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-rw-r--r--plugin/kubernetes/external.go142
-rw-r--r--plugin/kubernetes/external_test.go88
-rw-r--r--plugin/kubernetes/kubernetes.go4
-rw-r--r--plugin/kubernetes/ns.go19
-rw-r--r--plugin/kubernetes/ns_test.go57
-rw-r--r--plugin/kubernetes/xfr.go2
6 files changed, 264 insertions, 48 deletions
diff --git a/plugin/kubernetes/external.go b/plugin/kubernetes/external.go
index 702bdc30c..b6531ab68 100644
--- a/plugin/kubernetes/external.go
+++ b/plugin/kubernetes/external.go
@@ -11,9 +11,21 @@ import (
"github.com/miekg/dns"
)
+// Those constants are used to distinguish between records in ExternalServices headless
+// return values.
+// They are always appendedn to key in a map which is
+// either base service key eg. /com/example/namespace/service/endpoint or
+// /com/example/namespace/service/_http/_tcp/port.protocol
+// this will allow us to distinguish services in implementation of Transfer protocol
+// see plugin/k8s_external/transfer.go
+const (
+ Endpoint = "endpoint"
+ PortProtocol = "port.protocol"
+)
+
// External implements the ExternalFunc call from the external plugin.
-// It returns any services matching in the services' ExternalIPs.
-func (k *Kubernetes) External(state request.Request) ([]msg.Service, int) {
+// It returns any services matching in the services' ExternalIPs and if enabled, headless endpoints..
+func (k *Kubernetes) External(state request.Request, headless bool) ([]msg.Service, int) {
if state.QType() == dns.TypePTR {
ip := dnsutil.ExtractAddressFromReverse(state.Name())
if ip != "" {
@@ -33,10 +45,11 @@ func (k *Kubernetes) External(state request.Request) ([]msg.Service, int) {
if last < 0 {
return nil, dns.RcodeServerFailure
}
- // We are dealing with a fairly normal domain name here, but we still need to have the service
- // and the namespace:
- // service.namespace.<base>
- var port, protocol string
+ // We are dealing with a fairly normal domain name here, but we still need to have the service,
+ // namespace and if present, endpoint:
+ // service.namespace.<base> or
+ // endpoint.service.namespace.<base>
+ var port, protocol, endpoint string
namespace := segs[last]
if !k.namespaceExposed(namespace) {
return nil, dns.RcodeNameError
@@ -49,7 +62,10 @@ func (k *Kubernetes) External(state request.Request) ([]msg.Service, int) {
service := segs[last]
last--
- if last == 1 {
+ if last == 0 {
+ endpoint = stripUnderscore(segs[last])
+ last--
+ } else if last == 1 {
protocol = stripUnderscore(segs[last])
port = stripUnderscore(segs[last-1])
last -= 2
@@ -60,8 +76,13 @@ func (k *Kubernetes) External(state request.Request) ([]msg.Service, int) {
return nil, dns.RcodeNameError
}
+ var (
+ endpointsList []*object.Endpoints
+ serviceList []*object.Service
+ )
+
idx := object.ServiceKey(service, namespace)
- serviceList := k.APIConn.SvcIndex(idx)
+ serviceList = k.APIConn.SvcIndex(idx)
services := []msg.Service{}
zonePath := msg.Path(state.Zone, coredns)
@@ -75,16 +96,47 @@ func (k *Kubernetes) External(state request.Request) ([]msg.Service, int) {
continue
}
- for _, ip := range svc.ExternalIPs {
- for _, p := range svc.Ports {
- if !(matchPortAndProtocol(port, p.Name, protocol, string(p.Protocol))) {
+ if headless && len(svc.ExternalIPs) == 0 && (svc.Headless() || endpoint != "") {
+ if endpointsList == nil {
+ endpointsList = k.APIConn.EpIndex(idx)
+ }
+ // Endpoint query or headless service
+ for _, ep := range endpointsList {
+ if object.EndpointsKey(svc.Name, svc.Namespace) != ep.Index {
continue
}
- rcode = dns.RcodeSuccess
- s := msg.Service{Host: ip, Port: int(p.Port), TTL: k.ttl}
- s.Key = strings.Join([]string{zonePath, svc.Namespace, svc.Name}, "/")
- services = append(services, s)
+ for _, eps := range ep.Subsets {
+ for _, addr := range eps.Addresses {
+ if endpoint != "" && !match(endpoint, endpointHostname(addr, k.endpointNameMode)) {
+ continue
+ }
+
+ for _, p := range eps.Ports {
+ if !(matchPortAndProtocol(port, p.Name, protocol, p.Protocol)) {
+ continue
+ }
+ s := msg.Service{Host: addr.IP, Port: int(p.Port), TTL: k.ttl}
+ s.Key = strings.Join([]string{zonePath, svc.Namespace, svc.Name, endpointHostname(addr, k.endpointNameMode)}, "/")
+
+ services = append(services, s)
+ }
+ }
+ }
+ }
+ continue
+ } else {
+ for _, ip := range svc.ExternalIPs {
+ for _, p := range svc.Ports {
+ if !(matchPortAndProtocol(port, p.Name, protocol, string(p.Protocol))) {
+ continue
+ }
+ rcode = dns.RcodeSuccess
+ s := msg.Service{Host: ip, Port: int(p.Port), TTL: k.ttl}
+ s.Key = strings.Join([]string{zonePath, svc.Namespace, svc.Name}, "/")
+
+ services = append(services, s)
+ }
}
}
}
@@ -96,31 +148,65 @@ func (k *Kubernetes) External(state request.Request) ([]msg.Service, int) {
}
// ExternalAddress returns the external service address(es) for the CoreDNS service.
