.svc.cluster.local.",
+		rcode: nameErrorIfSynced,
+	},
+	{
+		qname: "2.0.45.172.in-addr.arpa.",
+		answer: []string{
+			"2.0.45.172.in-addr.arpa.	5	IN	PTR	172-45-0-2.svc-headless.testns.svc.cluster.local.",
+			"2.0.45.172.in-addr.arpa.	5	IN	PTR	pod5.svc-headless.testns.svc.cluster.local.",
+		},
+		zone: "45.172.in-addr.arpa.",
+	},
+	{
+		qname: "5.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.2.7.1.0.ip6.arpa.",
+		answer: []string{
+			"5.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.2.7.1.0.ip6.arpa.	5	IN	PTR	pod5.svc-headless.testns.svc.cluster.local.",
+		},
+		zone: "2.7.1.0.ip6.arpa.",
+	},
+	// not ready headless service
+	{
+		qname: "svc-headless-notready.testns.svc.cluster.local.",
+		rcode: nameErrorIfSynced,
+	},
+	{
+		qname: "_tcp.svc-headless-notready.testns.svc.cluster.local.",
+		rcode: nameErrorIfSynced,
+	},
+	{
+		qname: "_http._tcp.svc-headless-notready.testns.svc.cluster.local.",
+		rcode: nameErrorIfSynced,
+	},
+	{
+		qname: "pod21.svc-headless-notready.testns.svc.cluster.local.",
+		rcode: nameErrorIfSynced,
+	},
+	{
+		qname: "21.0.45.172.in-addr.arpa.",
+		rcode: nameErrorIfSynced,
+		zone:  "45.172.in-addr.arpa.",
+	},
+	// external service
+	{
+		qname: "svc-external.testns.svc.cluster.local.",
+		answer: []string{
+			"svc-external.testns.svc.cluster.local.	5	IN	CNAME	external.example.com.",
+		},
+	},
+	{
+		qname: "_tcp.svc-external.testns.svc.cluster.local.",
+		rcode: dns.RcodeNameError,
+	},
+	{
+		qname: "_http._tcp.svc-external.testns.svc.cluster.local.",
+		rcode: dns.RcodeNameError,
+	},
+	{
+		qname: "pod.svc-external.testns.svc.cluster.local.",
+		rcode: dns.RcodeNameError,
+	},
+	// service does not exist
+	{
+		qname: "inexistent-svc.testns.svc.cluster.local.",
+		rcode: nameErrorIfSynced,
+	},
+	{
+		qname: "_tcp.inexistent-svc.testns.svc.cluster.local.",
+		rcode: nameErrorIfSynced,
+	},
+	{
+		qname: "_http._tcp.inexistent-svc.testns.svc.cluster.local.",
+		rcode: nameErrorIfSynced,
+	},
+	{
+		qname: "example._tcp.inexistent-svc.testns.svc.cluster.local.",
+		rcode: dns.RcodeNameError,
+	},
+	{
+		qname: "example._http._tcp.inexistent-svc.testns.svc.cluster.local.",
+		rcode: dns.RcodeNameError,
+	},
+	{
+		qname: "pod.inexistent-svc.testns.svc.cluster.local.",
+		rcode: nameErrorIfSynced,
+	},
+	{
+		qname: "example.pod.inexistent-svc.testns.svc.cluster.local.",
+		rcode: dns.RcodeNameError,
+	},
+	// names which do not exist but will get queried because of ndots=5
+	{
+		qname: "www.example.com.cluster.local.",
+		rcode: dns.RcodeNameError,
+	},
+	{
+		qname: "www.example.com.svc.cluster.local.",
+		rcode: nameErrorIfSynced,
+	},
+	{
+		qname: "www.example.com.testns.svc.cluster.local.",
+		rcode: dns.RcodeNameError,
+	},
+	// names which are not handled
+	{
+		qname:      "www.example.com.",
+		notHandled: true,
+	},
+	{
+		qname:      "12.0.31.172.in-addr.arpa.",
+		notHandled: true,
+	},
+	{
+		qname:      "5.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.4.7.1.0.ip6.arpa.",
+		notHandled: true,
+	},
+	{
+		qname:      "10.in-addr.arpa.",
+		notHandled: true,
+	},
+	{
+		qname:      "7.1.0.ip6.arpa.",
+		notHandled: true,
+	},
+	// reverse lookup zone
+	{
+		qname: "45.172.in-addr.arpa.",
+		answer: []string{
+			"45.172.in-addr.arpa.	5	IN	SOA	ns.dns.cluster.local. nobody.invalid. 12345 7200 1800 86400 5",
+			"45.172.in-addr.arpa.	5	IN	NS	ns.dns.cluster.local.",
+		},
+		zone: "45.172.in-addr.arpa.",
+	},
+	{
+		qname: "255.45.172.in-addr.arpa.",
+		zone:  "45.172.in-addr.arpa.",
+	},
+	{
+		qname: "02.0.45.172.in-addr.arpa.",
+		rcode: dns.RcodeNameError,
+		zone:  "45.172.in-addr.arpa.",
+	},
+	{
+		qname: "1.2.0.45.172.in-addr.arpa.",
+		rcode: dns.RcodeNameError,
+		zone:  "45.172.in-addr.arpa.",
+	},
+	{
