plugin/kubernetes: Create records for portless services (#2052)

inject sentinels for portless services

plugin/backend_lookup.go

@@ -172,6 +172,11 @@ func SRV(b ServiceBackend, zone string, state request.Request, opt Options) (rec
 		w[serv.Priority] += weight
 	}
 	for _, serv := range services {
+		// Don't add the entry if the port is -1 (invalid). The kubernetes plugin uses port -1 when a service/endpoint
+		// does not have any declared ports.
+		if serv.Port == -1 {
+			continue
+		}
 		w1 := 100.0 / float64(w[serv.Priority])
 		if serv.Weight == 0 {
 			w1 *= 100

plugin/kubernetes/handler_test.go

@@ -124,6 +124,22 @@ var dnsTestCases = []test.Case{
 			test.A("hdls1.testns.svc.cluster.local.	5	IN	A	172.0.0.5"),
 		},
 	},
+	// A Service (Headless and Portless)
+	{
+		Qname: "hdlsprtls.testns.svc.cluster.local.", Qtype: dns.TypeA,
+		Rcode: dns.RcodeSuccess,
+		Answer: []dns.RR{
+			test.A("hdlsprtls.testns.svc.cluster.local.	5	IN	A	172.0.0.20"),
+		},
+	},
+	// An Endpoint with no port
+	{
+		Qname: "172-0-0-20.hdlsprtls.testns.svc.cluster.local.", Qtype: dns.TypeA,
+		Rcode: dns.RcodeSuccess,
+		Answer: []dns.RR{
+			test.A("172-0-0-20.hdlsprtls.testns.svc.cluster.local.	5	IN	A	172.0.0.20"),
+		},
+	},
 	// An Endpoint ip
 	{
 		Qname: "172-0-0-2.hdls1.testns.svc.cluster.local.", Qtype: dns.TypeA,
@@ -169,6 +185,14 @@ var dnsTestCases = []test.Case{
 			test.A("dup-name.hdls1.testns.svc.cluster.local.	5	IN	A	172.0.0.5"),
 		},
 	},
+	// SRV Service (Headless and portless)
+	{
+		Qname: "*.*.hdlsprtls.testns.svc.cluster.local.", Qtype: dns.TypeSRV,
+		Rcode: dns.RcodeSuccess,
+		Ns: []dns.RR{
+			test.SOA("cluster.local.	300	IN	SOA	ns.dns.cluster.local. hostmaster.cluster.local. 1499347823 7200 1800 86400 60"),
+		},
+	},
 	// AAAA
 	{
 		Qname: "5678-abcd--2.hdls1.testns.svc.cluster.local", Qtype: dns.TypeAAAA,
@@ -444,6 +468,16 @@ var svcIndex = map[string][]*api.Service{
 			Type: api.ServiceTypeExternalName,
 		},
 	}},
+	"hdlsprtls.testns": {{
+		ObjectMeta: meta.ObjectMeta{
+			Name:      "hdlsprtls",
+			Namespace: "testns",
+		},
+		Spec: api.ServiceSpec{
+			Type:      api.ServiceTypeClusterIP,
+			ClusterIP: api.ClusterIPNone,
+		},
+	}},
 }
 
 func (APIConnServeTest) SvcIndex(s string) []*api.Service {
@@ -539,6 +573,22 @@ var epsIndex = map[string][]*api.Endpoints{
 			Namespace: "testns",
 		},
 	}},
+	"hdlsprtls.testns": {{
+		Subsets: []api.EndpointSubset{
+			{
+				Addresses: []api.EndpointAddress{
+					{
+						IP: "172.0.0.20",
+					},
+				},
+				Ports: []api.EndpointPort{},
+			},
+		},
+		ObjectMeta: meta.ObjectMeta{
+			Name:      "hdlsprtls",
+			Namespace: "testns",
+		},
+	}},
 }
 
 func (APIConnServeTest) EpIndex(s string) []*api.Endpoints {

plugin/kubernetes/kubernetes.go

@@ -459,13 +459,17 @@ func (k *Kubernetes) findServices(r recordRequest, zone string) (services []msg.
 					for _, addr := range eps.Addresses {
 
 						// See comments in parse.go parseRequest about the endpoint handling.
-
 						if r.endpoint != "" {
 							if !match(r.endpoint, endpointHostname(addr, k.endpointNameMode)) {
 								continue
 							}
 						}
 
+						if len(eps.Ports) == 0 {
+							// add a sentinel port (-1) entry so we create records for services without any declared ports
+							eps.Ports = append(eps.Ports, api.EndpointPort{Port: -1})
+						}
+
 						for _, p := range eps.Ports {
 							if !(match(r.port, p.Name) && match(r.protocol, string(p.Protocol))) {
 								continue
@@ -496,6 +500,10 @@ func (k *Kubernetes) findServices(r recordRequest, zone string) (services []msg.
 		}
 
 		// ClusterIP service
+		if len(svc.Spec.Ports) == 0 {
+			// add a sentinel port (-1) entry so we create records for services without any declared ports
+			svc.Spec.Ports = append(svc.Spec.Ports, api.ServicePort{Port: -1})
+		}
 		for _, p := range svc.Spec.Ports {
 			if !(match(r.port, p.Name) && match(r.protocol, string(p.Protocol))) {
 				continue