Merge pull request #1364 from hashicorp/f-lc-block-devices

block device support for launch configurations

builtin/providers/aws/resource_aws_launch_configuration.go

@@ -1,6 +1,7 @@
 package aws
 
 import (
+	"bytes"
 	"crypto/sha1"
 	"encoding/base64"
 	"encoding/hex"
@@ -10,6 +11,7 @@ import (
 
 	"github.com/hashicorp/aws-sdk-go/aws"
 	"github.com/hashicorp/aws-sdk-go/gen/autoscaling"
+	"github.com/hashicorp/aws-sdk-go/gen/ec2"
 	"github.com/hashicorp/terraform/helper/hashcode"
 	"github.com/hashicorp/terraform/helper/resource"
 	"github.com/hashicorp/terraform/helper/schema"
@@ -90,27 +92,197 @@ func resourceAwsLaunchConfiguration() *schema.Resource {
 				Optional: true,
 				ForceNew: true,
 			},
+
+			"ebs_optimized": &schema.Schema{
+				Type:     schema.TypeBool,
+				Optional: true,
+				Default:  false,
+			},
+
+			"placement_tenancy": &schema.Schema{
+				Type:     schema.TypeString,
+				Optional: true,
+				ForceNew: true,
+			},
+
+			"ebs_block_device": &schema.Schema{
+				Type:     schema.TypeSet,
+				Optional: true,
+				Computed: true,
+				Elem: &schema.Resource{
+					Schema: map[string]*schema.Schema{
+						"delete_on_termination": &schema.Schema{
+							Type:     schema.TypeBool,
+							Optional: true,
+							Default:  true,
+							ForceNew: true,
+						},
+
+						"device_name": &schema.Schema{
+							Type:     schema.TypeString,
+							Required: true,
+							ForceNew: true,
+						},
+
+						"iops": &schema.Schema{
+							Type:     schema.TypeInt,
+							Optional: true,
+							Computed: true,
+							ForceNew: true,
+						},
+
+						"snapshot_id": &schema.Schema{
+							Type:     schema.TypeString,
+							Optional: true,
+							Computed: true,
+							ForceNew: true,
+						},
+
+						"volume_size": &schema.Schema{
+							Type:     schema.TypeInt,
+							Optional: true,
+							Computed: true,
+							ForceNew: true,
+						},
+
+						"volume_type": &schema.Schema{
+							Type:     schema.TypeString,
+							Optional: true,
+							Computed: true,
+							ForceNew: true,
+						},
+					},
+				},
+				Set: func(v interface{}) int {
+					var buf bytes.Buffer
+					m := v.(map[string]interface{})
+					buf.WriteString(fmt.Sprintf("%t-", m["delete_on_termination"].(bool)))
+					buf.WriteString(fmt.Sprintf("%s-", m["device_name"].(string)))
+					// NOTE: Not considering IOPS in hash; when using gp2, IOPS can come
+					// back set to something like "33", which throws off the set
+					// calculation and generates an unresolvable diff.
+					// buf.WriteString(fmt.Sprintf("%d-", m["iops"].(int)))
+					buf.WriteString(fmt.Sprintf("%s-", m["snapshot_id"].(string)))
+					buf.WriteString(fmt.Sprintf("%d-", m["volume_size"].(int)))
+					buf.WriteString(fmt.Sprintf("%s-", m["volume_type"].(string)))
+					return hashcode.String(buf.String())
+				},
+			},
+
+			"ephemeral_block_device": &schema.Schema{
+				Type:     schema.TypeSet,
+				Optional: true,
+				Computed: true,
+				ForceNew: true,
+				Elem: &schema.Resource{
+					Schema: map[string]*schema.Schema{
+						"device_name": &schema.Schema{
+							Type:     schema.TypeString,
+							Required: true,
+						},
+
+						"virtual_name": &schema.Schema{
+							Type:     schema.TypeString,
+							Required: true,
+						},
+					},
+				},
+				Set: func(v interface{}) int {
+					var buf bytes.Buffer
+					m := v.(map[string]interface{})
+					buf.WriteString(fmt.Sprintf("%s-", m["device_name"].(string)))
+					buf.WriteString(fmt.Sprintf("%s-", m["virtual_name"].(string)))
+					return hashcode.String(buf.String())
+				},
+			},
+
+			"root_block_device": &schema.Schema{
+				// TODO: This is a set because we don't support singleton
+				//       sub-resources today. We'll enforce that the set only ever has
+				//       length zero or one below. When TF gains support for
+				//       sub-resources this can be converted.
+				Type:     schema.TypeSet,
+				Optional: true,
+				Computed: true,
+				Elem: &schema.Resource{
+					// "You can only modify the volume size, volume type, and Delete on
+					// Termination flag on the block device mapping entry for the root
+					// device volume." - bit.ly/ec2bdmap
+					Schema: map[string]*schema.Schema{
+						"delete_on_termination": &schema.Schema{
+							Type:     schema.TypeBool,
+							Optional: true,
+							Default:  true,
+							ForceNew: true,
+						},
+
+						"iops": &schema.Schema{
+							Type:     schema.TypeInt,
+							Optional: true,
+							Computed: true,
+							ForceNew: true,
+						},
+
+						"volume_size": &schema.Schema{
+							Type:     schema.TypeInt,
+							Optional: true,
+							Computed: true,
+							ForceNew: true,
+						},
+
+						"volume_type": &schema.Schema{
+							Type:     schema.TypeString,
+							Optional: true,
+							Computed: true,
+							ForceNew: true,
+						},
+					},
+				},
+				Set: func(v interface{}) int {
+					var buf bytes.Buffer
+					m := v.(map[string]interface{})
+					buf.WriteString(fmt.Sprintf("%t-", m["delete_on_termination"].(bool)))
+					// See the NOTE in "ebs_block_device" for why we skip iops here.
+					// buf.WriteString(fmt.Sprintf("%d-", m["iops"].(int)))
+					buf.WriteString(fmt.Sprintf("%d-", m["volume_size"].(int)))
+					buf.WriteString(fmt.Sprintf("%s-", m["volume_type"].(string)))
+					return hashcode.String(buf.String())
+				},
+			},
 		},
 	}
 }
 
