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::ServiceDiscovery::Instance
<a name="aws-resource-servicediscovery-instance"></a>

A complex type that contains information about an instance that AWS Cloud Map creates when you submit a `RegisterInstance` request.

## Syntax
<a name="aws-resource-servicediscovery-instance-syntax"></a>

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

### JSON
<a name="aws-resource-servicediscovery-instance-syntax.json"></a>

```
{
  "Type" : "AWS::ServiceDiscovery::Instance",
  "Properties" : {
      "[InstanceAttributes](#cfn-servicediscovery-instance-instanceattributes)" : Json,
      "[InstanceId](#cfn-servicediscovery-instance-instanceid)" : String,
      "[ServiceId](#cfn-servicediscovery-instance-serviceid)" : String
    }
}
```

### YAML
<a name="aws-resource-servicediscovery-instance-syntax.yaml"></a>

```
Type: AWS::ServiceDiscovery::Instance
Properties:
  [InstanceAttributes](#cfn-servicediscovery-instance-instanceattributes): Json
  [InstanceId](#cfn-servicediscovery-instance-instanceid): String
  [ServiceId](#cfn-servicediscovery-instance-serviceid): String
```

## Properties
<a name="aws-resource-servicediscovery-instance-properties"></a>

`InstanceAttributes`  <a name="cfn-servicediscovery-instance-instanceattributes"></a>
A string map that contains the following information for the service that you specify in `ServiceId`:  
+ The attributes that apply to the records that are defined in the service. 
+ For each attribute, the applicable value.
Supported attribute keys include the following:    
AWS\$1ALIAS\$1DNS\$1NAME  
If you want AWS Cloud Map to create a Route 53 alias record that routes traffic to an Elastic Load Balancing load balancer, specify the DNS name that is associated with the load balancer. For information about how to get the DNS name, see [AliasTarget->DNSName](https://docs.aws.amazon.com/Route53/latest/APIReference/API_AliasTarget.html#Route53-Type-AliasTarget-DNSName) in the *Route 53 API Reference*.  
Note the following:  
+ The configuration for the service that is specified by `ServiceId` must include settings for an `A` record, an `AAAA` record, or both.
+ In the service that is specified by `ServiceId`, the value of `RoutingPolicy` must be `WEIGHTED`.
+ If the service that is specified by `ServiceId` includes `HealthCheckConfig` settings, AWS Cloud Map will create the health check, but it won't associate the health check with the alias record.
+ Auto naming currently doesn't support creating alias records that route traffic to AWS resources other than ELB load balancers.
+ If you specify a value for `AWS_ALIAS_DNS_NAME`, don't specify values for any of the `AWS_INSTANCE` attributes.  
AWS\$1EC2\$1INSTANCE\$1ID  
*HTTP namespaces only.* The Amazon EC2 instance ID for the instance. The `AWS_INSTANCE_IPV4` attribute contains the primary private IPv4 address. When creating resources with a type of [AWS::ServiceDiscovery::Instance](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-servicediscovery-instance.html), if the `AWS_EC2_INSTANCE_ID` attribute is specified, the only other attribute that can be specified is `AWS_INIT_HEALTH_STATUS`. After the resource has been created, the `AWS_INSTANCE_IPV4` attribute contains the primary private IPv4 address.  
AWS\$1INIT\$1HEALTH\$1STATUS  
If the service configuration includes `HealthCheckCustomConfig`, when creating resources with a type of [AWS::ServiceDiscovery::Instance](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-servicediscovery-instance.html) you can optionally use `AWS_INIT_HEALTH_STATUS` to specify the initial status of the custom health check, `HEALTHY` or `UNHEALTHY`. If you don't specify a value for `AWS_INIT_HEALTH_STATUS`, the initial status is `HEALTHY`. This attribute can only be used when creating resources and will not be seen on existing resources.  
AWS\$1INSTANCE\$1CNAME  
If the service configuration includes a `CNAME` record, the domain name that you want Route 53 to return in response to DNS queries, for example, `example.com`.  
This value is required if the service specified by `ServiceId` includes settings for an `CNAME` record.  
AWS\$1INSTANCE\$1IPV4  
If the service configuration includes an `A` record, the IPv4 address that you want Route 53 to return in response to DNS queries, for example, `192.0.2.44`.  
This value is required if the service specified by `ServiceId` includes settings for an `A` record. If the service includes settings for an `SRV` record, you must specify a value for `AWS_INSTANCE_IPV4`, `AWS_INSTANCE_IPV6`, or both.  
AWS\$1INSTANCE\$1IPV6  
If the service configuration includes an `AAAA` record, the IPv6 address that you want Route 53 to return in response to DNS queries, for example, `2001:0db8:85a3:0000:0000:abcd:0001:2345`.  
This value is required if the service specified by `ServiceId` includes settings for an `AAAA` record. If the service includes settings for an `SRV` record, you must specify a value for `AWS_INSTANCE_IPV4`, `AWS_INSTANCE_IPV6`, or both.  
AWS\$1INSTANCE\$1PORT  
If the service includes an `SRV` record, the value that you want Route 53 to return for the port.  
If the service includes `HealthCheckConfig`, the port on the endpoint that you want Route 53 to send requests to.   
This value is required if you specified settings for an `SRV` record or a Route 53 health check when you created the service.
*Required*: Yes  
*Type*: Json  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`InstanceId`  <a name="cfn-servicediscovery-instance-instanceid"></a>
An identifier that you want to associate with the instance. Note the following:  
+ If the service that's specified by `ServiceId` includes settings for an `SRV` record, the value of `InstanceId` is automatically included as part of the value for the `SRV` record. For more information, see [DnsRecord > Type](https://docs.aws.amazon.com/cloud-map/latest/api/API_DnsRecord.html#cloudmap-Type-DnsRecord-Type).
+ You can use this value to update an existing instance.
+ To register a new instance, you must specify a value that's unique among instances that you register by using the same service. 
+ If you specify an existing `InstanceId` and `ServiceId`, AWS Cloud Map updates the existing DNS records, if any. If there's also an existing health check, AWS Cloud Map deletes the old health check and creates a new one. 
**Note**  
The health check isn't deleted immediately, so it will still appear for a while if you submit a `ListHealthChecks` request, for example.
Do not include sensitive information in `InstanceId` if the namespace is discoverable by public DNS queries and any `Type` member of `DnsRecord` for the service contains `SRV` because the `InstanceId` is discoverable by public DNS queries.
*Required*: No  
*Type*: String  
*Pattern*: `^[0-9a-zA-Z_/:.@-]+$`  
*Maximum*: `64`  
*Update requires*: [Replacement](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-replacement)

