Add in-place to machineset controller (oldMS)

Author: fabriziopandini

internal/controllers/machinedeployment/machinedeployment_rollout_planner_test.go

@@ -160,6 +160,19 @@ func (p *rolloutPlanner) reconcileReplicasPendingAcknowledgeMove(ctx context.Con
 	}
 }
 
+// reconcileNewMachineSet reconciles replica number for the new MS.
+// Note: In case of scale down this function does not make consideration about possible impacts on availability.
+// This is considered acceptable because historically it never led to any problem, but we might revisit this in the future
+// because some limitations of this approach are becoming more evident, e.g.
+//
+//	when users scale down the MD, the operation might temporarily breach min availability
+//
+// There are code paths specifically added to prevent this issue to become more relevant when doing in-place updates;
+// e.g. the MS controller will give highest delete priority to machines still updating in-place,
+// which are also unavailable machines.
+//
+// Notably, there is also not agreement yet on a different way forward because e.g. limiting scale down of the
+// new MS could lead e.g. to completing in place upgrade of machines that will be otherwise deleted.
 func (p *rolloutPlanner) reconcileNewMachineSet(ctx context.Context) error {
 	log := ctrl.LoggerFrom(ctx)
 	allMSs := append(p.oldMSs, p.newMS)

internal/controllers/machinedeployment/machinedeployment_rollout_rollingupdate.go

@@ -1140,12 +1140,31 @@ func fakeMachine(name string, options ...fakeMachinesOption) *clusterv1.Machine
 	return p
 }
 
+func withOwnerMachineSet(msName string) fakeMachinesOption {
+	return func(m *clusterv1.Machine) {
+		m.OwnerReferences = []metav1.OwnerReference{
+			{
+				APIVersion: clusterv1.GroupVersion.String(),
+				Kind:       "MachineSet",
+				Name:       msName,
+				Controller: ptr.To(true),
+			},
+		}
+	}
+}
+
 func withCreationTimestamp(t time.Time) fakeMachinesOption {
 	return func(m *clusterv1.Machine) {
 		m.CreationTimestamp = metav1.Time{Time: t}
 	}
 }
 
+func withMachineFinalizer() fakeMachinesOption {
+	return func(m *clusterv1.Machine) {
+		m.Finalizers = []string{clusterv1.MachineFinalizer}
+	}
+}
+
 func withDeletionTimestamp() fakeMachinesOption {
 	return func(m *clusterv1.Machine) {
 		m.DeletionTimestamp = ptr.To(metav1.Time{Time: time.Now()})
@@ -1158,6 +1177,18 @@ func withStaleDeletionTimestamp() fakeMachinesOption {
 	}
 }
 
+func withMachineLabels(labels map[string]string) fakeMachinesOption {
+	return func(m *clusterv1.Machine) {
+		m.Labels = labels
+	}
+}
+
+func withMachineAnnotations(annotations map[string]string) fakeMachinesOption {
+	return func(m *clusterv1.Machine) {
+		m.Annotations = annotations
+	}
+}
+
 func withStaleDrain() fakeMachinesOption {
 	return func(m *clusterv1.Machine) {
 		if m.Status.Deletion == nil {
@@ -1172,3 +1203,17 @@ func withCondition(c metav1.Condition) fakeMachinesOption {
 		conditions.Set(m, c)
 	}
 }
+
+func withHealthyStatus() fakeMachinesOption {
+	return func(m *clusterv1.Machine) {
+		m.Status = clusterv1.MachineStatus{
+			NodeRef: clusterv1.MachineNodeReference{Name: "some-node"},
+			Conditions: []metav1.Condition{
+				{
+					Type:   clusterv1.MachineNodeHealthyCondition,
+					Status: metav1.ConditionUnknown,
+				},
+			},
+		}
+	}
+}