KillTimeout can be modified in place

scheduler/annotate.go

@@ -159,17 +159,12 @@ func annotateTask(diff *structs.TaskDiff, parent *structs.TaskGroupDiff) {
 		}
 	}
 
-	// All changes to primitive fields result in a destructive update.
+	// All changes to primitive fields result in a destructive update except
+	// KillTimeout
 	destructive := false
-	if len(diff.Fields) != 0 {
-		destructive = true
-	}
-
-	// Changes that can be done in-place are log configs, services and
-	// constraints.
-	for _, oDiff := range diff.Objects {
-		switch oDiff.Name {
-		case "LogConfig", "Service", "Constraint":
+	for _, fDiff := range diff.Fields {
+		switch fDiff.Name {
+		case "KillTimeout":
 			continue
 		default:
 			destructive = true
@@ -177,6 +172,20 @@ func annotateTask(diff *structs.TaskDiff, parent *structs.TaskGroupDiff) {
 		}
 	}
 
+	// Object changes that can be done in-place are log configs, services,
+	// constraints.
+	if !destructive {
+		for _, oDiff := range diff.Objects {
+			switch oDiff.Name {
+			case "LogConfig", "Service", "Constraint":
+				continue
+			default:
+				destructive = true
+				break
+			}
+		}
+	}
+
 	if destructive {
 		diff.Annotations = append(diff.Annotations, AnnotationForcesDestructiveUpdate)
 	} else {

scheduler/annotate_test.go

@@ -347,6 +347,21 @@ func TestAnnotateTask(t *testing.T) {
 			Parent:  &structs.TaskGroupDiff{Type: structs.DiffTypeEdited},
 			Desired: AnnotationForcesInplaceUpdate,
 		},
+		{
+			Diff: &structs.TaskDiff{
+				Type: structs.DiffTypeEdited,
+				Fields: []*structs.FieldDiff{
+					{
+						Type: structs.DiffTypeEdited,
+						Name: "KillTimeout",
+						Old:  "200",
+						New:  "2000000",
+					},
+				},
+			},
+			Parent:  &structs.TaskGroupDiff{Type: structs.DiffTypeEdited},
+			Desired: AnnotationForcesInplaceUpdate,
+		},
 		// Task deleted new parent
 		{
 			Diff: &structs.TaskDiff{