-func (k *Kubernetes) ExternalAddress(state request.Request) []dns.RR {
+func (k *Kubernetes) ExternalAddress(state request.Request, headless bool) []dns.RR {
// If CoreDNS is running inside the Kubernetes cluster: k.nsAddrs() will return the external IPs of the services
// targeting the CoreDNS Pod.
// If CoreDNS is running outside of the Kubernetes cluster: k.nsAddrs() will return the first non-loopback IP
// address seen on the local system it is running on. This could be the wrong answer if coredns is using the *bind*
// plugin to bind to a different IP address.
- return k.nsAddrs(true, state.Zone)
+ return k.nsAddrs(true, headless, state.Zone)
}
-// ExternalServices returns all services with external IPs
-func (k *Kubernetes) ExternalServices(zone string) (services []msg.Service) {
+// ExternalServices returns all services with external IPs and if enabled headless services
+func (k *Kubernetes) ExternalServices(zone string, headless bool) (services []msg.Service, headlessServices map[string][]msg.Service) {
zonePath := msg.Path(zone, coredns)
+ headlessServices = make(map[string][]msg.Service)
for _, svc := range k.APIConn.ServiceList() {
- for _, ip := range svc.ExternalIPs {
- for _, p := range svc.Ports {
- s := msg.Service{Host: ip, Port: int(p.Port), TTL: k.ttl}
- s.Key = strings.Join([]string{zonePath, svc.Namespace, svc.Name}, "/")
- services = append(services, s)
- s.Key = strings.Join(append([]string{zonePath, svc.Namespace, svc.Name}, strings.ToLower("_"+string(p.Protocol)), strings.ToLower("_"+string(p.Name))), "/")
- s.TargetStrip = 2
- services = append(services, s)
+ // Endpoints and headless services
+ if headless && len(svc.ExternalIPs) == 0 && svc.Headless() {
+ idx := object.ServiceKey(svc.Name, svc.Namespace)
+ endpointsList := k.APIConn.EpIndex(idx)
+
+ for _, ep := range endpointsList {
+ for _, eps := range ep.Subsets {
+ for _, addr := range eps.Addresses {
+ // we need to have some answers grouped together
+ // 1. for endpoint requests eg. endpoint-0.service.example.com - will always have one endpoint
+ // 2. for service requests eg. service.example.com - can have multiple endpoints
+ // 3. for port.protocol requests eg. _http._tcp.service.example.com - can have multiple endpoints
+ for _, p := range eps.Ports {
+ s := msg.Service{Host: addr.IP, Port: int(p.Port), TTL: k.ttl}
+ baseSvc := strings.Join([]string{zonePath, svc.Namespace, svc.Name}, "/")
+ s.Key = strings.Join([]string{baseSvc, endpointHostname(addr, k.endpointNameMode)}, "/")
+ headlessServices[strings.Join([]string{baseSvc, Endpoint}, "/")] = append(headlessServices[strings.Join([]string{baseSvc, Endpoint}, "/")], s)
+
+ // As per spec unnamed ports do not have a srv record
+ // https://github.com/kubernetes/dns/blob/master/docs/specification.md#232---srv-records
+ if p.Name == "" {
+ continue
+ }
+ s.Host = msg.Domain(s.Key)
+ s.Key = strings.Join(append([]string{zonePath, svc.Namespace, svc.Name}, strings.ToLower("_"+string(p.Protocol)), strings.ToLower("_"+string(p.Name))), "/")
+ headlessServices[strings.Join([]string{s.Key, PortProtocol}, "/")] = append(headlessServices[strings.Join([]string{s.Key, PortProtocol}, "/")], s)
