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](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/Welcome.html).

# AWS::EC2::Subnet
<a name="aws-resource-ec2-subnet"></a>

Specifies a subnet for the specified VPC.

For an IPv4 only subnet, specify an IPv4 CIDR block. If the VPC has an IPv6 CIDR block, you can create an IPv6 only subnet or a dual stack subnet instead. For an IPv6 only subnet, specify an IPv6 CIDR block. For a dual stack subnet, specify both an IPv4 CIDR block and an IPv6 CIDR block.

For more information, see [Subnets for your VPC](https://docs.aws.amazon.com/vpc/latest/userguide/configure-subnets.html) in the *Amazon VPC User Guide*.

## Syntax
<a name="aws-resource-ec2-subnet-syntax"></a>

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

### JSON
<a name="aws-resource-ec2-subnet-syntax.json"></a>

```
{
  "Type" : "AWS::EC2::Subnet",
  "Properties" : {
      "[AssignIpv6AddressOnCreation](#cfn-ec2-subnet-assignipv6addressoncreation)" : Boolean,
      "[AvailabilityZone](#cfn-ec2-subnet-availabilityzone)" : String,
      "[AvailabilityZoneId](#cfn-ec2-subnet-availabilityzoneid)" : String,
      "[CidrBlock](#cfn-ec2-subnet-cidrblock)" : String,
      "[EnableDns64](#cfn-ec2-subnet-enabledns64)" : Boolean,
      "[EnableLniAtDeviceIndex](#cfn-ec2-subnet-enablelniatdeviceindex)" : Integer,
      "[Ipv4IpamPoolId](#cfn-ec2-subnet-ipv4ipampoolid)" : String,
      "[Ipv4NetmaskLength](#cfn-ec2-subnet-ipv4netmasklength)" : Integer,
      "[Ipv6CidrBlock](#cfn-ec2-subnet-ipv6cidrblock)" : String,
      "[Ipv6IpamPoolId](#cfn-ec2-subnet-ipv6ipampoolid)" : String,
      "[Ipv6Native](#cfn-ec2-subnet-ipv6native)" : Boolean,
      "[Ipv6NetmaskLength](#cfn-ec2-subnet-ipv6netmasklength)" : Integer,
      "[MapPublicIpOnLaunch](#cfn-ec2-subnet-mappubliciponlaunch)" : Boolean,
      "[OutpostArn](#cfn-ec2-subnet-outpostarn)" : String,
      "[PrivateDnsNameOptionsOnLaunch](#cfn-ec2-subnet-privatednsnameoptionsonlaunch)" : PrivateDnsNameOptionsOnLaunch,
      "[Tags](#cfn-ec2-subnet-tags)" : [ Tag, ... ],
      "[VpcId](#cfn-ec2-subnet-vpcid)" : String
    }
}
```

### YAML
<a name="aws-resource-ec2-subnet-syntax.yaml"></a>

```
Type: AWS::EC2::Subnet
Properties:
  [AssignIpv6AddressOnCreation](#cfn-ec2-subnet-assignipv6addressoncreation): Boolean
  [AvailabilityZone](#cfn-ec2-subnet-availabilityzone): String
  [AvailabilityZoneId](#cfn-ec2-subnet-availabilityzoneid): String
  [CidrBlock](#cfn-ec2-subnet-cidrblock): String
  [EnableDns64](#cfn-ec2-subnet-enabledns64): Boolean
  [EnableLniAtDeviceIndex](#cfn-ec2-subnet-enablelniatdeviceindex): Integer
  [Ipv4IpamPoolId](#cfn-ec2-subnet-ipv4ipampoolid): String
  [Ipv4NetmaskLength](#cfn-ec2-subnet-ipv4netmasklength): Integer
  [Ipv6CidrBlock](#cfn-ec2-subnet-ipv6cidrblock): String
  [Ipv6IpamPoolId](#cfn-ec2-subnet-ipv6ipampoolid): String
  [Ipv6Native](#cfn-ec2-subnet-ipv6native): Boolean
  [Ipv6NetmaskLength](#cfn-ec2-subnet-ipv6netmasklength): Integer
  [MapPublicIpOnLaunch](#cfn-ec2-subnet-mappubliciponlaunch): Boolean
  [OutpostArn](#cfn-ec2-subnet-outpostarn): String
  [PrivateDnsNameOptionsOnLaunch](#cfn-ec2-subnet-privatednsnameoptionsonlaunch): 
    PrivateDnsNameOptionsOnLaunch
  [Tags](#cfn-ec2-subnet-tags): 
    - Tag
  [VpcId](#cfn-ec2-subnet-vpcid): String
```