+		qname: "2.7.1.0.ip6.arpa.",
+		answer: []string{
+			"2.7.1.0.ip6.arpa.	5	IN	SOA	ns.dns.cluster.local. nobody.invalid. 12345 7200 1800 86400 5",
+			"2.7.1.0.ip6.arpa.	5	IN	NS	ns.dns.cluster.local.",
+		},
+		zone: "2.7.1.0.ip6.arpa.",
+	},
+	{
+		qname: "a.2.7.1.0.ip6.arpa.",
+		zone:  "2.7.1.0.ip6.arpa.",
+	},
+	{
+		qname: "x.a.2.7.1.0.ip6.arpa.",
+		rcode: dns.RcodeNameError,
+		zone:  "2.7.1.0.ip6.arpa.",
+	},
+	// mixed case
+	{
+		qname: "SvC-cLUSteRIp.TesTNS.sVC.ClUSTer.locAL.",
+		answer: []string{
+			"SvC-cLUSteRIp.TesTNS.sVC.ClUSTer.locAL.	5	IN	A	10.0.0.10",
+		},
+		zone: "ClUSTer.locAL.",
+	},
+	{
+		qname: "_hTTp._tCp.SVc-hEADlEsS.teSTNs.SVC.ClUSTer.locAL.",
+		answer: []string{
+			"_hTTp._tCp.SVc-hEADlEsS.teSTNs.SVC.ClUSTer.locAL.	5	IN	SRV	0 0 8000 172-45-0-2.SVc-hEADlEsS.teSTNs.SVC.ClUSTer.locAL.",
+			"_hTTp._tCp.SVc-hEADlEsS.teSTNs.SVC.ClUSTer.locAL.	5	IN	SRV	0 0 8000 pod3.SVc-hEADlEsS.teSTNs.SVC.ClUSTer.locAL.",
+			"_hTTp._tCp.SVc-hEADlEsS.teSTNs.SVC.ClUSTer.locAL.	5	IN	SRV	0 0 8000 pod5.SVc-hEADlEsS.teSTNs.SVC.ClUSTer.locAL.",
+			"_hTTp._tCp.SVc-hEADlEsS.teSTNs.SVC.ClUSTer.locAL.	5	IN	SRV	0 0 8001 pod5.SVc-hEADlEsS.teSTNs.SVC.ClUSTer.locAL.",
+			"_hTTp._tCp.SVc-hEADlEsS.teSTNs.SVC.ClUSTer.locAL.	5	IN	SRV	0 0 8001 172--7.SVc-hEADlEsS.teSTNs.SVC.ClUSTer.locAL.",
+		},
+		extra: []string{
+			"172-45-0-2.SVc-hEADlEsS.teSTNs.SVC.ClUSTer.locAL.	5	IN	A	172.45.0.2",
+			"pod3.SVc-hEADlEsS.teSTNs.SVC.ClUSTer.locAL.	5	IN	A	172.45.0.3",
+			"pod5.SVc-hEADlEsS.teSTNs.SVC.ClUSTer.locAL.	5	IN	A	172.45.0.5",
+			"pod5.SVc-hEADlEsS.teSTNs.SVC.ClUSTer.locAL.	5	IN	A	172.45.0.2",
+			"pod5.SVc-hEADlEsS.teSTNs.SVC.ClUSTer.locAL.	5	IN	AAAA	172::5",
+			"172--7.SVc-hEADlEsS.teSTNs.SVC.ClUSTer.locAL.	5	IN	AAAA	172::7",
+		},
+		zone: "ClUSTer.locAL.",
+	},
+	{
+		qname: "1.1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.d.C.b.a.4.3.2.1.iP6.ARpa.",
+		answer: []string{
+			"1.1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.d.C.b.a.4.3.2.1.iP6.ARpa.	5	IN	PTR	svc-dualstack.testns.svc.cluster.local.",
+		},
+		zone: "0.0.0.0.0.0.0.0.d.C.b.a.4.3.2.1.iP6.ARpa.",
+	},
+}
+
+// TestHandler constructs a fake Kubernetes clientset containing the above
+// testdata, and then evaluates each test case in handlerTestcases.
+func TestHandler(t *testing.T) {
+	ctx := context.Background()
+	client := fake.NewSimpleClientset()
+
+	// Add resources
+	for _, name := range testdataNamespaces {
+		namespace := &api.Namespace{
+			ObjectMeta: meta.ObjectMeta{Name: name},
+		}
+		_, err := client.CoreV1().Namespaces().Create(ctx, namespace, meta.CreateOptions{})
+		if err != nil {
+			t.Fatal(err)
+		}
+	}
+	for _, service := range testdataServices {
+		_, err := client.CoreV1().Services(service.Namespace).Create(ctx, service, meta.CreateOptions{})
+		if err != nil {
+			t.Fatal(err)
+		}
+	}
+	for _, slice := range testdataEndpointSlices {
+		_, err := client.DiscoveryV1().EndpointSlices(slice.Namespace).Create(ctx, slice, meta.CreateOptions{})
+		if err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	// Create handler
+	var ipRanges []netip.Prefix
+	for _, ipRange := range testdataIPRanges {
+		ipRanges = append(ipRanges, netip.MustParsePrefix(ipRange))
+	}
+	handler := New(testdataClusterDomain, ipRanges)
+	handler.ClientSet = client
+
+	wrapper := &dnsControllerWrapper{dnsController: newdnsController(ctx, handler.ClientSet)}
+	handler.apiConn = wrapper
+
+	stopCh := make(chan struct{})
+	defer close(stopCh)
+	handler.apiConn.Start(stopCh)
+	for !wrapper.dnsController.HasSynced() {
+		time.Sleep(time.Millisecond)
+	}
+
+	for _, hasSynced := range []bool{true, false} {
+		wrapper.hasSynced = hasSynced
+		for _, testcase := range handlerTestcases {
+			if testcase.zone == "" {
+				testcase.zone = "cluster.local."