 func resourceAwsLaunchConfigurationCreate(d *schema.ResourceData, meta interface{}) error {
 	autoscalingconn := meta.(*AWSClient).autoscalingconn
+	ec2conn := meta.(*AWSClient).ec2conn
 
-	var createLaunchConfigurationOpts autoscaling.CreateLaunchConfigurationType
+	createLaunchConfigurationOpts := autoscaling.CreateLaunchConfigurationType{
-	createLaunchConfigurationOpts.LaunchConfigurationName = aws.String(d.Get("name").(string))
+		LaunchConfigurationName: aws.String(d.Get("name").(string)),
-	createLaunchConfigurationOpts.ImageID = aws.String(d.Get("image_id").(string))
+		ImageID:                 aws.String(d.Get("image_id").(string)),
-	createLaunchConfigurationOpts.InstanceType = aws.String(d.Get("instance_type").(string))
+		InstanceType:            aws.String(d.Get("instance_type").(string)),
+		EBSOptimized:            aws.Boolean(d.Get("ebs_optimized").(bool)),
+	}
 
 	if v, ok := d.GetOk("user_data"); ok {
-		createLaunchConfigurationOpts.UserData = aws.String(base64.StdEncoding.EncodeToString([]byte(v.(string))))
+		userData := base64.StdEncoding.EncodeToString([]byte(v.(string)))
-	}
+		createLaunchConfigurationOpts.UserData = aws.String(userData)
-	if v, ok := d.GetOk("associate_public_ip_address"); ok {
-		createLaunchConfigurationOpts.AssociatePublicIPAddress = aws.Boolean(v.(bool))
 	}
+
 	if v, ok := d.GetOk("iam_instance_profile"); ok {
 		createLaunchConfigurationOpts.IAMInstanceProfile = aws.String(v.(string))
 	}
+
+	if v, ok := d.GetOk("placement_tenancy"); ok {
+		createLaunchConfigurationOpts.PlacementTenancy = aws.String(v.(string))
+	}
+
+	if v := d.Get("associate_public_ip_address"); v != nil {
+		createLaunchConfigurationOpts.AssociatePublicIPAddress = aws.Boolean(v.(bool))
+	} else {
+		createLaunchConfigurationOpts.AssociatePublicIPAddress = aws.Boolean(false)
+	}
+
 	if v, ok := d.GetOk("key_name"); ok {
 		createLaunchConfigurationOpts.KeyName = aws.String(v.(string))
 	}
@@ -120,7 +292,90 @@ func resourceAwsLaunchConfigurationCreate(d *schema.ResourceData, meta interface
 
