Adding OnHostMaintenance option for googlecompue builder

builder/googlecompute/config.go

@@ -39,6 +39,7 @@ type Config struct {
 	Network              string            `mapstructure:"network"`
 	NetworkProjectId     string            `mapstructure:"network_project_id"`
 	OmitExternalIP       bool              `mapstructure:"omit_external_ip"`
+	OnHostMaintenance    string            `mapstructure:"on_host_maintenance"`
 	Preemptible          bool              `mapstructure:"preemptible"`
 	RawStateTimeout      string            `mapstructure:"state_timeout"`
 	Region               string            `mapstructure:"region"`
@@ -92,6 +93,12 @@ func NewConfig(raws ...interface{}) (*Config, []string, error) {
 	if c.ImageDescription == "" {
 		c.ImageDescription = "Created by Packer"
 	}
+	// Possible values:
+	//   "MIGRATE"
+	//   "TERMINATE"
+	if c.OnHostMaintenance == "" {
+		c.OnHostMaintenance = "MIGRATE"
+	}
 
 	if c.ImageName == "" {
 		img, err := interpolate.Render("packer-{{timestamp}}", nil)

builder/googlecompute/config_test.go

@@ -104,6 +104,21 @@ func TestConfigPrepare(t *testing.T) {
 			"SO VERY BAD",
 			true,
 		},
+		{
+			"on_host_maintenance",
+			nil,
+			false,
+		},
+		{
+			"on_host_maintenance",
+			"TERMINATE",
+			false,
+		},
+		{
+			"on_host_maintenance",
+			"SO VERY BAD",
+			false,
+		},
 		{
 			"preemptible",
 			nil,

builder/googlecompute/driver.go

@@ -69,6 +69,7 @@ type InstanceConfig struct {
 	Network             string
 	NetworkProjectId    string
 	OmitExternalIP      bool
+	OnHostMaintenance   string
 	Preemptible         bool
 	Region              string
 	Scopes              []string

builder/googlecompute/driver_gce.go

@@ -386,6 +386,7 @@ func (d *driverGCE) RunInstance(c *InstanceConfig) (<-chan error, error) {
 			},
 		},
 		Scheduling: &compute.Scheduling{
+			OnHostMaintenance: c.OnHostMaintenance,
 			Preemptible:       c.Preemptible,
 		},
 		ServiceAccounts: []*compute.ServiceAccount{

builder/googlecompute/step_create_instance.go

@@ -110,6 +110,7 @@ func (s *StepCreateInstance) Run(state multistep.StateBag) multistep.StepAction
 		Network:             c.Network,
 		NetworkProjectId:    c.NetworkProjectId,
 		OmitExternalIP:      c.OmitExternalIP,
+		OnHostMaintenance:   c.OnHostMaintenance,
 		Preemptible:         c.Preemptible,
 		Region:              c.Region,
 		ServiceAccountEmail: c.Account.ClientEmail,