Add MaxSurge to resolveSettings

pkg/instancegroups/settings.go

@@ -31,18 +31,35 @@ func resolveSettings(cluster *kops.Cluster, group *kops.InstanceGroup, numInstan
 		if rollingUpdate.MaxUnavailable == nil {
 			rollingUpdate.MaxUnavailable = def.MaxUnavailable
 		}
+		if rollingUpdate.MaxSurge == nil {
+			rollingUpdate.MaxSurge = def.MaxSurge
+		}
 	}
 
+	if rollingUpdate.MaxSurge == nil {
+		zero := intstr.FromInt(0)
+		rollingUpdate.MaxSurge = &zero
+	}
+
+	if rollingUpdate.MaxSurge.Type == intstr.String {
+		surge, _ := intstr.GetValueFromIntOrPercent(rollingUpdate.MaxSurge, numInstances, true)
+		surgeInt := intstr.FromInt(surge)
+		rollingUpdate.MaxSurge = &surgeInt
+	}
+
+	maxUnavailableDefault := intstr.FromInt(0)
+	if rollingUpdate.MaxSurge.Type == intstr.Int && rollingUpdate.MaxSurge.IntVal == 0 {
+		maxUnavailableDefault = intstr.FromInt(1)
+	}
 	if rollingUpdate.MaxUnavailable == nil || rollingUpdate.MaxUnavailable.IntVal < 0 {
-		one := intstr.FromInt(1)
-		rollingUpdate.MaxUnavailable = &one
+		rollingUpdate.MaxUnavailable = &maxUnavailableDefault
 	}
 
 	if rollingUpdate.MaxUnavailable.Type == intstr.String {
 		unavailable, err := intstr.GetValueFromIntOrPercent(rollingUpdate.MaxUnavailable, numInstances, false)
 		if err != nil {
 			// If unparseable use the default value
-			unavailable = 1
+			unavailable = maxUnavailableDefault.IntValue()
 		}
 		if unavailable <= 0 {
 			// While we round down, percentages should resolve to a minimum of 1

pkg/instancegroups/settings_test.go

@@ -37,6 +37,11 @@ func TestSettings(t *testing.T) {
 			defaultValue:    intstr.FromInt(1),
 			nonDefaultValue: intstr.FromInt(2),
 		},
+		{
+			name:            "MaxSurge",
+			defaultValue:    intstr.FromInt(0),
+			nonDefaultValue: intstr.FromInt(2),
+		},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
 			defaultCluster := &kops.RollingUpdate{}
@@ -165,3 +170,52 @@ func TestMaxUnavailable(t *testing.T) {
 		})
 	}
 }
+
+func TestMaxSurge(t *testing.T) {
+	for _, tc := range []struct {
+		numInstances int
+		value        string
+		expected     int32
+	}{
+		{
+			numInstances: 1,
+			value:        "0",
+			expected:     0,
+		},
+		{
+			numInstances: 1,
+			value:        "0%",
+			expected:     0,
+		},
+		{
+			numInstances: 10,
+			value:        "31%",
+			expected:     4,
+		},
+		{
+			numInstances: 10,
+			value:        "100%",
+			expected:     10,
+		},
+	} {
+		t.Run(fmt.Sprintf("%s %d", tc.value, tc.numInstances), func(t *testing.T) {
+			value := intstr.Parse(tc.value)
+			rollingUpdate := kops.RollingUpdate{
+				MaxSurge: &value,
+			}
+			instanceGroup := kops.InstanceGroup{
+				Spec: kops.InstanceGroupSpec{
+					RollingUpdate: &rollingUpdate,
+				},
+			}
+			resolved := resolveSettings(&kops.Cluster{}, &instanceGroup, tc.numInstances)
+			assert.Equal(t, intstr.Int, resolved.MaxSurge.Type)
+			assert.Equal(t, tc.expected, resolved.MaxSurge.IntVal)
+			if tc.expected == 0 {
+				assert.Equal(t, int32(1), resolved.MaxUnavailable.IntVal, "MaxUnavailable default")
+			} else {
+				assert.Equal(t, int32(0), resolved.MaxUnavailable.IntVal, "MaxUnavailable default")
+			}
+		})
+	}
+}