Support A record for multile IPs for a headless services.

Non statefulset pods associating to a headless service have different IPs, but have a same hostname. In this case, external-dns registered only one A record due to attempting to register multiple A records for a same hostname for each IP. This patch now registers one A record having multiple IPs.
kubernetes-sigs · Jul 27, 2018 · 44f319e · 44f319e
1 parent aa8d04f
commit 44f319e
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Showing 2 changed files with 35 additions and 30 deletions.
diff --git a/source/service.go b/source/service.go
@@ -156,6 +156,7 @@ func (sc *serviceSource) extractHeadlessEndpoints(svc *v1.Service, hostname stri
 		return endpoints
 	}
 
+	targetsByHeadlessDomain := make(map[string][]string)
 	for _, v := range pods.Items {
 		headlessDomain := hostname
 		if v.Spec.Hostname != "" {
@@ -166,30 +167,36 @@ func (sc *serviceSource) extractHeadlessEndpoints(svc *v1.Service, hostname stri
 			log.Debugf("Generating matching endpoint %s with HostIP %s", headlessDomain, v.Status.HostIP)
 			// To reduce traffice on the DNS API only add record for running Pods. Good Idea?
 			if v.Status.Phase == v1.PodRunning {
-				if ttl.IsConfigured() {
-					endpoints = append(endpoints, endpoint.NewEndpointWithTTL(headlessDomain, endpoint.RecordTypeA, ttl, v.Status.HostIP))
-				} else {
-					endpoints = append(endpoints, endpoint.NewEndpoint(headlessDomain, endpoint.RecordTypeA, v.Status.HostIP))
-				}
+				targetsByHeadlessDomain[headlessDomain] = append(targetsByHeadlessDomain[headlessDomain], v.Status.HostIP)
 			} else {
 				log.Debugf("Pod %s is not in running phase", v.Spec.Hostname)
 			}
 		} else {
 			log.Debugf("Generating matching endpoint %s with PodIP %s", headlessDomain, v.Status.PodIP)
 			// To reduce traffice on the DNS API only add record for running Pods. Good Idea?
 			if v.Status.Phase == v1.PodRunning {
-				if ttl.IsConfigured() {
-					endpoints = append(endpoints, endpoint.NewEndpointWithTTL(headlessDomain, endpoint.RecordTypeA, ttl, v.Status.PodIP))
-				} else {
-					endpoints = append(endpoints, endpoint.NewEndpoint(headlessDomain, endpoint.RecordTypeA, v.Status.PodIP))
-				}
+				targetsByHeadlessDomain[headlessDomain] = append(targetsByHeadlessDomain[headlessDomain], v.Status.PodIP)
 			} else {
 				log.Debugf("Pod %s is not in running phase", v.Spec.Hostname)
 			}
 		}
 
 	}
 
+	headlessDomains := []string{}
+	for headlessDomain := range targetsByHeadlessDomain {
+		headlessDomains = append(headlessDomains, headlessDomain)
+	}
+	sort.Strings(headlessDomains)
+	for _, headlessDomain := range headlessDomains {
+		targets := targetsByHeadlessDomain[headlessDomain]
+		if ttl.IsConfigured() {
+			endpoints = append(endpoints, endpoint.NewEndpointWithTTL(headlessDomain, endpoint.RecordTypeA, ttl, targets...))
+		} else {
+			endpoints = append(endpoints, endpoint.NewEndpoint(headlessDomain, endpoint.RecordTypeA, targets...))
+		}
+	}
+
 	return endpoints
 }
 