## Properties
<a name="aws-resource-ec2-subnet-properties"></a>

`AssignIpv6AddressOnCreation`  <a name="cfn-ec2-subnet-assignipv6addressoncreation"></a>
Indicates whether a network interface created in this subnet receives an IPv6 address. The default value is `false`.  
If you specify `AssignIpv6AddressOnCreation`, you must also specify an IPv6 CIDR block.  
*Required*: No  
*Type*: Boolean  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`AvailabilityZone`  <a name="cfn-ec2-subnet-availabilityzone"></a>
The Availability Zone of the subnet.  
If you update this property, you must also update the `CidrBlock` property.  
*Required*: No  
*Type*: String  
*Update requires*: [Replacement](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-replacement)

`AvailabilityZoneId`  <a name="cfn-ec2-subnet-availabilityzoneid"></a>
The AZ ID of the subnet.  
*Required*: No  
*Type*: String  
*Update requires*: [Replacement](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-replacement)

`CidrBlock`  <a name="cfn-ec2-subnet-cidrblock"></a>
The IPv4 CIDR block assigned to the subnet.  
If you update this property, we create a new subnet, and then delete the existing one.  
*Required*: Conditional  
*Type*: String  
*Update requires*: [Replacement](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-replacement)

`EnableDns64`  <a name="cfn-ec2-subnet-enabledns64"></a>
Indicates whether DNS queries made to the Amazon-provided DNS Resolver in this subnet should return synthetic IPv6 addresses for IPv4-only destinations.  
You must first configure a NAT gateway in a public subnet (separate from the subnet containing the IPv6-only workloads). For example, the subnet containing the NAT gateway should have a `0.0.0.0/0` route pointing to the internet gateway. For more information, see [Configure DNS64 and NAT64](https://docs.aws.amazon.com/vpc/latest/userguide/nat-gateway-nat64-dns64.html#nat-gateway-nat64-dns64-walkthrough) in the *Amazon Virtual Private Cloud User Guide*.
*Required*: No  
*Type*: Boolean  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`EnableLniAtDeviceIndex`  <a name="cfn-ec2-subnet-enablelniatdeviceindex"></a>
 Indicates the device position for local network interfaces in this subnet. For example, `1` indicates local network interfaces in this subnet are the secondary network interface (eth1).   
*Required*: No  
*Type*: Integer  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`Ipv4IpamPoolId`  <a name="cfn-ec2-subnet-ipv4ipampoolid"></a>
An IPv4 IPAM pool ID for the subnet.  
*Required*: No  
*Type*: String  
*Update requires*: [Replacement](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-replacement)

`Ipv4NetmaskLength`  <a name="cfn-ec2-subnet-ipv4netmasklength"></a>
An IPv4 netmask length for the subnet.  
*Required*: No  
*Type*: Integer  
*Update requires*: [Replacement](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-replacement)

`Ipv6CidrBlock`  <a name="cfn-ec2-subnet-ipv6cidrblock"></a>
The IPv6 CIDR block.  
If you specify `AssignIpv6AddressOnCreation`, you must also specify an IPv6 CIDR block.  
*Required*: Conditional  
*Type*: String  
*Update requires*: [Some interruptions](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-some-interrupt)

`Ipv6IpamPoolId`  <a name="cfn-ec2-subnet-ipv6ipampoolid"></a>
An IPv6 IPAM pool ID for the subnet.  
*Required*: No  
*Type*: String  
*Update requires*: [Replacement](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-replacement)

`Ipv6Native`  <a name="cfn-ec2-subnet-ipv6native"></a>
Indicates whether this is an IPv6 only subnet. For more information, see [Subnet basics](https://docs.aws.amazon.com/vpc/latest/userguide/VPC_Subnets.html#subnet-basics) in the *Amazon Virtual Private Cloud User Guide*.  
*Required*: No  
*Type*: Boolean  
*Update requires*: [Replacement](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-replacement)

`Ipv6NetmaskLength`  <a name="cfn-ec2-subnet-ipv6netmasklength"></a>
An IPv6 netmask length for the subnet.  
*Required*: No  
*Type*: Integer  
*Update requires*: [Replacement](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-replacement)

