plugin/k8s_external: Resolve headless services (#5505)

*add option for resolving headless Services without external IPs in k8s_external

Signed-off-by: Tomas Kohout <tomas.kohout1995@gmail.com>

1 files changed, 54 insertions, 3 deletions

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)
+	}
+}
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