AWS::EC2::TransitGatewayAttachment - Amazon CloudFormation
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Attaches a VPC to a transit gateway.

If you attach a VPC with a CIDR range that overlaps the CIDR range of a VPC that is already attached, the new VPC CIDR range is not propagated to the default propagation route table.

To send VPC traffic to an attached transit gateway, add a route to the VPC route table using AWS::EC2::Route.

To update tags for a VPC attachment after creation without replacing the attachment, use AWS::EC2::TransitGatewayVpcAttachment instead.


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


{ "Type" : "AWS::EC2::TransitGatewayAttachment", "Properties" : { "Options" : Options, "SubnetIds" : [ String, ... ], "Tags" : [ Tag, ... ], "TransitGatewayId" : String, "VpcId" : String } }


Type: AWS::EC2::TransitGatewayAttachment Properties: Options: Options SubnetIds: - String Tags: - Tag TransitGatewayId: String VpcId: String



The VPC attachment options.

Required: No

Type: Options

Update requires: No interruption


The IDs of one or more subnets. You can specify only one subnet per Availability Zone. You must specify at least one subnet, but we recommend that you specify two subnets for better availability. The transit gateway uses one IP address from each specified subnet.

Required: Yes

Type: Array of String

Update requires: No interruption


The tags for the attachment.

Required: No

Type: Array of Tag

Update requires: No interruption


The ID of the transit gateway.

Required: Yes

Type: String

Update requires: Replacement


The ID of the VPC.

Required: Yes

Type: String

Update requires: Replacement

Return values


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

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


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.


The ID of the attachment.

See also