fix: set the default ttl to 60s (#235)

go.mod

@@ -4,6 +4,7 @@ go 1.22.7
 
 require (
 	github.com/Azure/azure-sdk-for-go/sdk/azcore v1.16.0
+	github.com/Azure/azure-sdk-for-go/sdk/azidentity v1.8.0
 	github.com/Azure/azure-sdk-for-go/sdk/resourcemanager/network/armnetwork/v4 v4.3.0
 	github.com/Azure/azure-sdk-for-go/sdk/resourcemanager/trafficmanager/armtrafficmanager v1.3.0
 	github.com/google/go-cmp v0.6.0
@@ -26,7 +27,6 @@ require go.goms.io/fleet v0.11.4
 
 require (
 	github.com/Azure/azure-sdk-for-go v68.0.0+incompatible // indirect
-	github.com/Azure/azure-sdk-for-go/sdk/azidentity v1.8.0 // indirect
 	github.com/Azure/azure-sdk-for-go/sdk/internal v1.10.0 // indirect
 	github.com/Azure/azure-sdk-for-go/sdk/resourcemanager/authorization/armauthorization/v2 v2.2.0 // indirect
 	github.com/Azure/azure-sdk-for-go/sdk/resourcemanager/compute/armcompute/v5 v5.7.0 // indirect

pkg/controllers/hub/trafficmanagerprofile/controller.go

@@ -37,6 +37,11 @@ const (
 	DNSRelativeNameFormat = "%s-%s"
 	// AzureResourceProfileNameFormat is the name format of the Azure Traffic Manager Profile created by the fleet controller.
 	AzureResourceProfileNameFormat = "fleet-%s"
+
+	// DefaultDNSTTL is in seconds. This informs the local DNS resolvers and DNS clients how long to cache DNS responses
+	// provided by this Traffic Manager profile.
+	// Defaults to 60 which is the same as the portal's default config.
+	DefaultDNSTTL = int64(60)
 )
 
 var (
@@ -170,8 +175,8 @@ func (r *Reconciler) handleUpdate(ctx context.Context, profile *fleetnetv1alpha1
 // by ignoring others.
 // The desired profile is built by the controllers and all the required fields should not be nil.
 func EqualAzureTrafficManagerProfile(current, desired armtrafficmanager.Profile) bool {
-	// location and dnsConfig is not immutable
-	if current.Properties == nil || current.Properties.MonitorConfig == nil || current.Properties.ProfileStatus == nil || current.Properties.TrafficRoutingMethod == nil {
+	// location and dnsConfig (excluding TTL) is immutable
+	if current.Properties == nil || current.Properties.MonitorConfig == nil || current.Properties.ProfileStatus == nil || current.Properties.TrafficRoutingMethod == nil || current.Properties.DNSConfig == nil {
 		return false
 	}
 
@@ -194,6 +199,10 @@ func EqualAzureTrafficManagerProfile(current, desired armtrafficmanager.Profile)
 		return false
 	}
 
+	if current.Properties.DNSConfig.TTL == nil || *current.Properties.DNSConfig.TTL != *desired.Properties.DNSConfig.TTL {
+		return false
+	}
+
 	if current.Tags == nil {
 		return false
 	}
@@ -271,6 +280,7 @@ func generateAzureTrafficManagerProfile(profile *fleetnetv1alpha1.TrafficManager
 		Properties: &armtrafficmanager.ProfileProperties{
 			DNSConfig: &armtrafficmanager.DNSConfig{
 				RelativeName: ptr.To(fmt.Sprintf(DNSRelativeNameFormat, profile.Namespace, profile.Name)),
+				TTL:          ptr.To(DefaultDNSTTL), // no default value on the server side, using 60s same as portal's default config
 			},
 			MonitorConfig: &armtrafficmanager.MonitorConfig{
 				IntervalInSeconds:         mc.IntervalInSeconds,