Add MachinesUpToDate condition handling in MachinePool controller

    - Updated the updateStatus method to include the new condition
    - Added unit tests
    - Fixes 10059

Signed-off-by: Satyam Bhardwaj <sbhardwaj@mirantis.com>

Author: ramessesii2

internal/controllers/machinepool/machinepool_controller.go

@@ -202,6 +202,7 @@ func (r *Reconciler) Reconcile(ctx context.Context, req ctrl.Request) (_ ctrl.Re
 			}},
 			patch.WithOwnedConditions{Conditions: []string{
 				clusterv1.PausedCondition,
+				clusterv1.MachinesUpToDateCondition,
 			}},
 		}
 		if reterr == nil {

internal/controllers/machinepool/machinepool_controller_status.go

@@ -19,7 +19,9 @@ package machinepool
 import (
 	"context"
 	"fmt"
+	"time"
 
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/utils/ptr"
 	ctrl "sigs.k8s.io/controller-runtime"
 
@@ -41,7 +43,8 @@ func (r *Reconciler) updateStatus(ctx context.Context, s *scope) error {
 
 	setReplicas(s.machinePool, hasMachinePoolMachines, s.machines)
 
-	// TODO: in future add setting conditions here
+	// Set MachinesUpToDate condition to surface when machines are not up-to-date with the spec.
+	setMachinesUpToDateCondition(ctx, s.machinePool, s.machines, hasMachinePoolMachines)
 
 	return nil
 }
@@ -73,3 +76,77 @@ func setReplicas(mp *clusterv1.MachinePool, hasMachinePoolMachines bool, machine
 	mp.Status.AvailableReplicas = ptr.To(availableReplicas)
 	mp.Status.UpToDateReplicas = ptr.To(upToDateReplicas)
 }
+
+// setMachinesUpToDateCondition sets the MachinesUpToDate condition on the MachinePool.
+func setMachinesUpToDateCondition(ctx context.Context, mp *clusterv1.MachinePool, machines []*clusterv1.Machine, hasMachinePoolMachines bool) {
+	log := ctrl.LoggerFrom(ctx)
+
+	// For MachinePool providers that don't use Machine objects (like managed pools),
+	// we derive the MachinesUpToDate condition from the infrastructure status.
+	// If InfrastructureReady is False, machines are not up-to-date.
+	if !hasMachinePoolMachines {
+		// Check if infrastructure is ready by looking at the initialization status
+		if mp.Status.Initialization.InfrastructureProvisioned == nil || !*mp.Status.Initialization.InfrastructureProvisioned {
+			conditions.Set(mp, metav1.Condition{
+				Type:    clusterv1.MachinesUpToDateCondition,
+				Status:  metav1.ConditionFalse,
+				Reason:  clusterv1.NotUpToDateReason,
+				Message: "Infrastructure is not yet provisioned",
+			})
+			return
+		}
+
+		conditions.Set(mp, metav1.Condition{
+			Type:   clusterv1.MachinesUpToDateCondition,
+			Status: metav1.ConditionTrue,
+			Reason: clusterv1.UpToDateReason,
+		})
+		return
+	}
+
+	// Only consider Machines that have an UpToDate condition or are older than 10s.
+	// This is done to ensure the MachinesUpToDate condition doesn't flicker after a new Machine is created,
+	// because it can take a bit until the UpToDate condition is set on a new Machine.
+	filteredMachines := make([]*clusterv1.Machine, 0, len(machines))
+	for _, machine := range machines {
+		if conditions.Has(machine, clusterv1.MachineUpToDateCondition) || time.Since(machine.CreationTimestamp.Time) > 10*time.Second {
+			filteredMachines = append(filteredMachines, machine)
+		}
+	}
+
+	if len(filteredMachines) == 0 {
+		conditions.Set(mp, metav1.Condition{
+			Type:   clusterv1.MachinesUpToDateCondition,
+			Status: metav1.ConditionTrue,
+			Reason: clusterv1.NoReplicasReason,
+		})
+		return
+	}
+
+	upToDateCondition, err := conditions.NewAggregateCondition(
+		filteredMachines, clusterv1.MachineUpToDateCondition,
+		conditions.TargetConditionType(clusterv1.MachinesUpToDateCondition),
+		// Using a custom merge strategy to override reasons applied during merge.
+		conditions.CustomMergeStrategy{
+			MergeStrategy: conditions.DefaultMergeStrategy(
+				conditions.ComputeReasonFunc(conditions.GetDefaultComputeMergeReasonFunc(
+					clusterv1.NotUpToDateReason,
+					clusterv1.UpToDateUnknownReason,
+					clusterv1.UpToDateReason,
+				)),
+			),
+		},
+	)
+	if err != nil {
+		log.Error(err, "Failed to aggregate Machine's UpToDate conditions")
+		conditions.Set(mp, metav1.Condition{
+			Type:    clusterv1.MachinesUpToDateCondition,
+			Status:  metav1.ConditionUnknown,
+			Reason:  clusterv1.InternalErrorReason,
+			Message: "Please check controller logs for errors",
+		})
+		return
+	}
+
+	conditions.Set(mp, *upToDateCondition)
+}

