forcibly prevent ephemeral drives from being created in the amazon-ebs builder, when no_ephemeral is set

builder/amazon/common/step_run_source_instance.go

@@ -35,6 +35,7 @@ type StepRunSourceInstance struct {
 	UserData                          string
 	UserDataFile                      string
 	VolumeTags                        TagMap
+	NoEphemeral                       bool
 
 	instanceId string
 }
@@ -116,6 +117,26 @@ func (s *StepRunSourceInstance) Run(ctx context.Context, state multistep.StateBa
 		EbsOptimized:        &s.EbsOptimized,
 	}
 
+	if s.NoEphemeral {
+		// This is only relevant for windows guests. Ephemeral drives by
+		// default are assigned to drive names xvdca-xvdcz.
+		// When vms are launched from the AWS console, they're automatically
+		// removed from the block devices if the user hasn't said to use them,
+		// but the SDK does not perform this cleanup. The following code just
+		// manually removes the ephemeral drives from the mapping so that they
+		// don't clutter up console views and cause confusion.
+		log.Printf("no_ephemeral was set, so creating drives xvdca-xvdcz as empty mappings")
+		DefaultEphemeralDeviceLetters := "abcdefghijklmnopqrstuvwxyz"
+		for i := 0; i < len(DefaultEphemeralDeviceLetters); i++ {
+
+			bd := &ec2.BlockDeviceMapping{
+				DeviceName: aws.String("xvdc" + string(DefaultEphemeralDeviceLetters[i])),
+				NoDevice:   aws.String(""),
+			}
+			runOpts.BlockDeviceMappings = append(runOpts.BlockDeviceMappings, bd)
+		}
+	}
+
 	if s.EnableT2Unlimited {
 		creditOption := "unlimited"
 		runOpts.CreditSpecification = &ec2.CreditSpecificationRequest{CpuCredits: &creditOption}

builder/amazon/ebs/builder.go

@@ -53,6 +53,12 @@ type Config struct {
 	// engine](/docs/templates/engine.html), see [Build template
 	// data](#build-template-data) for more information.
 	VolumeRunTags awscommon.TagMap `mapstructure:"run_volume_tags"`
+	// If you set this flag, we'll add clauses to the
+	// launch_block_device_mappings that make sure ephemeral drives don't show
+	// up in the EC2 console. If you launched from the EC2 console, you'd get
+	// this automatically, but the SDK does not provide this service.
+	// This only applies when you are not running spot instances.
+	NoEphemeral bool `mapstructure:"no_ephemeral" required:"false"`
 
 	ctx interpolate.Context
 }
@@ -181,6 +187,7 @@ func (b *Builder) Run(ctx context.Context, ui packer.Ui, hook packer.Hook) (pack
 			UserData:                          b.config.UserData,
 			UserDataFile:                      b.config.UserDataFile,
 			VolumeTags:                        b.config.VolumeRunTags,
+			NoEphemeral:                       b.config.NoEphemeral,
 		}
 	}