`MapPublicIpOnLaunch`  <a name="cfn-ec2-subnet-mappubliciponlaunch"></a>
Indicates whether instances launched in this subnet receive a public IPv4 address. The default value is `false`.  
AWS charges for all public IPv4 addresses, including public IPv4 addresses associated with running instances and Elastic IP addresses. For more information, see the *Public IPv4 Address* tab on the [VPC pricing page](https://aws.amazon.com/vpc/pricing/).  
*Required*: No  
*Type*: Boolean  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`OutpostArn`  <a name="cfn-ec2-subnet-outpostarn"></a>
The Amazon Resource Name (ARN) of the Outpost.  
*Required*: No  
*Type*: String  
*Update requires*: [Replacement](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-replacement)

`PrivateDnsNameOptionsOnLaunch`  <a name="cfn-ec2-subnet-privatednsnameoptionsonlaunch"></a>
The hostname type for EC2 instances launched into this subnet and how DNS A and AAAA record queries to the instances should be handled. For more information, see [Amazon EC2 instance hostname types](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-instance-naming.html) in the *Amazon Elastic Compute Cloud User Guide*.  
Available options:  
+ EnableResourceNameDnsAAAARecord (true \$1 false)
+ EnableResourceNameDnsARecord (true \$1 false)
+ HostnameType (ip-name \$1 resource-name)
*Required*: No  
*Type*: [PrivateDnsNameOptionsOnLaunch](aws-properties-ec2-subnet-privatednsnameoptionsonlaunch.md)  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`Tags`  <a name="cfn-ec2-subnet-tags"></a>
Any tags assigned to the subnet.  
*Required*: No  
*Type*: Array of [Tag](aws-properties-ec2-subnet-tag.md)  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`VpcId`  <a name="cfn-ec2-subnet-vpcid"></a>
The ID of the VPC the subnet is in.  
If you update this property, you must also update the `CidrBlock` property.  
*Required*: Yes  
*Type*: String  
*Update requires*: [Replacement](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-replacement)

## Return values
<a name="aws-resource-ec2-subnet-return-values"></a>

### Ref
<a name="aws-resource-ec2-subnet-return-values-ref"></a>

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

For more information about using the `Ref` function, see [https://docs.aws.amazon.com/AWSCloudFormation/latest/TemplateReference/intrinsic-function-reference-ref.html](https://docs.aws.amazon.com/AWSCloudFormation/latest/TemplateReference/intrinsic-function-reference-ref.html).

### Fn::GetAtt
<a name="aws-resource-ec2-subnet-return-values-fn--getatt"></a>

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 [https://docs.aws.amazon.com/AWSCloudFormation/latest/TemplateReference/intrinsic-function-reference-getatt.html](https://docs.aws.amazon.com/AWSCloudFormation/latest/TemplateReference/intrinsic-function-reference-getatt.html).

#### 
<a name="aws-resource-ec2-subnet-return-values-fn--getatt-fn--getatt"></a>

`AvailabilityZone`  <a name="AvailabilityZone-fn::getatt"></a>
The Availability Zone of this subnet. For example, `us-east-1a`.

`AvailabilityZoneId`  <a name="AvailabilityZoneId-fn::getatt"></a>
The Availability Zone ID of this subnet. For example, `use1-az1`.

`CidrBlock`  <a name="CidrBlock-fn::getatt"></a>
The IPv4 CIDR blocks that are associated with the subnet.

`Ipv6CidrBlocks`  <a name="Ipv6CidrBlocks-fn::getatt"></a>
The IPv6 CIDR blocks that are associated with the subnet.

`NetworkAclAssociationId`  <a name="NetworkAclAssociationId-fn::getatt"></a>
The ID of the network ACL that is associated with the subnet's VPC, such as `acl-5fb85d36`.

`OutpostArn`  <a name="OutpostArn-fn::getatt"></a>
The Amazon Resource Name (ARN) of the Outpost.

`SubnetId`  <a name="SubnetId-fn::getatt"></a>
The ID of the subnet.

`VpcId`  <a name="VpcId-fn::getatt"></a>
The ID of the subnet's VPC, such as `vpc-11ad4878`.

## Examples
<a name="aws-resource-ec2-subnet--examples"></a>



**Topics**
+ [Subnet with an IPv4 CIDR](#aws-resource-ec2-subnet--examples--Subnet_with_an_IPv4_CIDR)
+ [Subnet with an IPv6 CIDR](#aws-resource-ec2-subnet--examples--Subnet_with_an_IPv6_CIDR)

### Subnet with an IPv4 CIDR
<a name="aws-resource-ec2-subnet--examples--Subnet_with_an_IPv4_CIDR"></a>

The following example creates a subnet with an IPv4 CIDR in a VPC with an IPv4 CIDR of 10.0.0.0/16. The VPC is declared elsewhere in the same template.