+ }
+ }
+ }
+ }
+ continue
+ } else {
+ for _, ip := range svc.ExternalIPs {
+ for _, p := range svc.Ports {
+ s := msg.Service{Host: ip, Port: int(p.Port), TTL: k.ttl}
+ s.Key = strings.Join([]string{zonePath, svc.Namespace, svc.Name}, "/")
+ services = append(services, s)
+ s.Key = strings.Join(append([]string{zonePath, svc.Namespace, svc.Name}, strings.ToLower("_"+string(p.Protocol)), strings.ToLower("_"+string(p.Name))), "/")
+ s.TargetStrip = 2
+ services = append(services, s)
+ }
}
}
}
- return services
+ return services, headlessServices
}
//ExternalSerial returns the serial of the external zone
diff --git a/plugin/kubernetes/external_test.go b/plugin/kubernetes/external_test.go
index b0e89e000..670d2b9b2 100644
--- a/plugin/kubernetes/external_test.go
+++ b/plugin/kubernetes/external_test.go
@@ -43,6 +43,22 @@ var extCases = []struct {
{
Qname: "svc0.svc-nons.example.com.", Rcode: dns.RcodeNameError,
},
+ {
+ Qname: "svc-headless.testns.example.com.", Rcode: dns.RcodeSuccess,
+ Msg: []msg.Service{
+ {Host: "1.2.3.4", Port: 80, TTL: 5, Weight: 50, Key: "/c/org/example/testns/svc-headless"},
+ {Host: "1.2.3.5", Port: 80, TTL: 5, Weight: 50, Key: "/c/org/example/testns/svc-headless"},
+ },
+ },
+ {
+ Qname: "endpoint-0.svc-headless.testns.example.com.", Rcode: dns.RcodeSuccess,
+ Msg: []msg.Service{
+ {Host: "1.2.3.4", Port: 80, TTL: 5, Weight: 100, Key: "/c/org/example/testns/svc-headless/endpoint-0"},
+ },
+ },
+ {
+ Qname: "endpoint-1.svc-nons.testns.example.com.", Rcode: dns.RcodeNameError,
+ },
}
func TestExternal(t *testing.T) {
@@ -54,7 +70,7 @@ func TestExternal(t *testing.T) {
for i, tc := range extCases {
state := testRequest(tc.Qname)
- svc, rcode := k.External(state)
+ svc, rcode := k.External(state, true)
if x := tc.Rcode; x != rcode {
t.Errorf("Test %d, expected rcode %d, got %d", i, x, rcode)
@@ -75,15 +91,23 @@ func TestExternal(t *testing.T) {
type external struct{}
-func (external) HasSynced() bool { return true }
-func (external) Run() {}
-func (external) Stop() error { return nil }
-func (external) EpIndexReverse(string) []*object.Endpoints { return nil }
-func (external) SvcIndexReverse(string) []*object.Service { return nil }
-func (external) SvcExtIndexReverse(string) []*object.Service { return nil }
-func (external) Modified(bool) int64 { return 0 }
-func (external) EpIndex(s string) []*object.Endpoints { return nil }
-func (external) EndpointsList() []*object.Endpoints { return nil }
+func (external) HasSynced() bool { return true }
+func (external) Run() {}
+func (external) Stop() error { return nil }
+func (external) EpIndexReverse(string) []*object.Endpoints { return nil }
+func (external) SvcIndexReverse(string) []*object.Service { return nil }
+func (external) SvcExtIndexReverse(string) []*object.Service { return nil }
+func (external) Modified(bool) int64 { return 0 }
+func (external) EpIndex(s string) []*object.Endpoints {
+ return epIndexExternal[s]
+}
+func (external) EndpointsList() []*object.Endpoints {
+ var eps []*object.Endpoints
+ for _, ep := range epIndexExternal {
+ eps = append(eps, ep...)
