builder/virtualbox/iso: append timestamp to name [GH-1365]

CHANGELOG.md

@@ -36,6 +36,8 @@ BUG FIXES:
   * builder/virtualbox/all: Seed RNG to avoid same ports. [GH-1386]
   * builder/virtualbox/all: Better error if guest additions URL couldn't be
       detected. [GH-1439]
+  * builder/virtualbox/iso: Append timestamp to default name for parallel
+      builds. [GH-1365]
   * builder/vmware/all: `ssh_host` accepts templates. [GH-1396]
   * builder/vmware/all: Don't remount floppy in VMX post step. [GH-1239]
   * builder/vmware/vmx: Do not re-add floppy disk files to VMX [GH-1361]

builder/virtualbox/iso/builder.go

@@ -116,7 +116,7 @@ func (b *Builder) Prepare(raws ...interface{}) ([]string, error) {
 	}
 
 	if b.config.VMName == "" {
-		b.config.VMName = fmt.Sprintf("packer-%s", b.config.PackerBuildName)
+		b.config.VMName = fmt.Sprintf("packer-%s-{{timestamp}}", b.config.PackerBuildName)
 	}
 
 	// Errors