#### JSON
<a name="aws-resource-ec2-subnet--examples--Subnet_with_an_IPv4_CIDR--json"></a>

```
"mySubnet" : {
   "Type" : "AWS::EC2::Subnet",
   "Properties" : {
      "VpcId" : { "Ref" : "myVPC" },
      "CidrBlock" : "10.0.0.0/24",
      "AvailabilityZone" : "us-east-1a",
      "Tags" : [ { "Key" : "stack", "Value" : "production" } ]
   }
}
```

#### YAML
<a name="aws-resource-ec2-subnet--examples--Subnet_with_an_IPv4_CIDR--yaml"></a>

```
  mySubnet:
    Type: AWS::EC2::Subnet
    Properties:
      VpcId: !Ref myVPC
      CidrBlock: 10.0.0.0/24
      AvailabilityZone: "us-east-1a"
      Tags:
      - Key: stack
        Value: production
```

### Subnet with an IPv6 CIDR
<a name="aws-resource-ec2-subnet--examples--Subnet_with_an_IPv6_CIDR"></a>

The following example creates a subnet with an IPv6 CIDR in a VPC with an IPv6 CIDR provided by Amazon. The VPC is declared elsewhere in the same template. The example uses the [Fn:Cidr](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/intrinsic-function-reference-cidr.html) intrinsic function to select an IPv6 range with a /64 netmask for the subnet.

#### JSON
<a name="aws-resource-ec2-subnet--examples--Subnet_with_an_IPv6_CIDR--json"></a>

```
"mySubnet": {
   "Type": "AWS::EC2::Subnet",
   "Properties": {
      "VpcId": { "Ref": "myVPC" },
      "Ipv6Native": "true",
      "Ipv6CidrBlock": { 
         "Fn::Select": 
            [ 0, { "Fn::Cidr": [{"Fn::Select": [0, {"Fn::GetAtt": ["myVpc", "Ipv6CidrBlocks"]}]}, 1, 64 ]}]
      },
      "AssignIpv6AddressOnCreation": "true"
   }
}
```

#### YAML
<a name="aws-resource-ec2-subnet--examples--Subnet_with_an_IPv6_CIDR--yaml"></a>

```
  mySubnet:
    Type: AWS::EC2::Subnet
    Properties:
      VpcId: !Ref myVPC
      Ipv6Native: true
      Ipv6CidrBlock: !Select [ 0, !Cidr [ !Select [ 0, !GetAtt myVpc.Ipv6CidrBlocks], 1, 64 ]]
      AssignIpv6AddressOnCreation: true
```

## See also
<a name="aws-resource-ec2-subnet--seealso"></a>
+ [CreateSubnet](https://docs.aws.amazon.com/AWSEC2/latest/APIReference/API_CreateSubnet.html) in the *Amazon EC2 API Reference*
+ [VPC and subnets](https://docs.aws.amazon.com/vpc/latest/userguide/VPC_Subnets.html) in the *Amazon VPC User Guide*



# AWS::EC2::Subnet BlockPublicAccessStates
<a name="aws-properties-ec2-subnet-blockpublicaccessstates"></a>

Specifies the state of VPC Block Public Access (BPA).

## Syntax
<a name="aws-properties-ec2-subnet-blockpublicaccessstates-syntax"></a>

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

### JSON
<a name="aws-properties-ec2-subnet-blockpublicaccessstates-syntax.json"></a>

```
{
  "[InternetGatewayBlockMode](#cfn-ec2-subnet-blockpublicaccessstates-internetgatewayblockmode)" : String
}
```

### YAML
<a name="aws-properties-ec2-subnet-blockpublicaccessstates-syntax.yaml"></a>

```
  [InternetGatewayBlockMode](#cfn-ec2-subnet-blockpublicaccessstates-internetgatewayblockmode): String
```

## Properties
<a name="aws-properties-ec2-subnet-blockpublicaccessstates-properties"></a>

`InternetGatewayBlockMode`  <a name="cfn-ec2-subnet-blockpublicaccessstates-internetgatewayblockmode"></a>
The mode of VPC BPA.  
+ `off`: VPC BPA is not enabled and traffic is allowed to and from internet gateways and egress-only internet gateways in this Region.
+ `block-bidirectional`: Block all traffic to and from internet gateways and egress-only internet gateways in this Region (except for excluded VPCs and subnets).
+ `block-ingress`: Block all internet traffic to the VPCs in this Region (except for VPCs or subnets which are excluded). Only traffic to and from NAT gateways and egress-only internet gateways is allowed because these gateways only allow outbound connections to be established.
*Required*: No  
*Type*: String  
*Allowed values*: `off | block-bidirectional | block-ingress`  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

# AWS::EC2::Subnet PrivateDnsNameOptionsOnLaunch
<a name="aws-properties-ec2-subnet-privatednsnameoptionsonlaunch"></a>

Specifies the options for instance hostnames.