 	if v, ok := d.GetOk("security_groups"); ok {
 		createLaunchConfigurationOpts.SecurityGroups = expandStringList(
-			v.(*schema.Set).List())
+			v.(*schema.Set).List(),
+		)
+	}
+
+	var blockDevices []autoscaling.BlockDeviceMapping
+
+	if v, ok := d.GetOk("ebs_block_device"); ok {
+		vL := v.(*schema.Set).List()
+		for _, v := range vL {
+			bd := v.(map[string]interface{})
+			ebs := &autoscaling.EBS{
+				DeleteOnTermination: aws.Boolean(bd["delete_on_termination"].(bool)),
+			}
+
+			if v, ok := bd["snapshot_id"].(string); ok && v != "" {
+				ebs.SnapshotID = aws.String(v)
+			}
+
+			if v, ok := bd["volume_size"].(int); ok && v != 0 {
+				ebs.VolumeSize = aws.Integer(v)
+			}
+
+			if v, ok := bd["volume_type"].(string); ok && v != "" {
+				ebs.VolumeType = aws.String(v)
+			}
+
+			if v, ok := bd["iops"].(int); ok && v > 0 {
+				ebs.IOPS = aws.Integer(v)
+			}
+
+			blockDevices = append(blockDevices, autoscaling.BlockDeviceMapping{
+				DeviceName: aws.String(bd["device_name"].(string)),
+				EBS:        ebs,
+			})
+		}
+	}
+
+	if v, ok := d.GetOk("ephemeral_block_device"); ok {
+		vL := v.(*schema.Set).List()
+		for _, v := range vL {
+			bd := v.(map[string]interface{})
+			blockDevices = append(blockDevices, autoscaling.BlockDeviceMapping{
+				DeviceName:  aws.String(bd["device_name"].(string)),
+				VirtualName: aws.String(bd["virtual_name"].(string)),
+			})
+		}
+	}
+
+	if v, ok := d.GetOk("root_block_device"); ok {
+		vL := v.(*schema.Set).List()
+		if len(vL) > 1 {
+			return fmt.Errorf("Cannot specify more than one root_block_device.")
+		}
+		for _, v := range vL {
+			bd := v.(map[string]interface{})
+			ebs := &autoscaling.EBS{
+				DeleteOnTermination: aws.Boolean(bd["delete_on_termination"].(bool)),
+			}
+
+			if v, ok := bd["volume_size"].(int); ok && v != 0 {
+				ebs.VolumeSize = aws.Integer(v)
+			}
+
+			if v, ok := bd["volume_type"].(string); ok && v != "" {
+				ebs.VolumeType = aws.String(v)
+			}
+
+			if v, ok := bd["iops"].(int); ok && v > 0 {
+				ebs.IOPS = aws.Integer(v)
+			}
+
+			if dn, err := fetchRootDeviceName(d.Get("image_id").(string), ec2conn); err == nil {
+				blockDevices = append(blockDevices, autoscaling.BlockDeviceMapping{
+					DeviceName: dn,
+					EBS:        ebs,
+				})
+			} else {
+				return err
+			}
+		}
+	}
+
+	if len(blockDevices) > 0 {
+		createLaunchConfigurationOpts.BlockDeviceMappings = blockDevices
 	}
 
 	if v, ok := d.GetOk("name"); ok {
@@ -151,6 +406,7 @@ func resourceAwsLaunchConfigurationCreate(d *schema.ResourceData, meta interface
 
 func resourceAwsLaunchConfigurationRead(d *schema.ResourceData, meta interface{}) error {
 	autoscalingconn := meta.(*AWSClient).autoscalingconn
+	ec2conn := meta.(*AWSClient).ec2conn
 
 	describeOpts := autoscaling.LaunchConfigurationNamesType{
 		LaunchConfigurationNames: []string{d.Id()},
@@ -197,6 +453,11 @@ func resourceAwsLaunchConfigurationRead(d *schema.ResourceData, meta interface{}
 	} else {
 		d.Set("security_groups", nil)
 	}
+
+	if err := readLCBlockDevices(d, &lc, ec2conn); err != nil {
+		return err
+	}
+
 	return nil
 }
 