diff --git a/source/service_test.go b/source/service_test.go
@@ -1235,7 +1235,7 @@ func TestHeadlessServices(t *testing.T) {
 		labels          map[string]string
 		annotations     map[string]string
 		clusterIP       string
-		podIP           string
+		podIPs          []string
 		selector        map[string]string
 		lbs             []string
 		podnames        []string
@@ -1257,7 +1257,7 @@ func TestHeadlessServices(t *testing.T) {
 				hostnameAnnotationKey: "service.example.org",
 			},
 			v1.ClusterIPNone,
-			"1.1.1.1",
+			[]string{"1.1.1.1", "1.1.1.2"},
 			map[string]string{
 				"component": "foo",
 			},
@@ -1267,7 +1267,7 @@ func TestHeadlessServices(t *testing.T) {
 			[]v1.PodPhase{v1.PodRunning, v1.PodRunning},
 			[]*endpoint.Endpoint{
 				{DNSName: "foo-0.service.example.org", Targets: endpoint.Targets{"1.1.1.1"}},
-				{DNSName: "foo-1.service.example.org", Targets: endpoint.Targets{"1.1.1.1"}},
+				{DNSName: "foo-1.service.example.org", Targets: endpoint.Targets{"1.1.1.2"}},
 			},
 			false,
 		},
@@ -1285,7 +1285,7 @@ func TestHeadlessServices(t *testing.T) {
 				ttlAnnotationKey:      "1",
 			},
 			v1.ClusterIPNone,
-			"1.1.1.1",
+			[]string{"1.1.1.1", "1.1.1.2"},
 			map[string]string{
 				"component": "foo",
 			},
@@ -1295,7 +1295,7 @@ func TestHeadlessServices(t *testing.T) {
 			[]v1.PodPhase{v1.PodRunning, v1.PodRunning},
 			[]*endpoint.Endpoint{
 				{DNSName: "foo-0.service.example.org", Targets: endpoint.Targets{"1.1.1.1"}, RecordTTL: endpoint.TTL(1)},
-				{DNSName: "foo-1.service.example.org", Targets: endpoint.Targets{"1.1.1.1"}, RecordTTL: endpoint.TTL(1)},
+				{DNSName: "foo-1.service.example.org", Targets: endpoint.Targets{"1.1.1.2"}, RecordTTL: endpoint.TTL(1)},
 			},
 			false,
 		},
@@ -1312,7 +1312,7 @@ func TestHeadlessServices(t *testing.T) {
 				hostnameAnnotationKey: "service.example.org",
 			},
 			v1.ClusterIPNone,
-			"1.1.1.1",
+			[]string{"1.1.1.1", "1.1.1.2"},
 			map[string]string{
 				"component": "foo",
 			},
@@ -1338,7 +1338,7 @@ func TestHeadlessServices(t *testing.T) {
 				hostnameAnnotationKey: "service.example.org",
 			},
 			v1.ClusterIPNone,
-			"1.1.1.1",
+			[]string{"1.1.1.1", "1.1.1.2"},
 			map[string]string{
 				"component": "foo",
 			},
@@ -1347,8 +1347,7 @@ func TestHeadlessServices(t *testing.T) {
 			[]string{"", ""},
 			[]v1.PodPhase{v1.PodRunning, v1.PodRunning},
 			[]*endpoint.Endpoint{
-				{DNSName: "service.example.org", Targets: endpoint.Targets{"1.1.1.1"}},
-				{DNSName: "service.example.org", Targets: endpoint.Targets{"1.1.1.1"}},
+				{DNSName: "service.example.org", Targets: endpoint.Targets{"1.1.1.1", "1.1.1.2"}},
 			},
 			false,
 		},
@@ -1387,7 +1386,7 @@ func TestHeadlessServices(t *testing.T) {
 						Annotations: tc.annotations,
 					},
 					Status: v1.PodStatus{
-						PodIP: tc.podIP,
+						PodIP: tc.podIPs[i],
 						Phase: tc.phases[i],
 					},
 				}