## Syntax
<a name="aws-properties-ec2-subnet-privatednsnameoptionsonlaunch-syntax"></a>

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

### JSON
<a name="aws-properties-ec2-subnet-privatednsnameoptionsonlaunch-syntax.json"></a>

```
{
  "[EnableResourceNameDnsAAAARecord](#cfn-ec2-subnet-privatednsnameoptionsonlaunch-enableresourcenamednsaaaarecord)" : Boolean,
  "[EnableResourceNameDnsARecord](#cfn-ec2-subnet-privatednsnameoptionsonlaunch-enableresourcenamednsarecord)" : Boolean,
  "[HostnameType](#cfn-ec2-subnet-privatednsnameoptionsonlaunch-hostnametype)" : String
}
```

### YAML
<a name="aws-properties-ec2-subnet-privatednsnameoptionsonlaunch-syntax.yaml"></a>

```
  [EnableResourceNameDnsAAAARecord](#cfn-ec2-subnet-privatednsnameoptionsonlaunch-enableresourcenamednsaaaarecord): Boolean
  [EnableResourceNameDnsARecord](#cfn-ec2-subnet-privatednsnameoptionsonlaunch-enableresourcenamednsarecord): Boolean
  [HostnameType](#cfn-ec2-subnet-privatednsnameoptionsonlaunch-hostnametype): String
```

## Properties
<a name="aws-properties-ec2-subnet-privatednsnameoptionsonlaunch-properties"></a>

`EnableResourceNameDnsAAAARecord`  <a name="cfn-ec2-subnet-privatednsnameoptionsonlaunch-enableresourcenamednsaaaarecord"></a>
Indicates whether to respond to DNS queries for instance hostname with DNS AAAA records.  
*Required*: No  
*Type*: Boolean  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`EnableResourceNameDnsARecord`  <a name="cfn-ec2-subnet-privatednsnameoptionsonlaunch-enableresourcenamednsarecord"></a>
Indicates whether to respond to DNS queries for instance hostnames with DNS A records.  
*Required*: No  
*Type*: Boolean  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`HostnameType`  <a name="cfn-ec2-subnet-privatednsnameoptionsonlaunch-hostnametype"></a>
The type of hostname for EC2 instances. For IPv4 only subnets, an instance DNS name must be based on the instance IPv4 address. For IPv6 only subnets, an instance DNS name must be based on the instance ID. For dual-stack subnets, you can specify whether DNS names use the instance IPv4 address or the instance ID.  
*Required*: No  
*Type*: String  
*Allowed values*: `ip-name | resource-name`  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

# AWS::EC2::Subnet Tag
<a name="aws-properties-ec2-subnet-tag"></a>

Specifies a tag. For more information, see [Resource tags](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-resource-tags.html).

## Syntax
<a name="aws-properties-ec2-subnet-tag-syntax"></a>

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

### JSON
<a name="aws-properties-ec2-subnet-tag-syntax.json"></a>

```
{
  "[Key](#cfn-ec2-subnet-tag-key)" : String,
  "[Value](#cfn-ec2-subnet-tag-value)" : String
}
```

### YAML
<a name="aws-properties-ec2-subnet-tag-syntax.yaml"></a>

```
  [Key](#cfn-ec2-subnet-tag-key): String
  [Value](#cfn-ec2-subnet-tag-value): String
```

## Properties
<a name="aws-properties-ec2-subnet-tag-properties"></a>

`Key`  <a name="cfn-ec2-subnet-tag-key"></a>
The tag key.  
*Required*: Yes  
*Type*: String  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`Value`  <a name="cfn-ec2-subnet-tag-value"></a>
The tag value.  
*Required*: Yes  
*Type*: String  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

## Examples
<a name="aws-properties-ec2-subnet-tag--examples"></a>

### 
<a name="aws-properties-ec2-subnet-tag--examples--"></a>

This example specifies two tags for the subnet.

#### JSON
<a name="aws-properties-ec2-subnet-tag--examples----json"></a>

```
"Tags" : [
   {
      "Key" : "key1",
      "Value" : "value1"
   },
   {
      "Key" : "key2",
      "Value" : "value2"
   }
]
```

#### YAML
<a name="aws-properties-ec2-subnet-tag--examples----yaml"></a>

```
Tags: 
  - Key: "key1"
    Value: "value1"
  - Key: "key2"
    Value: "value2"
```