+			}
+			if testcase.rcode == nameErrorIfSynced {
+				if hasSynced {
+					testcase.rcode = dns.RcodeNameError
+				} else {
+					testcase.rcode = dns.RcodeServerFailure
+				}
+			}
+
+			qtypes := []uint16{
+				dns.TypeANY, dns.TypeA, dns.TypeAAAA, dns.TypeSRV, dns.TypeTXT,
+				dns.TypeNS, dns.TypeSOA, dns.TypePTR, dns.TypeMX, dns.TypeCNAME,
+			}
+			for _, qtype := range qtypes {
+				doHandlerTestcase(t, handler, testcase, qtype)
+			}
+		}
+	}
+
+	wrapper.hasSynced = false
+	testNotSyncedOpt(t, handler)
+}
+
+func doHandlerTestcase(t *testing.T, handler *Kubernetes, testcase handlerTestcase, qtype uint16) {
+	// Create request
+	req := netDNS.CreateTestRequest(testcase.qname, qtype, "udp")
+	req.Reply.RecursionDesired = false
+	req.Qopt = nil
+	req.Ropt = nil
+
+	handler.HandleDNS(req)
+
+	caseName := fmt.Sprintf("Query %s %s", testcase.qname, dns.TypeToString[qtype])
+	if !handler.apiConn.HasSynced() {
+		caseName += " not_synced"
+	}
+
+	if req.Handled != !testcase.notHandled {
+		t.Errorf("%s: Expected handled %v, got %v", caseName,
+			!testcase.notHandled, req.Handled,
+		)
+		return
+	}
+	if !req.Handled {
+		return
+	}
+
+	if req.Reply.Rcode != testcase.rcode {
+		t.Errorf("%s: Expected rcode %s, got %s", caseName,
+			dns.RcodeToString[testcase.rcode], dns.RcodeToString[req.Reply.Rcode],
+		)
+		return
+	}
+
+	// Create expected answer
+	var answer []string
+	for _, rr := range testcase.answer {
+		rrParsed, err := dns.NewRR(rr)
+		if err != nil {
+			t.Fatalf("Failed to parse DNS RR %q: %v", rr, err)
+		}
+		if qtype == dns.TypeANY || qtype == rrParsed.Header().Rrtype || rrParsed.Header().Rrtype == dns.TypeCNAME {
+			answer = append(answer, rr)
+		}
+	}
+	var extra []string
+	var ns []string
+	if len(answer) != 0 {
+		extra = testcase.extra
+	} else {
+		ns = []string{
+			testcase.zone + "	5	IN	SOA	ns.dns.cluster.local. nobody.invalid. 12345 7200 1800 86400 5",
+		}
+	}
+
+	checkReplySection(t, caseName, "answer", answer, req.Reply.Answer)
+	checkReplySection(t, caseName, "ns", ns, req.Reply.Ns)
+	checkReplySection(t, caseName, "extra", extra, req.Reply.Extra)
+}
+
+func checkReplySection(t *testing.T, caseName string, sectionName string, expected []string, got []dns.RR) {
+	slices.Sort(expected)
+	var gotStr []string
+	for _, rr := range got {
+		gotStr = append(gotStr, rr.String())
+	}
+	slices.Sort(gotStr)
+	if !slices.Equal(expected, gotStr) {
+		t.Errorf("%s: Expected %s:\n%s\nGot:\n%v", caseName, sectionName,
+			strings.Join(expected, "\n"), strings.Join(gotStr, "\n"))
+	}
+}
+
+// testNotSyncedOpt tests that we get the Not Ready extended error
+// when not synced and an OPT is present and no result was found.
+func testNotSyncedOpt(t *testing.T, handler *Kubernetes) {
+	req := netDNS.CreateTestRequest("inexistent-ns.svc.cluster.local.", dns.TypeA, "udp")
+
+	handler.HandleDNS(req)
+	extra := []string{
+		"\n" +
+			";; OPT PSEUDOSECTION:\n" +
+			"; EDNS: version 0; flags:; udp: 1232\n" +
+			"; EDE: 14 (Not Ready): (Kubernetes objects not yet synced)",
+	}
+	checkReplySection(t, "testNotSyncedOpt", "extra", extra, req.Reply.Extra)
+}
+
+type dnsControllerWrapper struct {
+	dnsController
+	hasSynced bool
+}
+
+func (dns *dnsControllerWrapper) HasSynced() bool {
+	return dns.hasSynced
+}
+
+func (dns *dnsControllerWrapper) Modified() int64 {
+	return 12345
+}
diff --git a/osbase/net/dns/kubernetes/kubernetes.go b/osbase/net/dns/kubernetes/kubernetes.go
new file mode 100644
index 0000000..efcb60e
--- /dev/null
+++ b/osbase/net/dns/kubernetes/kubernetes.go
@@ -0,0 +1,47 @@
+// Package kubernetes provides the kubernetes backend.
+package kubernetes
+
+// Taken and modified from the Kubernetes plugin of CoreDNS, under Apache 2.0.
+
+import (
+	"context"
+	"net/netip"
+
+	"github.com/miekg/dns"
+	"k8s.io/client-go/kubernetes"
+
+	"source.monogon.dev/osbase/supervisor"
+)
+
+// Kubernetes is a DNS handler that implements the Kubernetes
+// DNS-Based Service Discovery specification.
+// https://github.com/kubernetes/dns/blob/master/docs/specification.md
+type Kubernetes struct {
+	clusterDomain string
+	nsDomain      string
+	ipRanges      []netip.Prefix
+	// A Kubernetes ClientSet with read access to endpoints and services
+	ClientSet kubernetes.Interface
+	apiConn   dnsController
+}
+
+// New returns an initialized Kubernetes. Kubernetes DNS records will be served
+// under the clusterDomain. Additionally, reverse queries for services and pods
+// are served under the given ipRanges.
+func New(clusterDomain string, ipRanges []netip.Prefix) *Kubernetes {
+	k := new(Kubernetes)
+	k.clusterDomain = dns.CanonicalName(clusterDomain)
+	k.nsDomain = "ns.dns." + k.clusterDomain
+	k.ipRanges = ipRanges
+	return k
+}
+
+// Run maintains the in-memory cache of Kubernetes services and endpoints.
+func (k *Kubernetes) Run(ctx context.Context) error {
+	k.apiConn = newdnsController(ctx, k.ClientSet)
+	k.apiConn.Start(ctx.Done())
+
+	supervisor.Signal(ctx, supervisor.SignalHealthy)
+	<-ctx.Done()
+	return ctx.Err()
+}
diff --git a/osbase/net/dns/kubernetes/metrics.go b/osbase/net/dns/kubernetes/metrics.go
new file mode 100644
index 0000000..83deeee
--- /dev/null
+++ b/osbase/net/dns/kubernetes/metrics.go
@@ -0,0 +1,44 @@
+package kubernetes
+
+// Taken and modified from the Kubernetes plugin of CoreDNS, under Apache 2.0.
