Add more validation for updating node.

pkg/api/validation/validation.go

@@ -535,3 +535,15 @@ func ValidateMinion(minion *api.Minion) errs.ValidationErrorList {
 	allErrs = append(allErrs, validateLabels(minion.Labels)...)
 	return allErrs
 }
+
+// ValidateMinionUpdate tests to make sure a minion update can be applied.  Modifies oldMinion.
+func ValidateMinionUpdate(oldMinion *api.Minion, minion *api.Minion) errs.ValidationErrorList {
+	allErrs := errs.ValidationErrorList{}
+	// TODO: why we need two labels for minion.
+	oldMinion.Labels = minion.Labels
+	oldMinion.ObjectMeta.Labels = minion.ObjectMeta.Labels
+	if !reflect.DeepEqual(oldMinion, minion) {
+		allErrs = append(allErrs, fmt.Errorf("Update contains more than labels changes"))
+	}
+	return allErrs
+}

pkg/api/validation/validation_test.go

@@ -1065,3 +1065,62 @@ func TestValidateMinion(t *testing.T) {
 		}
 	}
 }
+
+func TestValidateMinionUpdate(t *testing.T) {
+	tests := []struct {
+		oldMinion api.Minion
+		minion    api.Minion
+		valid     bool
+	}{
+		{api.Minion{}, api.Minion{}, true},
+		{api.Minion{
+			ObjectMeta: api.ObjectMeta{
+				Name: "foo"}},
+			api.Minion{
+				ObjectMeta: api.ObjectMeta{
+					Name: "bar"},
+			}, false},
+		{api.Minion{
+			ObjectMeta: api.ObjectMeta{
+				Name:   "foo",
+				Labels: map[string]string{"foo": "bar"},
+			},
+		}, api.Minion{
+			ObjectMeta: api.ObjectMeta{
+				Name:   "foo",
+				Labels: map[string]string{"foo": "baz"},
+			},
+		}, true},
+		{api.Minion{
+			ObjectMeta: api.ObjectMeta{
+				Name: "foo",
+			},
+		}, api.Minion{
+			ObjectMeta: api.ObjectMeta{
+				Name:   "foo",
+				Labels: map[string]string{"foo": "baz"},
+			},
+		}, true},
+		{api.Minion{
+			ObjectMeta: api.ObjectMeta{
+				Name:   "foo",
+				Labels: map[string]string{"bar": "foo"},
+			},
+		}, api.Minion{
+			ObjectMeta: api.ObjectMeta{
+				Name:   "foo",
+				Labels: map[string]string{"foo": "baz"},
+			},
+		}, true},
+	}
+	for _, test := range tests {
+		errs := ValidateMinionUpdate(&test.oldMinion, &test.minion)
+		if test.valid && len(errs) > 0 {
+			t.Errorf("Unexpected error: %v", errs)
+			t.Logf("%#v vs %#v", test.oldMinion.ObjectMeta, test.minion.ObjectMeta)
+		}
+		if !test.valid && len(errs) == 0 {
+			t.Errorf("Unexpected non-error")
+		}
+	}
+}