AWS::EC2::Instance BlockDeviceMapping - Amazon CloudFormation
SyntaxPropertiesExamplesSee also
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AWS::EC2::Instance BlockDeviceMapping

Specifies a block device mapping for an instance. You must specify exactly one of the following properties: VirtualName, Ebs, or NoDevice.

BlockDeviceMapping is a property of the AWS::EC2::Instance resource.

Important

After the instance is running, you can modify only the DeleteOnTermination parameter for the attached volumes without interrupting the instance. Modifying any other parameter results in instance replacement.

Syntax

To declare this entity in your Amazon CloudFormation template, use the following syntax:

JSON

{
  "DeviceName" : String,
  "Ebs" : Ebs,
  "NoDevice" : Json,
  "VirtualName" : String
}

YAML

  DeviceName: String
  Ebs: 
    Ebs
  NoDevice: Json
  VirtualName: String

Properties

DeviceName

The device name (for example, /dev/sdh or xvdh).

Important

After the instance is running, this parameter is used to specify the device name of the block device mapping to update.

Required: Yes

Type: String

Update requires: Some interruptions

Ebs

Parameters used to automatically set up EBS volumes when the instance is launched.

Important

After the instance is running, you can modify only the DeleteOnTermination parameter for the attached volumes without interrupting the instance. Modifying any other parameter results in instance replacement.

Required: Conditional

Type: Ebs

Update requires: Some interruptions

NoDevice

To omit the device from the block device mapping, specify an empty string.

Important

After the instance is running, modifying this parameter results in instance replacement.

Required: Conditional

Type: Json

Update requires: Some interruptions

VirtualName

The virtual device name (ephemeralN). The name must be in the form ephemeral X where X is a number starting from zero (0). For example, an instance type with 2 available instance store volumes can specify mappings for ephemeral0 and ephemeral1. The number of available instance store volumes depends on the instance type. After you connect to the instance, you must mount the volume.

NVMe instance store volumes are automatically enumerated and assigned a device name. Including them in your block device mapping has no effect.

Constraints: For M3 instances, you must specify instance store volumes in the block device mapping for the instance. When you launch an M3 instance, we ignore any instance store volumes specified in the block device mapping for the AMI.

Important

After the instance is running, modifying this parameter results in instance replacement.

Required: Conditional

Type: String

Update requires: Some interruptions

Examples

Block device mapping with two EBS volumes

This example sets the EBS-backed root device (/dev/sda1) size to 50 GiB, and another EBS-backed device mapped to /dev/sdm that is 100 GiB in size.

JSON

"BlockDeviceMappings" : [
   {
      "DeviceName" : "/dev/sda1",
      "Ebs" : { "VolumeSize" : "50" }
   },
   {
      "DeviceName" : "/dev/sdm",
      "Ebs" : { "VolumeSize" : "100" }
   }
]

YAML

BlockDeviceMappings:
  - DeviceName: /dev/sda1
    Ebs:
      VolumeSize: 50
  - DeviceName: /dev/sdm
    Ebs:
      VolumeSize: 100

Block device mapping with an instance store volume

This example maps an instance store volume to device /dev/sdc.

JSON

"BlockDeviceMappings" : [
   {
      "DeviceName"  : "/dev/sdc",
      "VirtualName" : "ephemeral0"
   }
]

YAML

BlockDeviceMappings:
  - DeviceName: /dev/sdc
    VirtualName: ephemeral0

Unmap an AMI-defined device

To unmap a device defined in the AMI, set the NoDevice property to an empty map, as shown here:

JSON

"BlockDeviceMappings" : [
   {
      "DeviceName":"/dev/sde",
      "NoDevice": {}
   }
]

YAML

BlockDeviceMappings:
  - DeviceName: /dev/sde
    NoDevice: {}

See also