+
+import (
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+
+	"source.monogon.dev/osbase/net/dns"
+)
+
+var (
+	// dnsProgrammingLatency is defined as the time it took to program a DNS
+	// instance - from the time a service or pod has changed to the time the
+	// change was propagated and was available to be served by a DNS server.
+	// The definition of this SLI can be found at https://github.com/kubernetes/community/blob/master/sig-scalability/slos/dns_programming_latency.md
+	// Note that the metrics is partially based on the time exported by the
+	// endpoints controller on the master machine. The measurement may be
+	// inaccurate if there is a clock drift between the node and master machine.
+	// The service_kind label can be one of:
+	//   * cluster_ip
+	//   * headless_with_selector
+	//   * headless_without_selector
+	dnsProgrammingLatency = dns.MetricsFactory.NewHistogramVec(prometheus.HistogramOpts{
+		Namespace: "dnsserver",
+		Subsystem: "kubernetes",
+		Name:      "dns_programming_duration_seconds",
+		// From 1 millisecond to ~17 minutes.
+		Buckets: prometheus.ExponentialBuckets(0.001, 2, 20),
+		Help:    "In Cluster DNS Programming Latency in seconds",
+	}, []string{"service_kind"})
+)
+
+func recordDNSProgrammingLatency(lastChangeTriggerTime time.Time) {
+	if !lastChangeTriggerTime.IsZero() {
+		// If we're here it means that the Endpoints object is for a headless service
+		// and that the Endpoints object was created by the endpoints-controller
+		// (because the LastChangeTriggerTime annotation is set). It means that the
+		// corresponding service is a "headless service with selector".
+		dnsProgrammingLatency.WithLabelValues("headless_with_selector").
+			Observe(time.Since(lastChangeTriggerTime).Seconds())
+	}
+}
diff --git a/osbase/net/dns/kubernetes/object/BUILD.bazel b/osbase/net/dns/kubernetes/object/BUILD.bazel
new file mode 100644
index 0000000..d851b57
--- /dev/null
+++ b/osbase/net/dns/kubernetes/object/BUILD.bazel
@@ -0,0 +1,36 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
+
+go_library(
+    name = "object",
+    srcs = [
+        "endpoint.go",
+        "informer.go",
+        "namespace.go",
+        "object.go",
+        "service.go",
+    ],
+    importpath = "source.monogon.dev/osbase/net/dns/kubernetes/object",
+    visibility = ["//osbase/net/dns/kubernetes:__subpackages__"],
+    deps = [
+        "@com_github_miekg_dns//:dns",
+        "@io_k8s_api//core/v1:core",
+        "@io_k8s_api//discovery/v1:discovery",
+        "@io_k8s_apimachinery//pkg/api/meta",
+        "@io_k8s_apimachinery//pkg/apis/meta/v1:meta",
+        "@io_k8s_apimachinery//pkg/runtime",
+        "@io_k8s_apimachinery//pkg/runtime/schema",
+        "@io_k8s_apimachinery//pkg/types",
+        "@io_k8s_client_go//tools/cache",
+    ],
+)
+
+go_test(
+    name = "object_test",
+    srcs = ["informer_test.go"],
+    embed = [":object"],
+    deps = [
+        "@io_k8s_api//core/v1:core",
+        "@io_k8s_apimachinery//pkg/apis/meta/v1:meta",
+        "@io_k8s_client_go//tools/cache",
+    ],
+)
diff --git a/osbase/net/dns/kubernetes/object/endpoint.go b/osbase/net/dns/kubernetes/object/endpoint.go
new file mode 100644
index 0000000..a675ad2
--- /dev/null
+++ b/osbase/net/dns/kubernetes/object/endpoint.go
@@ -0,0 +1,174 @@
+package object
+
+// Taken and modified from the Kubernetes plugin of CoreDNS, under Apache 2.0.
+
+import (
+	"fmt"
+	"net/netip"
+	"regexp"
+	"slices"
+	"strings"
+	"time"
+
+	api "k8s.io/api/core/v1"
+	discovery "k8s.io/api/discovery/v1"
+	meta "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+)
+
+// Endpoints is a stripped down discovery.EndpointSlice
+// with only the items we need.
+type Endpoints struct {
+	Version               string
+	Name                  string
+	Namespace             string
+	LastChangeTriggerTime time.Time
+	Index                 string
+	Addresses             []EndpointAddress
+	Ports                 []Port
+
+	*Empty
+}
+
+// EndpointAddress is a tuple that describes single IP address.
+type EndpointAddress struct {
+	// IP contains the IP address in binary format.
+	IP       string
+	Hostname string
+}
+
+// Port is a tuple that describes a single port.
+type Port struct {
+	Port     uint16
+	Name     string
+	Protocol string
+}
+
+// EndpointsKey returns a string using for the index.
+func EndpointsKey(name, namespace string) string { return name + "." + namespace }
+
+var hostnameRegexp = regexp.MustCompile(`^[-a-z0-9]{1,63}$`)
+
+// EndpointSliceToEndpoints converts a *discovery.EndpointSlice to a *Endpoints.
+func EndpointSliceToEndpoints(obj meta.Object) (meta.Object, error) {
+	ends, ok := obj.(*discovery.EndpointSlice)
+	if !ok {
+		return nil, fmt.Errorf("unexpected object %v", obj)
+	}
+	e := &Endpoints{
+		Version:   ends.GetResourceVersion(),
+		Name:      ends.GetName(),
+		Namespace: ends.GetNamespace(),
+		Index:     EndpointsKey(ends.Labels[discovery.LabelServiceName], ends.GetNamespace()),
+	}
+
+	// In case of parse error, the value is time.Zero.