@@ -217,3 +478,62 @@ func resourceAwsLaunchConfigurationDelete(d *schema.ResourceData, meta interface
 
 	return nil
 }
+
+func readLCBlockDevices(d *schema.ResourceData, lc *autoscaling.LaunchConfiguration, ec2conn *ec2.EC2) error {
+	ibds, err := readBlockDevicesFromLaunchConfiguration(d, lc, ec2conn)
+	if err != nil {
+		return err
+	}
+
+	if err := d.Set("ebs_block_device", ibds["ebs"]); err != nil {
+		return err
+	}
+	if ibds["root"] != nil {
+		if err := d.Set("root_block_device", []interface{}{ibds["root"]}); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func readBlockDevicesFromLaunchConfiguration(d *schema.ResourceData, lc *autoscaling.LaunchConfiguration, ec2conn *ec2.EC2) (
+	map[string]interface{}, error) {
+	blockDevices := make(map[string]interface{})
+	blockDevices["ebs"] = make([]map[string]interface{}, 0)
+	blockDevices["root"] = nil
+	if len(lc.BlockDeviceMappings) == 0 {
+		return nil, nil
+	}
+	rootDeviceName, err := fetchRootDeviceName(d.Get("image_id").(string), ec2conn)
+	if err == nil {
+		return nil, err
+	}
+	for _, bdm := range lc.BlockDeviceMappings {
+		bd := make(map[string]interface{})
+		if bdm.EBS != nil && bdm.EBS.DeleteOnTermination != nil {
+			bd["delete_on_termination"] = *bdm.EBS.DeleteOnTermination
+		}
+		if bdm.EBS != nil && bdm.EBS.VolumeSize != nil {
+			bd["volume_size"] = bdm.EBS.VolumeSize
+		}
+		if bdm.EBS != nil && bdm.EBS.VolumeType != nil {
+			bd["volume_type"] = *bdm.EBS.VolumeType
+		}
+		if bdm.EBS != nil && bdm.EBS.IOPS != nil {
+			bd["iops"] = *bdm.EBS.IOPS
+		}
+		if bdm.DeviceName != nil && bdm.DeviceName == rootDeviceName {
+			blockDevices["root"] = bd
+		} else {
+			if bdm.DeviceName != nil {
+				bd["device_name"] = *bdm.DeviceName
+			}
+			if bdm.EBS != nil && bdm.EBS.SnapshotID != nil {
+				bd["snapshot_id"] = *bdm.EBS.SnapshotID
+			}
+			blockDevices["ebs"] = append(blockDevices["ebs"].([]map[string]interface{}), bd)
+		}
+	}
+	return blockDevices, nil
+}

builtin/providers/aws/resource_aws_launch_configuration_test.go

@@ -2,7 +2,10 @@ package aws
 
 import (
 	"fmt"
+	"math/rand"
+	"strings"
 	"testing"
+	"time"
 
 	"github.com/hashicorp/aws-sdk-go/aws"
 	"github.com/hashicorp/aws-sdk-go/gen/autoscaling"
@@ -10,7 +13,7 @@ import (
 	"github.com/hashicorp/terraform/terraform"
 )
 
-func TestAccAWSLaunchConfiguration(t *testing.T) {
+func TestAccAWSLaunchConfiguration_withBlockDevices(t *testing.T) {
 	var conf autoscaling.LaunchConfiguration
 
 	resource.Test(t, resource.TestCase{
@@ -26,39 +29,75 @@ func TestAccAWSLaunchConfiguration(t *testing.T) {
 					resource.TestCheckResourceAttr(
 						"aws_launch_configuration.bar", "image_id", "ami-21f78e11"),
 					resource.TestCheckResourceAttr(
-						"aws_launch_configuration.bar", "name", "foobar-terraform-test"),
+						"aws_launch_configuration.bar", "instance_type", "m1.small"),
-					resource.TestCheckResourceAttr(
-						"aws_launch_configuration.bar", "instance_type", "t1.micro"),
 					resource.TestCheckResourceAttr(
 						"aws_launch_configuration.bar", "associate_public_ip_address", "true"),
 					resource.TestCheckResourceAttr(
 						"aws_launch_configuration.bar", "spot_price", ""),
 				),
 			},
+		},
+	})
+}
 
+func TestAccAWSLaunchConfiguration_withSpotPrice(t *testing.T) {
+	var conf autoscaling.LaunchConfiguration
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testAccCheckAWSLaunchConfigurationDestroy,
+		Steps: []resource.TestStep{
 			resource.TestStep{
-				Config: TestAccAWSLaunchConfigurationWithSpotPriceConfig,
+				Config: testAccAWSLaunchConfigurationWithSpotPriceConfig,
 				Check: resource.ComposeTestCheckFunc(
 					testAccCheckAWSLaunchConfigurationExists("aws_launch_configuration.bar", &conf),
-					testAccCheckAWSLaunchConfigurationAttributes(&conf),
 					resource.TestCheckResourceAttr(
 						"aws_launch_configuration.bar", "spot_price", "0.01"),
 				),
 			},
+		},
+	})
+}
 
