diff --git a/pkg/types/defaults/installconfig.go b/pkg/types/defaults/installconfig.go
index a249eed11e8..e36864903b3 100644
--- a/pkg/types/defaults/installconfig.go
+++ b/pkg/types/defaults/installconfig.go
@@ -9,6 +9,7 @@ import (
 	libvirtdefaults "github.com/openshift/installer/pkg/types/libvirt/defaults"
 	nonedefaults "github.com/openshift/installer/pkg/types/none/defaults"
 	openstackdefaults "github.com/openshift/installer/pkg/types/openstack/defaults"
+	"k8s.io/utils/pointer"
 )
 
 var (
@@ -43,23 +44,40 @@ func SetInstallConfigDefaults(c *types.InstallConfig) {
 			},
 		}
 	}
+	numberOfMasters := int64(3)
+	numberOfWorkers := int64(3)
+	if c.Platform.Libvirt != nil {
+		numberOfMasters = 1
+		numberOfWorkers = 1
+	}
 	if len(c.Machines) == 0 {
-		numberOfMasters := int64(3)
-		numberOfWorkers := int64(3)
-		if c.Platform.Libvirt != nil {
-			numberOfMasters = 1
-			numberOfWorkers = 1
-		}
 		c.Machines = []types.MachinePool{
 			{
 				Name:     "master",
-				Replicas: func(x int64) *int64 { return &x }(numberOfMasters),
+				Replicas: &numberOfMasters,
 			},
 			{
 				Name:     "worker",
-				Replicas: func(x int64) *int64 { return &x }(numberOfWorkers),
+				Replicas: &numberOfWorkers,
 			},
 		}
+	} else {
+		for i := range c.Machines {
+			switch c.Machines[i].Name {
+			case "master":
+				if c.Machines[i].Replicas == nil {
+					c.Machines[i].Replicas = &numberOfMasters
+				}
+			case "worker":
+				if c.Machines[i].Replicas == nil {
+					c.Machines[i].Replicas = &numberOfWorkers
+				}
+			default:
+				if c.Machines[i].Replicas == nil {
+					c.Machines[i].Replicas = pointer.Int64Ptr(0)
+				}
+			}
+		}
 	}
 	switch {
 	case c.Platform.AWS != nil:
diff --git a/pkg/types/defaults/installconfig_test.go b/pkg/types/defaults/installconfig_test.go
index 2a4216cdd84..bfb1caeeb07 100644
--- a/pkg/types/defaults/installconfig_test.go
+++ b/pkg/types/defaults/installconfig_test.go
@@ -16,6 +16,7 @@ import (
 	nonedefaults "github.com/openshift/installer/pkg/types/none/defaults"
 	"github.com/openshift/installer/pkg/types/openstack"
 	openstackdefaults "github.com/openshift/installer/pkg/types/openstack/defaults"
+	"k8s.io/utils/pointer"
 )
 
 func defaultInstallConfig() *types.InstallConfig {
@@ -192,7 +193,10 @@ func TestSetInstallConfigDefaults(t *testing.T) {
 			},
 			expected: func() *types.InstallConfig {
 				c := defaultInstallConfig()
-				c.Machines = []types.MachinePool{{Name: "test-machine"}}
+				c.Machines = []types.MachinePool{{
+					Name:     "test-machine",
+					Replicas: pointer.Int64Ptr(0),
+				}}
 				return c
 			}(),
 		},
diff --git a/pkg/types/machinepools.go b/pkg/types/machinepools.go
index 89d5a985464..595fa0d691f 100644
--- a/pkg/types/machinepools.go
+++ b/pkg/types/machinepools.go
@@ -12,8 +12,7 @@ type MachinePool struct {
 	Name string `json:"name"`
 
 	// Replicas is the count of machines for this machine pool.
-	// Default is 1.
-	Replicas *int64 `json:"replicas"`
+	Replicas *int64 `json:"replicas,omitempty"`
 
 	// Platform is configuration for machine pool specific to the platfrom.
 	Platform MachinePoolPlatform `json:"platform"`