+	e.LastChangeTriggerTime, _ = time.Parse(time.RFC3339Nano, ends.Annotations[api.EndpointsLastChangeTriggerTime])
+
+	e.Ports = make([]Port, 0, len(ends.Ports))
+	for _, p := range ends.Ports {
+		if p.Port != nil && *p.Port >= 1 && *p.Port <= 0xffff &&
+			p.Name != nil && *p.Name != "" && p.Protocol != nil {
+			ep := Port{
+				Port:     uint16(*p.Port),
+				Name:     strings.ToLower(*p.Name),
+				Protocol: strings.ToLower(string(*p.Protocol)),
+			}
+			e.Ports = append(e.Ports, ep)
+		}
+	}
+
+	for _, end := range ends.Endpoints {
+		if !endpointsliceReady(end.Conditions.Ready) {
+			continue
+		}
+
+		var endHostname string
+		if end.Hostname != nil {
+			endHostname = *end.Hostname
+		}
+		if endHostname != "" && !hostnameRegexp.MatchString(endHostname) {
+			endHostname = ""
+		}
+
+		for _, rawIP := range end.Addresses {
+			parsedIP, err := netip.ParseAddr(rawIP)
+			if err != nil || parsedIP.Zone() != "" {
+				continue
+			}
+			parsedIP = parsedIP.Unmap()
+			// The IP address is converted to a binary string, not human readable.
+			// That way we don't need to parse it again later.
+			ea := EndpointAddress{IP: string(parsedIP.AsSlice())}
+			if endHostname != "" {
+				ea.Hostname = endHostname
+			} else {
+				ea.Hostname = strings.ReplaceAll(strings.ReplaceAll(parsedIP.String(), ".", "-"), ":", "-")
+			}
+			e.Addresses = append(e.Addresses, ea)
+		}
+	}
+
+	*ends = discovery.EndpointSlice{}
+
+	return e, nil
+}
+
+func endpointsliceReady(ready *bool) bool {
+	// Per API docs: a nil value indicates an unknown state. In most cases
+	// consumers should interpret this unknown state as ready.
+	if ready == nil {
+		return true
+	}
+	return *ready
+}
+
+var _ runtime.Object = &Endpoints{}
+
+// DeepCopyObject implements the ObjectKind interface.
+func (e *Endpoints) DeepCopyObject() runtime.Object {
+	e1 := &Endpoints{
+		Version:   e.Version,
+		Name:      e.Name,
+		Namespace: e.Namespace,
+		Index:     e.Index,
+		Addresses: make([]EndpointAddress, len(e.Addresses)),
+		Ports:     make([]Port, len(e.Ports)),
+	}
+	copy(e1.Addresses, e.Addresses)
+	copy(e1.Ports, e.Ports)
+	return e1
+}
+
+// GetNamespace implements the metav1.Object interface.
+func (e *Endpoints) GetNamespace() string { return e.Namespace }
+
+// SetNamespace implements the metav1.Object interface.
+func (e *Endpoints) SetNamespace(namespace string) {}
+
+// GetName implements the metav1.Object interface.
+func (e *Endpoints) GetName() string { return e.Name }
+
+// SetName implements the metav1.Object interface.
+func (e *Endpoints) SetName(name string) {}
+
+// GetResourceVersion implements the metav1.Object interface.
+func (e *Endpoints) GetResourceVersion() string { return e.Version }
+
+// SetResourceVersion implements the metav1.Object interface.
+func (e *Endpoints) SetResourceVersion(version string) {}
+
+// EndpointsModified checks if the update to an endpoint is something
+// that matters to us or if they are effectively equivalent.
+func EndpointsModified(a, b *Endpoints) bool {
+	if a.Index != b.Index {
+		return true
+	}
+	if !slices.Equal(a.Addresses, b.Addresses) {
+		return true
+	}
+	if !slices.Equal(a.Ports, b.Ports) {
+		return true
+	}
+	return false
+}
diff --git a/osbase/net/dns/kubernetes/object/informer.go b/osbase/net/dns/kubernetes/object/informer.go
new file mode 100644
index 0000000..8ec1f21
--- /dev/null
+++ b/osbase/net/dns/kubernetes/object/informer.go
@@ -0,0 +1,96 @@
+package object
+
+// Taken and modified from the Kubernetes plugin of CoreDNS, under Apache 2.0.
+
+import (
+	"fmt"
+
+	"k8s.io/apimachinery/pkg/api/meta"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/client-go/tools/cache"
+)
+
+// KeyFunc works like cache.DeletionHandlingMetaNamespaceKeyFunc
+// but uses format "<name>.<namespace>" instead of "<namespace>/<name>".
+// This makes lookup for a service slightly more efficient, because we can
+// just use a slice of the query name instead of constructing a new string.
+func KeyFunc(obj interface{}) (string, error) {
+	if d, ok := obj.(cache.DeletedFinalStateUnknown); ok {
+		return d.Key, nil
+	}
+	objMeta, err := meta.Accessor(obj)
+	if err != nil {
+		return "", fmt.Errorf("object has no meta: %v", err)
+	}
+	if len(objMeta.GetNamespace()) == 0 {
+		return objMeta.GetName(), nil
+	}
+	return objMeta.GetName() + "." + objMeta.GetNamespace(), nil
+}
+
+// NewIndexerInformer is a copy of the cache.NewIndexerInformer function,
+// but allows custom process function.
+func NewIndexerInformer(lw cache.ListerWatcher, objType runtime.Object, h cache.ResourceEventHandler, indexers cache.Indexers, builder ProcessorBuilder) (cache.Indexer, cache.Controller) {
+	clientState := cache.NewIndexer(KeyFunc, indexers)
+
+	cfg := &cache.Config{
+		Queue:            cache.NewDeltaFIFOWithOptions(cache.DeltaFIFOOptions{KeyFunction: KeyFunc, KnownObjects: clientState}),
+		ListerWatcher:    lw,
+		ObjectType:       objType,
+		FullResyncPeriod: 0,
+		RetryOnError:     false,
+		Process:          builder(clientState, h),
+	}
+	return clientState, cache.New(cfg)
+}
+
+// DefaultProcessor is based on the Process function from
+// cache.NewIndexerInformer except it does a conversion.