+func TestAccAWSLaunchConfiguration_withGeneratedName(t *testing.T) {
+	var conf autoscaling.LaunchConfiguration
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testAccCheckAWSLaunchConfigurationDestroy,
+		Steps: []resource.TestStep{
 			resource.TestStep{
 				Config: testAccAWSLaunchConfigurationNoNameConfig,
 				Check: resource.ComposeTestCheckFunc(
 					testAccCheckAWSLaunchConfigurationExists("aws_launch_configuration.bar", &conf),
-					testAccCheckAWSLaunchConfigurationAttributes(&conf),
+					testAccCheckAWSLaunchConfigurationGeneratedNamePrefix(
-					resource.TestCheckResourceAttr(
+						"aws_launch_configuration.bar", "terraform-"),
-						"aws_launch_configuration.bar", "name", "terraform-foo"), // FIXME - This should fail?!?!?
 				),
 			},
 		},
 	})
 }
 
+func testAccCheckAWSLaunchConfigurationGeneratedNamePrefix(
+	resource, prefix string) resource.TestCheckFunc {
+	return func(s *terraform.State) error {
+		r, ok := s.RootModule().Resources[resource]
+		if !ok {
+			return fmt.Errorf("Resource not found")
+		}
+		name, ok := r.Primary.Attributes["name"]
+		if !ok {
+			return fmt.Errorf("Name attr not found: %#v", r.Primary.Attributes)
+		}
+		if !strings.HasPrefix(name, prefix) {
+			return fmt.Errorf("Name: %q, does not have prefix: %q", name, prefix)
+		}
+		return nil
+	}
+}
+
 func testAccCheckAWSLaunchConfigurationDestroy(s *terraform.State) error {
 	conn := testAccProvider.Meta().(*AWSClient).autoscalingconn
 
@@ -98,14 +137,40 @@ func testAccCheckAWSLaunchConfigurationAttributes(conf *autoscaling.LaunchConfig
 			return fmt.Errorf("Bad image_id: %s", *conf.ImageID)
 		}
 
-		if *conf.LaunchConfigurationName != "foobar-terraform-test" {
+		if !strings.HasPrefix(*conf.LaunchConfigurationName, "terraform-") {
 			return fmt.Errorf("Bad name: %s", *conf.LaunchConfigurationName)
 		}
 
-		if *conf.InstanceType != "t1.micro" {
+		if *conf.InstanceType != "m1.small" {
 			return fmt.Errorf("Bad instance_type: %s", *conf.InstanceType)
 		}
 
+		// Map out the block devices by name, which should be unique.
+		blockDevices := make(map[string]autoscaling.BlockDeviceMapping)
+		for _, blockDevice := range conf.BlockDeviceMappings {
+			blockDevices[*blockDevice.DeviceName] = blockDevice
+		}
+
+		// Check if the root block device exists.
+		if _, ok := blockDevices["/dev/sda1"]; !ok {
+			fmt.Errorf("block device doesn't exist: /dev/sda1")
+		}
+
+		// Check if the secondary block device exists.
+		if _, ok := blockDevices["/dev/sdb"]; !ok {
+			fmt.Errorf("block device doesn't exist: /dev/sdb")
+		}
+
+		// Check if the third block device exists.
+		if _, ok := blockDevices["/dev/sdc"]; !ok {
+			fmt.Errorf("block device doesn't exist: /dev/sdc")
+		}
+
+		// Check if the secondary block device exists.
+		if _, ok := blockDevices["/dev/sdb"]; !ok {
+			return fmt.Errorf("block device doesn't exist: /dev/sdb")
+		}
+
 		return nil
 	}
 }
@@ -143,30 +208,47 @@ func testAccCheckAWSLaunchConfigurationExists(n string, res *autoscaling.LaunchC
 	}
 }
 
-const testAccAWSLaunchConfigurationConfig = `
+var testAccAWSLaunchConfigurationConfig = fmt.Sprintf(`
 resource "aws_launch_configuration" "bar" {
-  name = "foobar-terraform-test"
+  name = "terraform-test-%d"
   image_id = "ami-21f78e11"
-  instance_type = "t1.micro"
+  instance_type = "m1.small"
   user_data = "foobar-user-data"
   associate_public_ip_address = true
-}
-`
 
