🐛 Fix machine loop block when backing node does not exist

pkg/util/provider/machinecontroller/machine.go

@@ -774,7 +774,14 @@ func (c *controller) manageMachinePreservation(ctx context.Context, machine *v1a
 	if nodeName != "" {
 		nodeAnnotationValue, err = c.getNodePreserveAnnotationValue(nodeName)
 		if err != nil {
-			return
+			// If the Node object doesn't exist in the cluster yet,
+			// it cannot have a preservation annotation. Swallow the NotFound error
+			// so the machine can continue its status transition to Pending.
+			if !apierrors.IsNotFound(err) {
+				return
+			}
+			err = nil
+			nodeAnnotationValue = ""
 		}
 	}
 	var effectivePreserveValue string

pkg/util/provider/machinecontroller/machine_test.go

@@ -4448,6 +4448,20 @@ var _ = Describe("machine", func() {
 					err:                     nil,
 				},
 			}),
+			Entry("when machine has a backing node name, but node object does not exist in cluster, should swallow NotFound error and return LongRetry", testCase{
+				setup: setup{
+					nodeName:               "non-existent-node",
+					nodeAnnotationValue:    "",
+					machineAnnotationValue: "",
+					machinePhase:           v1alpha1.MachineUnknown,
+				},
+				expect: expect{
+					preserveExpiryTimeIsSet: false,
+					nodeCondition:           nil,
+					retry:                   machineutils.LongRetry,
+					err:                     nil,
+				},
+			}),
 		)
 	})
 })