+func DefaultProcessor(convert ToFunc) ProcessorBuilder {
+	return func(clientState cache.Indexer, h cache.ResourceEventHandler) cache.ProcessFunc {
+		return func(obj interface{}, isInitialList bool) error {
+			for _, d := range obj.(cache.Deltas) {
+				switch d.Type {
+				case cache.Sync, cache.Added, cache.Updated:
+					metaObj := d.Object.(metav1.Object)
+					obj, err := convert(metaObj)
+					if err != nil {
+						return err
+					}
+					if old, exists, err := clientState.Get(obj); err == nil && exists {
+						if err := clientState.Update(obj); err != nil {
+							return err
+						}
+						h.OnUpdate(old, obj)
+					} else {
+						if err := clientState.Add(obj); err != nil {
+							return err
+						}
+						h.OnAdd(obj, isInitialList)
+					}
+				case cache.Deleted:
+					var obj interface{}
+					obj, ok := d.Object.(cache.DeletedFinalStateUnknown)
+					if !ok {
+						var err error
+						metaObj, ok := d.Object.(metav1.Object)
+						if !ok {
+							return fmt.Errorf("unexpected object %v", d.Object)
+						}
+						obj, err = convert(metaObj)
+						if err != nil {
+							return err
+						}
+					}
+
+					if err := clientState.Delete(obj); err != nil {
+						return err
+					}
+					h.OnDelete(obj)
+				}
+			}
+			return nil
+		}
+	}
+}
diff --git a/osbase/net/dns/kubernetes/object/informer_test.go b/osbase/net/dns/kubernetes/object/informer_test.go
new file mode 100644
index 0000000..68face5
--- /dev/null
+++ b/osbase/net/dns/kubernetes/object/informer_test.go
@@ -0,0 +1,119 @@
+package object
+
+// Taken and modified from the Kubernetes plugin of CoreDNS, under Apache 2.0.
+
+import (
+	"testing"
+
+	api "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/client-go/tools/cache"
+)
+
+func TestDefaultProcessor(t *testing.T) {
+	pbuild := DefaultProcessor(ToService)
+	reh := cache.ResourceEventHandlerFuncs{}
+	idx := cache.NewIndexer(cache.DeletionHandlingMetaNamespaceKeyFunc, cache.Indexers{})
+	processor := pbuild(idx, reh)
+	testProcessor(t, processor, idx)
+}
+
+func testProcessor(t *testing.T, processor cache.ProcessFunc, idx cache.Indexer) {
+	obj := &api.Service{
+		ObjectMeta: metav1.ObjectMeta{Name: "service1", Namespace: "test1"},
+		Spec: api.ServiceSpec{
+			Type:         api.ServiceTypeExternalName,
+			ExternalName: "example.com.",
+			Ports:        []api.ServicePort{{Port: 80}},
+		},
+	}
+	obj2 := &api.Service{
+		ObjectMeta: metav1.ObjectMeta{Name: "service2", Namespace: "test1"},
+		Spec: api.ServiceSpec{
+			ClusterIP:  "5.6.7.8",
+			ClusterIPs: []string{"5.6.7.8"},
+			Ports:      []api.ServicePort{{Port: 80}},
+		},
+	}
+
+	// Add the objects
+	err := processor(cache.Deltas{
+		{Type: cache.Added, Object: obj.DeepCopy()},
+		{Type: cache.Added, Object: obj2.DeepCopy()},
+	}, false)
+	if err != nil {
+		t.Fatalf("add failed: %v", err)
+	}
+	got, exists, err := idx.Get(obj)
+	if err != nil {
+		t.Fatalf("get added object failed: %v", err)
+	}
+	if !exists {
+		t.Fatal("added object not found in index")
+	}
+	svc, ok := got.(*Service)
+	if !ok {
+		t.Fatal("object in index was incorrect type")
+	}
+	if svc.ExternalName != obj.Spec.ExternalName {
+		t.Fatalf("expected '%v', got '%v'", obj.Spec.ExternalName, svc.ExternalName)
+	}
+
+	// Update an object
+	obj.Spec.ExternalName = "2.example.com."
+	err = processor(cache.Deltas{{
+		Type:   cache.Updated,
+		Object: obj.DeepCopy(),
+	}}, false)
+	if err != nil {
+		t.Fatalf("update failed: %v", err)
+	}
+	got, exists, err = idx.Get(obj)
+	if err != nil {
+		t.Fatalf("get updated object failed: %v", err)
+	}
+	if !exists {
+		t.Fatal("updated object not found in index")
+	}
+	svc, ok = got.(*Service)
+	if !ok {
+		t.Fatal("object in index was incorrect type")
+	}
+	if svc.ExternalName != obj.Spec.ExternalName {
+		t.Fatalf("expected '%v', got '%v'", obj.Spec.ExternalName, svc.ExternalName)
+	}
+
+	// Delete an object
+	err = processor(cache.Deltas{{
+		Type:   cache.Deleted,
+		Object: obj2.DeepCopy(),
+	}}, false)
+	if err != nil {
+		t.Fatalf("delete test failed: %v", err)
+	}
+	_, exists, err = idx.Get(obj2)
+	if err != nil {
+		t.Fatalf("get deleted object failed: %v", err)
+	}
+	if exists {
+		t.Fatal("deleted object found in index")
+	}
+
+	// Delete an object via tombstone
+	key, _ := cache.MetaNamespaceKeyFunc(obj)
+	tombstone := cache.DeletedFinalStateUnknown{Key: key, Obj: svc}
+	err = processor(cache.Deltas{{
+		Type:   cache.Deleted,
+		Object: tombstone,
+	}}, false)
+	if err != nil {
+		t.Fatalf("tombstone delete test failed: %v", err)
+	}
+	_, exists, err = idx.Get(svc)
+	if err != nil {
+		t.Fatalf("get tombstone deleted object failed: %v", err)
+	}
+	if exists {
+		t.Fatal("tombstone deleted object found in index")
+	}
+}
diff --git a/osbase/net/dns/kubernetes/object/namespace.go b/osbase/net/dns/kubernetes/object/namespace.go
new file mode 100644
index 0000000..f7e7e56
--- /dev/null
+++ b/osbase/net/dns/kubernetes/object/namespace.go
@@ -0,0 +1,62 @@
+package object
+
+// Taken and modified from the Kubernetes plugin of CoreDNS, under Apache 2.0.
