Add 'RAM_reserve_all' parameter

README.md

@@ -63,6 +63,7 @@ Hardware customization:
 * `CPU_limit` - Upper limit of available CPU resources in MHz. Inherited from source VM by default, set to `-1` for reset.
 * `RAM` - Amount of RAM in megabytes. Inherited from source VM by default.
 * `RAM_reservation` - Amount of reserved RAM in MB. Inherited from source VM by default.
+* `RAM_reserve_all` - Reserve all available RAM (bool). `false` by default. Cannot be used together with `RAM_reservation`.
 
 Provisioning:
 * `ssh_username` - [**mandatory**] username in guest OS.

config.go

@@ -81,6 +81,8 @@ func NewConfig(raws ...interface{}) (*Config, []string, error) {
 		errs = packer.MultiErrorAppend(errs, fmt.Errorf("vSphere host is required"))
 	}
 
+	errs = packer.MultiErrorAppend(errs, c.HardwareConfig.Prepare()...)
+
 	if c.RawShutdownTimeout != "" {
 		timeout, err := time.ParseDuration(c.RawShutdownTimeout)
 		if err != nil {

config_test.go

@@ -21,6 +21,14 @@ func TestTimeout(t *testing.T) {
 	}
 }
 
+func TestRAMReservation(t *testing.T) {
+	raw := minimalConfig()
+	raw["RAM_reservation"] = 1000
+	raw["RAM_reserve_all"] = true
+	_, warns, err := NewConfig(raw)
+	testConfigErr(t, warns, err)
+}
+
 func minimalConfig() map[string]interface{} {
 	return map[string]interface{}{
 		"vcenter_server": "vcenter.domain.local",
@@ -36,18 +44,18 @@ func minimalConfig() map[string]interface{} {
 
 func testConfigOk(t *testing.T, warns []string, err error) {
 	if len(warns) > 0 {
-		t.Fatalf("bad: %#v", warns)
+		t.Fatalf("Should be no warnings: %#v", warns)
 	}
 	if err != nil {
-		t.Fatalf("bad: %s", err)
+		t.Fatalf("Unexpected error: %s", err)
 	}
 }
 
 func testConfigErr(t *testing.T, warns []string, err error) {
 	if len(warns) > 0 {
-		t.Fatalf("bad: %#v", warns)
+		t.Fatalf("Should be no warnings: %#v", warns)
 	}
 	if err == nil {
-		t.Fatal("should error")
+		t.Fatal("An error is not raised")
 	}
 }

step_hardware.go

@@ -6,6 +6,7 @@ import (
 	"github.com/vmware/govmomi/vim25/types"
 	"context"
 	"github.com/vmware/govmomi/object"
+	"fmt"
 )
 
 type HardwareConfig struct {
@@ -14,6 +15,17 @@ type HardwareConfig struct {
 	CPULimit       int64 `mapstructure:"CPU_limit"`
 	RAM            int64 `mapstructure:"RAM"`
 	RAMReservation int64 `mapstructure:"RAM_reservation"`
+	RAMReserveAll  bool  `mapstructure:"RAM_reserve_all"`
+}
+
+func (c *HardwareConfig) Prepare() []error {
+	var errs []error
+
+	if c.RAMReservation > 0 && c.RAMReserveAll != false {
+		errs = append(errs, fmt.Errorf("'RAM_reservation' and 'RAM_reserve_all' cannot be used together"))
+	}
+
+	return errs
 }
 
 type StepConfigureHardware struct {
@@ -41,6 +53,8 @@ func (s *StepConfigureHardware) Run(state multistep.StateBag) multistep.StepActi
 		ramSpec.Reservation = s.config.RAMReservation
 		confSpec.MemoryAllocation = &ramSpec
 
+		confSpec.MemoryReservationLockedToMax = &s.config.RAMReserveAll
+
 		task, err := vm.Reconfigure(ctx, confSpec)
 		if err != nil {
 			state.Put("error", err)