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AWS::EC2::PlacementGroup - AWS CloudFormation
SyntaxPropertiesReturn valuesExamples

This is the new CloudFormation Template Reference Guide. Please update your bookmarks and links. For help getting started with CloudFormation, see the AWS CloudFormation User Guide.

AWS::EC2::PlacementGroup

Specifies a placement group in which to launch instances. The strategy of the placement group determines how the instances are organized within the group.

A cluster placement group is a logical grouping of instances within a single Availability Zone that benefit from low network latency, high network throughput. A spread placement group places instances on distinct hardware. A partition placement group places groups of instances in different partitions, where instances in one partition do not share the same hardware with instances in another partition.

For more information, see Placement Groups in the Amazon EC2 User Guide.

You can optionally specify the GroupName property in your template to create a placement group with a specific name. If you don't specify a name, CloudFormation generates a unique name. Updating the GroupName value requires replacement of the placement group.

Syntax

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

JSON

{
  "Type" : "AWS::EC2::PlacementGroup",
  "Properties" : {
      "PartitionCount" : Integer,
      "SpreadLevel" : String,
      "Strategy" : String,
      "Tags" : [ Tag, ... ]
    }
}

YAML

Type: AWS::EC2::PlacementGroup
Properties:
  PartitionCount: Integer
  SpreadLevel: String
  Strategy: String
  Tags: 
    - Tag

Properties

PartitionCount

The number of partitions. Valid only when Strategy is set to partition.

Required: No

Type: Integer

Update requires: Replacement

SpreadLevel

Determines how placement groups spread instances.

  • Host – You can use host only with Outpost placement groups.

  • Rack – No usage restrictions.

Required: No

Type: String

Allowed values: host | rack

Update requires: Replacement

Strategy

The placement strategy.

Required: No

Type: String

Allowed values: cluster | spread | partition

Update requires: Replacement

Tags

The tags to apply to the new placement group.

Required: No

Type: Array of Tag

Update requires: Replacement

Return values

Ref

When you pass the logical ID of this resource to the intrinsic Ref function, Ref returns the name of the placement group.

For more information about using the Ref function, see Ref.

Fn::GetAtt

The Fn::GetAtt intrinsic function returns a value for a specified attribute of this type. The following are the available attributes and sample return values.

For more information about using the Fn::GetAtt intrinsic function, see Fn::GetAtt.

GroupName

The name of the placement group.

You can also specify GroupName in your template's Properties section to create a placement group with a specific name. If you don't specify a name, CloudFormation generates a unique name. Updating GroupName requires replacement of the placement group.

Examples

Create a placement group

The following example declares a placement group with a cluster placement strategy.

JSON

"PlacementGroup" : {
   "Type" : "AWS::EC2::PlacementGroup",
   "Properties" : {
      "Strategy" : "cluster"
   }
}

YAML

PlacementGroup:
  Type: AWS::EC2::PlacementGroup
   Properties:
     Strategy: cluster

Create a spread placement group with a specific name

The following example declares a placement group with a spread placement strategy and a specific name. The placement group is created with the name MySpreadGroup and spreads instances across distinct racks.

JSON

"PlacementGroup" : {
   "Type" : "AWS::EC2::PlacementGroup",
   "Properties" : {
      "GroupName" : "MySpreadGroup",
      "SpreadLevel" : "rack",
      "Strategy" : "spread"
   }
}

YAML

PlacementGroup:
  Type: AWS::EC2::PlacementGroup
  Properties:
    GroupName: MySpreadGroup
    SpreadLevel: rack
    Strategy: spread

Create a partition placement group with a specific name

The following example declares a placement group with a partition placement strategy, three partitions, and a specific name.

JSON

"PlacementGroup" : {
   "Type" : "AWS::EC2::PlacementGroup",
   "Properties" : {
      "GroupName" : "MyPartitionGroup",
      "PartitionCount" : 3,
      "Strategy" : "partition"
   }
}

YAML

PlacementGroup:
  Type: AWS::EC2::PlacementGroup
  Properties:
    GroupName: MyPartitionGroup
    PartitionCount: 3
    Strategy: partition