+
+import (
+	"fmt"
+
+	api "k8s.io/api/core/v1"
+	meta "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+)
+
+// Namespace is a stripped down api.Namespace with only the items we need.
+type Namespace struct {
+	Version string
+	Name    string
+
+	*Empty
+}
+
+// ToNamespace returns a function that converts an api.Namespace to a *Namespace.
+func ToNamespace(obj meta.Object) (meta.Object, error) {
+	ns, ok := obj.(*api.Namespace)
+	if !ok {
+		return nil, fmt.Errorf("unexpected object %v", obj)
+	}
+	n := &Namespace{
+		Version: ns.GetResourceVersion(),
+		Name:    ns.GetName(),
+	}
+	*ns = api.Namespace{}
+	return n, nil
+}
+
+var _ runtime.Object = &Namespace{}
+
+// DeepCopyObject implements the ObjectKind interface.
+func (n *Namespace) DeepCopyObject() runtime.Object {
+	n1 := &Namespace{
+		Version: n.Version,
+		Name:    n.Name,
+	}
+	return n1
+}
+
+// GetNamespace implements the metav1.Object interface.
+func (n *Namespace) GetNamespace() string { return "" }
+
+// SetNamespace implements the metav1.Object interface.
+func (n *Namespace) SetNamespace(namespace string) {}
+
+// GetName implements the metav1.Object interface.
+func (n *Namespace) GetName() string { return n.Name }
+
+// SetName implements the metav1.Object interface.
+func (n *Namespace) SetName(name string) {}
+
+// GetResourceVersion implements the metav1.Object interface.
+func (n *Namespace) GetResourceVersion() string { return n.Version }
+
+// SetResourceVersion implements the metav1.Object interface.
+func (n *Namespace) SetResourceVersion(version string) {}
diff --git a/osbase/net/dns/kubernetes/object/object.go b/osbase/net/dns/kubernetes/object/object.go
new file mode 100644
index 0000000..05724fc
--- /dev/null
+++ b/osbase/net/dns/kubernetes/object/object.go
@@ -0,0 +1,106 @@
+// Package object holds functions that convert the objects from the k8s API in
+// to a more memory efficient structures.
+//
+// Adding new fields to any of the structures defined in pod.go, endpoint.go
+// and service.go should not be done lightly as this increases the memory use
+// and will leads to OOMs in the k8s scale test.
+package object
+
+// Taken and modified from the Kubernetes plugin of CoreDNS, under Apache 2.0.
+
+import (
+	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/apimachinery/pkg/types"
+	"k8s.io/client-go/tools/cache"
+)
+
+// ToFunc converts one v1.Object to another v1.Object.
+type ToFunc func(v1.Object) (v1.Object, error)
+
+// ProcessorBuilder returns function to process cache events.
+type ProcessorBuilder func(cache.Indexer, cache.ResourceEventHandler) cache.ProcessFunc
+
+// Empty is an empty struct.
+type Empty struct{}
+
+// GetObjectKind implements the ObjectKind interface as a noop.
+func (e *Empty) GetObjectKind() schema.ObjectKind { return schema.EmptyObjectKind }
+
+// GetGenerateName implements the metav1.Object interface.
+func (e *Empty) GetGenerateName() string { return "" }
+
+// SetGenerateName implements the metav1.Object interface.
+func (e *Empty) SetGenerateName(name string) {}
+
+// GetUID implements the metav1.Object interface.
+func (e *Empty) GetUID() types.UID { return "" }
+
+// SetUID implements the metav1.Object interface.
+func (e *Empty) SetUID(uid types.UID) {}
+
+// GetGeneration implements the metav1.Object interface.
+func (e *Empty) GetGeneration() int64 { return 0 }
+
+// SetGeneration implements the metav1.Object interface.
+func (e *Empty) SetGeneration(generation int64) {}
+
+// GetSelfLink implements the metav1.Object interface.
+func (e *Empty) GetSelfLink() string { return "" }
+
+// SetSelfLink implements the metav1.Object interface.
+func (e *Empty) SetSelfLink(selfLink string) {}
+
+// GetCreationTimestamp implements the metav1.Object interface.
+func (e *Empty) GetCreationTimestamp() v1.Time { return v1.Time{} }
+
+// SetCreationTimestamp implements the metav1.Object interface.
+func (e *Empty) SetCreationTimestamp(timestamp v1.Time) {}
+
+// GetDeletionTimestamp implements the metav1.Object interface.
+func (e *Empty) GetDeletionTimestamp() *v1.Time { return &v1.Time{} }
+
+// SetDeletionTimestamp implements the metav1.Object interface.
+func (e *Empty) SetDeletionTimestamp(timestamp *v1.Time) {}
+
+// GetDeletionGracePeriodSeconds implements the metav1.Object interface.
+func (e *Empty) GetDeletionGracePeriodSeconds() *int64 { return nil }
+
+// SetDeletionGracePeriodSeconds implements the metav1.Object interface.
+func (e *Empty) SetDeletionGracePeriodSeconds(*int64) {}
+
+// GetLabels implements the metav1.Object interface.
+func (e *Empty) GetLabels() map[string]string { return nil }
+
+// SetLabels implements the metav1.Object interface.
+func (e *Empty) SetLabels(labels map[string]string) {}
+
+// GetAnnotations implements the metav1.Object interface.
+func (e *Empty) GetAnnotations() map[string]string { return nil }
+
+// SetAnnotations implements the metav1.Object interface.
+func (e *Empty) SetAnnotations(annotations map[string]string) {}
+
+// GetFinalizers implements the metav1.Object interface.
+func (e *Empty) GetFinalizers() []string { return nil }
+
+// SetFinalizers implements the metav1.Object interface.
+func (e *Empty) SetFinalizers(finalizers []string) {}
+
+// GetOwnerReferences implements the metav1.Object interface.