+ }
+ return eps
+}
func (external) GetNodeByName(ctx context.Context, name string) (*api.Node, error) { return nil, nil }
func (external) SvcIndex(s string) []*object.Service { return svcIndexExternal[s] }
func (external) PodIndex(string) []*object.Pod { return nil }
@@ -94,6 +118,41 @@ func (external) GetNamespaceByName(name string) (*object.Namespace, error) {
}, nil
}
+var epIndexExternal = map[string][]*object.Endpoints{
+ "svc-headless.testns": {
+ {
+ Name: "svc-headless",
+ Namespace: "testns",
+ Index: "svc-headless.testns",
+ Subsets: []object.EndpointSubset{
+ {
+ Ports: []object.EndpointPort{
+ {
+ Port: 80,
+ Name: "http",
+ Protocol: "TCP",
+ },
+ },
+ Addresses: []object.EndpointAddress{
+ {
+ IP: "1.2.3.4",
+ Hostname: "endpoint-svc-0",
+ NodeName: "test-node",
+ TargetRefName: "endpoint-svc-0",
+ },
+ {
+ IP: "1.2.3.5",
+ Hostname: "endpoint-svc-1",
+ NodeName: "test-node",
+ TargetRefName: "endpoint-svc-1",
+ },
+ },
+ },
+ },
+ },
+ },
+}
+
var svcIndexExternal = map[string][]*object.Service{
"svc1.testns": {
{
@@ -115,6 +174,15 @@ var svcIndexExternal = map[string][]*object.Service{
Ports: []api.ServicePort{{Name: "http", Protocol: "tcp", Port: 80}},
},
},
+ "svc-headless.testns": {
+ {
+ Name: "svc-headless",
+ Namespace: "testns",
+ Type: api.ServiceTypeClusterIP,
+ ClusterIPs: []string{api.ClusterIPNone},
+ Ports: []api.ServicePort{{Name: "http", Protocol: "tcp", Port: 80}},
+ },
+ },
}
func (external) ServiceList() []*object.Service {
diff --git a/plugin/kubernetes/kubernetes.go b/plugin/kubernetes/kubernetes.go
index 62e39648e..10d8b7e90 100644
--- a/plugin/kubernetes/kubernetes.go
+++ b/plugin/kubernetes/kubernetes.go
@@ -112,7 +112,7 @@ func (k *Kubernetes) Services(ctx context.Context, state request.Request, exact
case dns.TypeNS:
// We can only get here if the qname equals the zone, see ServeDNS in handler.go.
- nss := k.nsAddrs(false, state.Zone)
+ nss := k.nsAddrs(false, false, state.Zone)
var svcs []msg.Service
for _, ns := range nss {
if ns.Header().Rrtype == dns.TypeA {
@@ -127,7 +127,7 @@ func (k *Kubernetes) Services(ctx context.Context, state request.Request, exact
}
if isDefaultNS(state.Name(), state.Zone) {
- nss := k.nsAddrs(false, state.Zone)
+ nss := k.nsAddrs(false, false, state.Zone)
var svcs []msg.Service
for _, ns := range nss {
if ns.Header().Rrtype == dns.TypeA && state.QType() == dns.TypeA {
diff --git a/plugin/kubernetes/ns.go b/plugin/kubernetes/ns.go
index 3e6a30586..eb40c3488 100644
--- a/plugin/kubernetes/ns.go
+++ b/plugin/kubernetes/ns.go
@@ -13,7 +13,7 @@ func isDefaultNS(name, zone string) bool {
// nsAddrs returns the A or AAAA records for the CoreDNS service in the cluster. If the service cannot be found,
// it returns a record for the local address of the machine we're running on.
-func (k *Kubernetes) nsAddrs(external bool, zone string) []dns.RR {
+func (k *Kubernetes) nsAddrs(external, headless bool, zone string) []dns.RR {
var (
svcNames []string
svcIPs []net.IP
@@ -31,10 +31,21 @@ func (k *Kubernetes) nsAddrs(external bool, zone string) []dns.RR {
for _, svc := range svcs {
if external {
svcName := strings.Join([]string{svc.Name, svc.Namespace, zone}, ".")
- for _, exIP := range svc.ExternalIPs {
- svcNames = append(svcNames, svcName)
- svcIPs = append(svcIPs, net.ParseIP(exIP))
+
+ if headless && svc.Headless() {
+ for _, s := range endpoint.Subsets {
+ for _, a := range s.Addresses {
+ svcNames = append(svcNames, endpointHostname(a, k.endpointNameMode)+"."+svcName)
+ svcIPs = append(svcIPs, net.ParseIP(a.IP))
+ }
+ }
+ } else {
+ for _, exIP := range svc.ExternalIPs {
+ svcNames = append(svcNames, svcName)
+ svcIPs = append(svcIPs, net.ParseIP(exIP))
+ }
}
+
continue
}
svcName := strings.Join([]string{svc.Name, svc.Namespace, Svc, zone}, ".")