-const TestAccAWSLaunchConfigurationWithSpotPriceConfig = `
+	root_block_device {
+		volume_type = "gp2"
+		volume_size = 11
+	}
+	ebs_block_device {
+		device_name = "/dev/sdb"
+		volume_size = 9
+	}
+	ebs_block_device {
+		device_name = "/dev/sdc"
+		volume_size = 10
+		volume_type = "io1"
+		iops = 100
+	}
+	ephemeral_block_device {
+		device_name = "/dev/sde"
+		virtual_name = "ephemeral0"
+	}
+}
+`, rand.New(rand.NewSource(time.Now().UnixNano())).Int())
+
+var testAccAWSLaunchConfigurationWithSpotPriceConfig = fmt.Sprintf(`
 resource "aws_launch_configuration" "bar" {
-  name = "foobar-terraform-test"
+  name = "terraform-test-%d"
   image_id = "ami-21f78e11"
   instance_type = "t1.micro"
-  user_data = "foobar-user-data"
-  associate_public_ip_address = true
   spot_price = "0.01"
 }
-`
+`, rand.New(rand.NewSource(time.Now().UnixNano())).Int())
 
 const testAccAWSLaunchConfigurationNoNameConfig = `
 resource "aws_launch_configuration" "bar" {
-   image_id = "ami-21f78e12"
+   image_id = "ami-21f78e11"
    instance_type = "t1.micro"
    user_data = "foobar-user-data-change"
    associate_public_ip_address = false

website/source/docs/providers/aws/r/launch_config.html.markdown

@@ -33,6 +33,57 @@ The following arguments are supported:
 * `security_groups` - (Optional) A list of associated security group IDS.
 * `associate_public_ip_address` - (Optional) Associate a public ip address with an instance in a VPC.
 * `user_data` - (Optional) The user data to provide when launching the instance.
+* `block_device_mapping` - (Optional) A list of block devices to add. Their keys are documented below.
+
+<a id="block-devices"></a>
+## Block devices
+
+Each of the `*_block_device` attributes controls a portion of the AWS
+Launch Configuration's "Block Device Mapping". It's a good idea to familiarize yourself with [AWS's Block Device
+Mapping docs](http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/block-device-mapping-concepts.html)
+to understand the implications of using these attributes.
+
+The `root_block_device` mapping supports the following:
+
+* `volume_type` - (Optional) The type of volume. Can be `"standard"`, `"gp2"`,
+  or `"io1"`. (Default: `"standard"`).
+* `volume_size` - (Optional) The size of the volume in gigabytes.
+* `iops` - (Optional) The amount of provisioned
+  [IOPS](http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ebs-io-characteristics.html).
+  This must be set with a `volume_type` of `"io1"`.
+* `delete_on_termination` - (Optional) Whether the volume should be destroyed
+  on instance termination (Default: `true`).
+
+Modifying any of the `root_block_device` settings requires resource
+replacement.
+
+Each `ebs_block_device` supports the following:
+
+* `device_name` - The name of the device to mount.
+* `snapshot_id` - (Optional) The Snapshot ID to mount.
+* `volume_type` - (Optional) The type of volume. Can be `"standard"`, `"gp2"`,
+  or `"io1"`. (Default: `"standard"`).
+* `volume_size` - (Optional) The size of the volume in gigabytes.
+* `iops` - (Optional) The amount of provisioned
+  [IOPS](http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ebs-io-characteristics.html).
+  This must be set with a `volume_type` of `"io1"`.
+* `delete_on_termination` - (Optional) Whether the volume should be destroyed
+  on instance termination (Default: `true`).
+
+Modifying any `ebs_block_device` currently requires resource replacement.
+
+Each `ephemeral_block_device` supports the following:
+
+* `device_name` - The name of the block device to mount on the instance.
+* `virtual_name` - The [Instance Store Device
+  Name](http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/InstanceStorage.html#InstanceStoreDeviceNames)
+  (e.g. `"ephemeral0"`)
+
+Each AWS Instance type has a different set of Instance Store block devices
+available for attachment. AWS [publishes a
+list](http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/InstanceStorage.html#StorageOnInstanceTypes)
+of which ephemeral devices are available on each type. The devices are always
+identified by the `virtual_name` in the format `"ephemeral{0..N}"`.
 
 ## Attributes Reference