+func (e *Empty) GetOwnerReferences() []v1.OwnerReference { return nil }
+
+// SetOwnerReferences implements the metav1.Object interface.
+func (e *Empty) SetOwnerReferences([]v1.OwnerReference) {}
+
+// GetZZZ_DeprecatedClusterName implements the metav1.Object interface.
+func (e *Empty) GetZZZ_DeprecatedClusterName() string { return "" }
+
+// SetZZZ_DeprecatedClusterName implements the metav1.Object interface.
+func (e *Empty) SetZZZ_DeprecatedClusterName(clusterName string) {}
+
+// GetManagedFields implements the metav1.Object interface.
+func (e *Empty) GetManagedFields() []v1.ManagedFieldsEntry { return nil }
+
+// SetManagedFields implements the metav1.Object interface.
+func (e *Empty) SetManagedFields(managedFields []v1.ManagedFieldsEntry) {}
diff --git a/osbase/net/dns/kubernetes/object/service.go b/osbase/net/dns/kubernetes/object/service.go
new file mode 100644
index 0000000..5a6ca77
--- /dev/null
+++ b/osbase/net/dns/kubernetes/object/service.go
@@ -0,0 +1,144 @@
+package object
+
+// Taken and modified from the Kubernetes plugin of CoreDNS, under Apache 2.0.
+
+import (
+	"fmt"
+	"net/netip"
+	"regexp"
+	"slices"
+	"strings"
+
+	"github.com/miekg/dns"
+	api "k8s.io/api/core/v1"
+	meta "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+)
+
+// Service is a stripped down api.Service with only the items we need.
+type Service struct {
+	Version   string
+	Name      string
+	Namespace string
+	// ClusterIPs contains IP addresses in binary format.
+	ClusterIPs   []string
+	ExternalName string
+	Ports        []Port
+	Headless     bool
+
+	*Empty
+}
+
+var domainNameRegexp = regexp.MustCompile(`^([-a-z0-9]{1,63}\.)+$`)
+
+const ExternalNameInvalid = "."
+
+// ToService converts an api.Service to a *Service.
+func ToService(obj meta.Object) (meta.Object, error) {
+	svc, ok := obj.(*api.Service)
+	if !ok {
+		return nil, fmt.Errorf("unexpected object %v", obj)
+	}
+
+	s := &Service{
+		Version:   svc.GetResourceVersion(),
+		Name:      svc.GetName(),
+		Namespace: svc.GetNamespace(),
+	}
+
+	if svc.Spec.Type == api.ServiceTypeExternalName {
+		// Make the name fully qualified.
+		externalName := dns.Fqdn(svc.Spec.ExternalName)
+		// Check if the name is valid. Even names that pass Kubernetes validation
+		// can fail this check, because Kubernetes does not validate that labels
+		// must be at most 63 characters.
+		if !domainNameRegexp.MatchString(externalName) || len(externalName) > 254 {
+			externalName = ExternalNameInvalid
+		}
+		s.ExternalName = externalName
+	} else {
+		if svc.Spec.ClusterIP == api.ClusterIPNone {
+			s.Headless = true
+		} else {
+			s.ClusterIPs = make([]string, 0, len(svc.Spec.ClusterIPs))
+			for _, rawIP := range svc.Spec.ClusterIPs {
+				parsedIP, err := netip.ParseAddr(rawIP)
+				if err != nil || parsedIP.Zone() != "" {
+					continue
+				}
+				parsedIP = parsedIP.Unmap()
+				s.ClusterIPs = append(s.ClusterIPs, string(parsedIP.AsSlice()))
+			}
+
+			s.Ports = make([]Port, 0, len(svc.Spec.Ports))
+			for _, p := range svc.Spec.Ports {
+				if p.Port >= 1 && p.Port <= 0xffff && p.Name != "" {
+					ep := Port{
+						Port:     uint16(p.Port),
+						Name:     strings.ToLower(p.Name),
+						Protocol: strings.ToLower(string(p.Protocol)),
+					}
+					s.Ports = append(s.Ports, ep)
+				}
+			}
+		}
+	}
+
+	*svc = api.Service{}
+
+	return s, nil
+}
+
+var _ runtime.Object = &Service{}
+
+// DeepCopyObject implements the ObjectKind interface.
+func (s *Service) DeepCopyObject() runtime.Object {
+	s1 := &Service{
+		Version:      s.Version,
+		Name:         s.Name,
+		Namespace:    s.Namespace,
+		ClusterIPs:   make([]string, len(s.ClusterIPs)),
+		ExternalName: s.ExternalName,
+		Ports:        make([]Port, len(s.Ports)),
+		Headless:     s.Headless,
+	}
+	copy(s1.ClusterIPs, s.ClusterIPs)
+	copy(s1.Ports, s.Ports)
+	return s1
+}
+
+// GetNamespace implements the metav1.Object interface.
+func (s *Service) GetNamespace() string { return s.Namespace }
+
+// SetNamespace implements the metav1.Object interface.
+func (s *Service) SetNamespace(namespace string) {}
+
+// GetName implements the metav1.Object interface.
+func (s *Service) GetName() string { return s.Name }
+
+// SetName implements the metav1.Object interface.
+func (s *Service) SetName(name string) {}
+
+// GetResourceVersion implements the metav1.Object interface.
+func (s *Service) GetResourceVersion() string { return s.Version }
+
+// SetResourceVersion implements the metav1.Object interface.
+func (s *Service) SetResourceVersion(version string) {}
+
+// ServiceModified checks if the update to a service is something
+// that matters to us or if they are effectively equivalent.
+func ServiceModified(oldSvc, newSvc *Service) bool {
+	if oldSvc.ExternalName != newSvc.ExternalName {
+		return true
+	}
+	if oldSvc.Headless != newSvc.Headless {
+		return true
+	}
+	if !slices.Equal(oldSvc.ClusterIPs, newSvc.ClusterIPs) {
+		return true
+	}
+	if !slices.Equal(oldSvc.Ports, newSvc.Ports) {
+		return true
+	}
+	return false
+}