First try at a compaction step.

builder/vmware/builder.go

@@ -243,6 +243,7 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 		&stepProvision{},
 		&stepShutdown{},
 		&stepCleanFiles{},
+		&stepCompactDisk{},
 	}
 
 	// Setup the state bag

builder/vmware/driver.go

@@ -12,6 +12,9 @@ import (
 
 // A driver is able to talk to VMware, control virtual machines, etc.
 type Driver interface {
+	// CompactDisk compacts a virtual disk.
+	CompactDisk(string) error
+
 	// CreateDisk creates a virtual disk with the given size.
 	CreateDisk(string, string) error
 
@@ -40,6 +43,20 @@ type Fusion5Driver struct {
 	AppPath string
 }
 
+func (d *Fusion5Driver) CompactDisk(diskPath string) error {
+	cmd := exec.Command(d.vdiskManagerPath(), "-d", diskPath)
+	if _, _, err := d.runAndLog(cmd); err != nil {
+		return err
+	}
+
+	cmd := exec.Command(d.vdiskManagerPath(), "-k", diskPath)
+	if _, _, err := d.runAndLog(cmd); err != nil {
+		return err
+	}
+
+	return nil
+}
+
 func (d *Fusion5Driver) CreateDisk(output string, size string) error {
 	cmd := exec.Command(d.vdiskManagerPath(), "-c", "-s", size, "-a", "lsilogic", "-t", "1", output)
 	if _, _, err := d.runAndLog(cmd); err != nil {

builder/vmware/step_compact_disk.go

@@ -0,0 +1,37 @@
+package vmware
+
+import (
+	"fmt"
+	"github.com/mitchellh/multistep"
+	"github.com/mitchellh/packer/packer"
+	"path/filepath"
+)
+
+// This step compacts the virtual disks for the VM.
+//
+// Uses:
+//   config *config
+//   driver Driver
+//   ui     packer.Ui
+//
+// Produces:
+//   <nothing>
+type stepCompactDisk struct{}
+
+func (stepCompactDisk) Run(state map[string]interface{}) multistep.StepAction {
+	config := state["config"].(*config)
+	driver := state["driver"].(Driver)
+	ui := state["ui"].(packer.Ui)
+
+	ui.Say("Compacting the disk image")
+	if err := driver.CompactDisk(config.FullDiskPath, fmt.Sprintf("%dM", config.DiskSize)); err != nil {
+		err := fmt.Errorf("Error compacting disk: %s", err)
+		state["error"] = err
+		ui.Error(err.Error())
+		return multistep.ActionHalt
+	}
+
+	return multistep.ActionContinue
+}
+
+func (stepCompactDisk) Cleanup(map[string]interface{}) {}