diff --git a/plugin/kubernetes/ns_test.go b/plugin/kubernetes/ns_test.go
index 3ad12cb29..82426a907 100644
--- a/plugin/kubernetes/ns_test.go
+++ b/plugin/kubernetes/ns_test.go
@@ -103,7 +103,7 @@ func TestNsAddrs(t *testing.T) {
k.APIConn = &APIConnTest{}
k.localIPs = []net.IP{net.ParseIP("10.244.0.20")}
- cdrs := k.nsAddrs(false, k.Zones[0])
+ cdrs := k.nsAddrs(false, false, k.Zones[0])
if len(cdrs) != 3 {
t.Fatalf("Expected 3 results, got %v", len(cdrs))
@@ -137,13 +137,36 @@ func TestNsAddrs(t *testing.T) {
}
}
+func TestNsAddrsExternalHeadless(t *testing.T) {
+ k := New([]string{"example.com."})
+ k.APIConn = &APIConnTest{}
+ k.localIPs = []net.IP{net.ParseIP("10.244.0.20")}
+
+ // there are only headless sevices
+ cdrs := k.nsAddrs(true, true, k.Zones[0])
+
+ if len(cdrs) != 1 {
+ t.Fatalf("Expected 0 results, got %v", cdrs)
+ }
+
+ cdr := cdrs[0]
+ expected := "10.244.0.20"
+ if cdr.(*dns.A).A.String() != expected {
+ t.Errorf("Expected A address to be %q, got %q", expected, cdr.(*dns.A).A.String())
+ }
+ expected = "10-244-0-20.hdls-dns-service.kube-system.example.com."
+ if cdr.Header().Name != expected {
+ t.Errorf("Expected record name to be %q, got %q", expected, cdr.Header().Name)
+ }
+}
+
func TestNsAddrsExternal(t *testing.T) {
k := New([]string{"example.com."})
k.APIConn = &APIConnTest{}
k.localIPs = []net.IP{net.ParseIP("10.244.0.20")}
// initially no services have an external IP ...
- cdrs := k.nsAddrs(true, k.Zones[0])
+ cdrs := k.nsAddrs(true, false, k.Zones[0])
if len(cdrs) != 0 {
t.Fatalf("Expected 0 results, got %v", len(cdrs))
@@ -151,7 +174,7 @@ func TestNsAddrsExternal(t *testing.T) {
// Add an external IP to one of the services ...
svcs[0].ExternalIPs = []string{"1.2.3.4"}
- cdrs = k.nsAddrs(true, k.Zones[0])
+ cdrs = k.nsAddrs(true, false, k.Zones[0])
if len(cdrs) != 1 {
t.Fatalf("Expected 1 results, got %v", len(cdrs))
@@ -166,3 +189,31 @@ func TestNsAddrsExternal(t *testing.T) {
t.Errorf("Expected record name to be %q, got %q", expected, cdr.Header().Name)
}
}
+
+func TestNsAddrsExternalWithPreexistingExternalIP(t *testing.T) {
+ k := New([]string{"example.com."})
+ k.APIConn = &APIConnTest{}
+ k.localIPs = []net.IP{net.ParseIP("10.244.0.20")}
+
+ svcs[0].ExternalIPs = []string{"1.2.3.4"}
+
+ // initially no services have an external IP ...
+ cdrs := k.nsAddrs(true, false, k.Zones[0])
+
+ if len(cdrs) != 1 {
+ t.Fatalf("Expected 1 results, got %v", len(cdrs))
+ }
+
+ if len(cdrs) != 1 {
+ t.Fatalf("Expected 1 results, got %v", len(cdrs))
+ }
+ cdr := cdrs[0]
+ expected := "1.2.3.4"
+ if cdr.(*dns.A).A.String() != expected {
+ t.Errorf("Expected A address to be %q, got %q", expected, cdr.(*dns.A).A.String())
+ }
+ expected = "dns-service.kube-system.example.com."
+ if cdr.Header().Name != expected {
+ t.Errorf("Expected record name to be %q, got %q", expected, cdr.Header().Name)
+ }
+} \ No newline at end of file
diff --git a/plugin/kubernetes/xfr.go b/plugin/kubernetes/xfr.go
index e29a4a7a7..1990bea40 100644
--- a/plugin/kubernetes/xfr.go
+++ b/plugin/kubernetes/xfr.go
@@ -42,7 +42,7 @@ func (k *Kubernetes) Transfer(zone string, serial uint32) (<-chan []dns.RR, erro
}
ch <- soa
- nsAddrs := k.nsAddrs(false, zone)
+ nsAddrs := k.nsAddrs(false, false, zone)
nsHosts := make(map[string]struct{})
for _, nsAddr := range nsAddrs {
nsHost := nsAddr.Header().Name
generated by cgit v1.2.3 (git 2.39.1) at 2025-07-30 20:54:15 +0000