@@ -1435,7 +1434,7 @@ func TestHeadlessServicesHostIP(t *testing.T) {
 		labels          map[string]string
 		annotations     map[string]string
 		clusterIP       string
-		hostIP          string
+		hostIPs         []string
 		selector        map[string]string
 		lbs             []string
 		podnames        []string
@@ -1457,7 +1456,7 @@ func TestHeadlessServicesHostIP(t *testing.T) {
 				hostnameAnnotationKey: "service.example.org",
 			},
 			v1.ClusterIPNone,
-			"1.1.1.1",
+			[]string{"1.1.1.1", "1.1.1.2"},
 			map[string]string{
 				"component": "foo",
 			},
@@ -1467,7 +1466,7 @@ func TestHeadlessServicesHostIP(t *testing.T) {
 			[]v1.PodPhase{v1.PodRunning, v1.PodRunning},
 			[]*endpoint.Endpoint{
 				{DNSName: "foo-0.service.example.org", Targets: endpoint.Targets{"1.1.1.1"}},
-				{DNSName: "foo-1.service.example.org", Targets: endpoint.Targets{"1.1.1.1"}},
+				{DNSName: "foo-1.service.example.org", Targets: endpoint.Targets{"1.1.1.2"}},
 			},
 			false,
 		},
@@ -1485,7 +1484,7 @@ func TestHeadlessServicesHostIP(t *testing.T) {
 				ttlAnnotationKey:      "1",
 			},
 			v1.ClusterIPNone,
-			"1.1.1.1",
+			[]string{"1.1.1.1", "1.1.1.2"},
 			map[string]string{
 				"component": "foo",
 			},
@@ -1495,7 +1494,7 @@ func TestHeadlessServicesHostIP(t *testing.T) {
 			[]v1.PodPhase{v1.PodRunning, v1.PodRunning},
 			[]*endpoint.Endpoint{
 				{DNSName: "foo-0.service.example.org", Targets: endpoint.Targets{"1.1.1.1"}, RecordTTL: endpoint.TTL(1)},
-				{DNSName: "foo-1.service.example.org", Targets: endpoint.Targets{"1.1.1.1"}, RecordTTL: endpoint.TTL(1)},
+				{DNSName: "foo-1.service.example.org", Targets: endpoint.Targets{"1.1.1.2"}, RecordTTL: endpoint.TTL(1)},
 			},
 			false,
 		},
@@ -1512,7 +1511,7 @@ func TestHeadlessServicesHostIP(t *testing.T) {
 				hostnameAnnotationKey: "service.example.org",
 			},
 			v1.ClusterIPNone,
-			"1.1.1.1",
+			[]string{"1.1.1.1", "1.1.1.2"},
 			map[string]string{
 				"component": "foo",
 			},
@@ -1538,7 +1537,7 @@ func TestHeadlessServicesHostIP(t *testing.T) {
 				hostnameAnnotationKey: "service.example.org",
 			},
 			v1.ClusterIPNone,
-			"1.1.1.1",
+			[]string{"1.1.1.1", "1.1.1.2"},
 			map[string]string{
 				"component": "foo",
 			},
@@ -1547,8 +1546,7 @@ func TestHeadlessServicesHostIP(t *testing.T) {
 			[]string{"", ""},
 			[]v1.PodPhase{v1.PodRunning, v1.PodRunning},
 			[]*endpoint.Endpoint{
-				{DNSName: "service.example.org", Targets: endpoint.Targets{"1.1.1.1"}},
-				{DNSName: "service.example.org", Targets: endpoint.Targets{"1.1.1.1"}},
+				{DNSName: "service.example.org", Targets: endpoint.Targets{"1.1.1.1", "1.1.1.2"}},
 			},
 			false,
 		},
@@ -1587,7 +1585,7 @@ func TestHeadlessServicesHostIP(t *testing.T) {
 						Annotations: tc.annotations,
 					},
 					Status: v1.PodStatus{
-						HostIP: tc.hostIP,
+						HostIP: tc.hostIPs[i],
 						Phase:  tc.phases[i],
 					},
 				}