Use FQDN from tailscale client

Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com>

integration/general_test.go

@@ -69,10 +69,10 @@ func TestPingAllByIP(t *testing.T) {
 
 	t.Logf("%d successful pings out of %d", success, len(allClients)*len(allIps))
 
-	// err = scenario.Shutdown()
-	// if err != nil {
-	// 	t.Errorf("failed to tear down scenario: %s", err)
-	// }
+	err = scenario.Shutdown()
+	if err != nil {
+		t.Errorf("failed to tear down scenario: %s", err)
+	}
 }
 
 func TestPingAllByHostname(t *testing.T) {
@@ -94,6 +94,7 @@ func TestPingAllByHostname(t *testing.T) {
 	}
 
 	var allClients []*tsic.TailscaleInContainer
+	var allHostnames []string
 
 	for namespace := range spec {
 		clients, err := scenario.GetClients(namespace)
@@ -109,13 +110,22 @@ func TestPingAllByHostname(t *testing.T) {
 		t.Errorf("failed wait for tailscale clients to be in sync: %s", err)
 	}
 
+	for _, client := range allClients {
+		fqdn, err := client.FQDN()
+		if err != nil {
+			t.Errorf("failed to get fqdn of client %s: %s", t.Name(), err)
+		}
+
+		allHostnames = append(allHostnames, fqdn)
+	}
+
 	success := 0
 
 	for _, client := range allClients {
-		for _, peer := range allClients {
-			err := client.Ping(peer.Hostname)
+		for _, hostname := range allHostnames {
+			err := client.Ping(hostname)
 			if err != nil {
-				t.Errorf("failed to ping %s from %s: %s", peer.Hostname, client.Hostname, err)
+				t.Errorf("failed to ping %s from %s: %s", hostname, client.Hostname, err)
 			} else {
 				success++
 			}

integration/tsic/tsic.go

@@ -204,6 +204,15 @@ func (t *TailscaleInContainer) Status() (*ipnstate.Status, error) {
 	return &status, err
 }
 
+func (t *TailscaleInContainer) FQDN() (string, error) {
+	status, err := t.Status()
+	if err != nil {
+		return "", fmt.Errorf("failed to get FQDN: %w", err)
+	}
+
+	return status.Self.DNSName, nil
+}
+
 func (t *TailscaleInContainer) WaitForPeers(expected int) error {
 	return t.pool.Retry(func() error {
 		status, err := t.Status()