AWS CloudFormation
User Guide (API Version 2010-05-15)
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Amazon EC2 Block Device Mapping Property

The Amazon EC2 block device mapping property is an embedded property of the AWS::EC2::Instance resource. For block device mappings for an Auto Scaling launch configuration, see AutoScaling Block Device Mapping.

Syntax

{
   "DeviceName" : String,
   "Ebs" : EC2 EBS Block Device,
   "NoDevice" : {},
   "VirtualName" : String
}     

Properties

DeviceName

The name of the device within Amazon EC2.

Required: Yes

Type: String

Ebs

Required: Conditional You can specify either VirtualName or Ebs, but not both.

Type: Amazon Elastic Block Store Block Device Property.

NoDevice

This property can be used to unmap a defined device.

Required: No

Type: an empty map: {}.

VirtualName

The name of the virtual device. The name must be in the form ephemeralX where X is a number starting from zero (0); for example, ephemeral0.

Required: Conditional You can specify either VirtualName or Ebs, but not both.

Type: String

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.

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

Block Device Mapping with an Ephemeral Drive

This example maps an ephemeral drive to device /dev/sdc.

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

Unmapping an AMI-defined Device

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

{
   "DeviceName":"/dev/sde",
   "NoDevice": {}
}        

See Also