internal/controllers/machinepool/machinepool_controller_test.go

@@ -31,6 +31,7 @@ import (
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/runtime"
 	clientgoscheme "k8s.io/client-go/kubernetes/scheme"
+	"k8s.io/client-go/tools/record"
 	"k8s.io/utils/ptr"
 	ctrl "sigs.k8s.io/controller-runtime"
 	"sigs.k8s.io/controller-runtime/pkg/cache/informertest"
@@ -45,6 +46,7 @@ import (
 	"sigs.k8s.io/cluster-api/controllers/external"
 	externalfake "sigs.k8s.io/cluster-api/controllers/external/fake"
 	"sigs.k8s.io/cluster-api/util"
+	"sigs.k8s.io/cluster-api/util/conditions"
 	v1beta1conditions "sigs.k8s.io/cluster-api/util/conditions/deprecated/v1beta1"
 	"sigs.k8s.io/cluster-api/util/test/builder"
 )
@@ -1157,6 +1159,31 @@ func TestMachinePoolConditions(t *testing.T) {
 				g.Expect(infraReadyCondition.Status).To(Equal(corev1.ConditionFalse))
 			},
 		},
+		{
+			name:                "MachinesUpToDate condition set when infrastructure ready",
+			dataSecretCreated:   true,
+			infrastructureReady: true,
+			beforeFunc: func(_, _ *unstructured.Unstructured, mp *clusterv1.MachinePool, _ *corev1.NodeList) {
+				mp.Spec.ProviderIDList = []string{"azure://westus2/id-node-4", "aws://us-east-1/id-node-1"}
+				mp.Status.NodeRefs = []corev1.ObjectReference{
+					{Name: "node-1"},
+					{Name: "azure-node-4"},
+				}
+				mp.Status.Replicas = ptr.To(int32(2))
+			},
+			conditionAssertFunc: func(t *testing.T, getter v1beta1conditions.Getter) {
+				t.Helper()
+				g := NewWithT(t)
+
+				// Check that MachinesUpToDate condition is set (v1beta2 condition)
+				mp, ok := getter.(*clusterv1.MachinePool)
+				g.Expect(ok).To(BeTrue())
+				machinesUpToDateCondition := conditions.Get(mp, clusterv1.MachinesUpToDateCondition)
+				g.Expect(machinesUpToDateCondition).ToNot(BeNil())
+				g.Expect(machinesUpToDateCondition.Status).To(Equal(metav1.ConditionTrue))
+				g.Expect(machinesUpToDateCondition.Reason).To(Equal(clusterv1.UpToDateReason))
+			},
+		},
 	}
 
 	for _, tt := range testcases {
@@ -1187,6 +1214,7 @@ func TestMachinePoolConditions(t *testing.T) {
 				Client:       clientFake,
 				APIReader:    clientFake,
 				ClusterCache: clustercache.NewFakeClusterCache(clientFake, client.ObjectKey{Name: testCluster.Name, Namespace: testCluster.Namespace}),
+				recorder:     record.NewFakeRecorder(32),
 				externalTracker: external.ObjectTracker{
 					Controller:      externalfake.Controller{},
 					Cache:           &informertest.FakeInformers{},