`ServiceId`  <a name="cfn-servicediscovery-instance-serviceid"></a>
The ID or Amazon Resource Name (ARN) of the service that you want to use for settings for the instance. For services created in a shared namespace, specify the service ARN. For more information about shared namespaces, see [Cross-account AWS Cloud Map namespace sharing](https://docs.aws.amazon.com/cloud-map/latest/dg/sharing-namespaces.html) in the *AWS Cloud Map Developer Guide*.  
*Required*: Yes  
*Type*: String  
*Maximum*: `255`  
*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-servicediscovery-instance-return-values"></a>

### Ref
<a name="aws-resource-servicediscovery-instance-return-values-ref"></a>

When you pass the logical ID of this resource to the intrinsic `Ref` function, `Ref` returns the value of `Id` for the instance, such as `i-abcd1234`.

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-servicediscovery-instance-return-values-fn--getatt"></a>

#### 
<a name="aws-resource-servicediscovery-instance-return-values-fn--getatt-fn--getatt"></a>

`InstanceId`  <a name="InstanceId-fn::getatt"></a>
The ID of an instance that matches the values that you specified in the request.

## Examples
<a name="aws-resource-servicediscovery-instance--examples"></a>



**Topics**
+ [Use custom attributes to register resources](#aws-resource-servicediscovery-instance--examples--Use_custom_attributes_to_register_resources)
+ [Provide IP addresses for an instance](#aws-resource-servicediscovery-instance--examples--Provide_IP_addresses_for_an_instance)

### Use custom attributes to register resources
<a name="aws-resource-servicediscovery-instance--examples--Use_custom_attributes_to_register_resources"></a>

The following example registers application resources like a DynamoDB table and Lambda functions as instances using the table and function names as custom attributes. The Lambda functions also have an `action` custom attribute used to distinguish the read function from the write function. The DynamoDB table is registered using the service that has the ID `srv-e3anhexample0003`. The read and write Lambda functions are registered using the service that has the ID `srv-e4anhexample0004`. This example is based on the tutorial [Learn how to use AWS Cloud Map service discovery with custom attributes](https://docs.aws.amazon.com/cloud-map/latest/dg/tutorial-private-namespace.html) in the *AWS Cloud Map Developer Guide*.

#### JSON
<a name="aws-resource-servicediscovery-instance--examples--Use_custom_attributes_to_register_resources--json"></a>

```
{
  "Resources": {
    "ReadInstance": {
      "Type": "AWS::ServiceDiscovery::Instance",
      "Properties": {
        "InstanceAttributes": {
          "functionname": "readfunction",
          "action": "read"
        },
        "InstanceId": "read-instance",
        "ServiceId": "srv-e4anhexample0004"
      }
    },
    "WriteInstance": {
      "Type": "AWS::ServiceDiscovery::Instance",
      "Properties": {
        "InstanceAttributes": {
          "functionname": "writefunction",
          "action": "write"
        },
        "InstanceId": "write-instance",
        "ServiceId": "srv-e4anhexample0004"
      }
    },
    "DataInstance": {
      "Type": "AWS::ServiceDiscovery::Instance",
      "Properties": {
        "InstanceAttributes": {
          "tablename": "cloudmap"
        },
        "InstanceId": "data-instance",
        "ServiceId": "srv-e3anhexample0003"
      }
    }
  }
}
```

#### YAML
<a name="aws-resource-servicediscovery-instance--examples--Use_custom_attributes_to_register_resources--yaml"></a>

```
Resources:
  ReadInstance:
    Type: AWS::ServiceDiscovery::Instance
    Properties:
      InstanceAttributes:
        functionname: readfunction
        action: read
      InstanceId: read-instance   
      ServiceId: srv-e4anhexample0004
  WriteInstance:
    Type: AWS::ServiceDiscovery::Instance
    Properties:
      InstanceAttributes:
        functionname: writefunction
        action: write
      InstanceId: write-instance 
      ServiceId: srv-e4anhexample0004
  DataInstance:
    Type: AWS::ServiceDiscovery::Instance
    Properties:
      InstanceAttributes:
        tablename: cloudmap
      InstanceId: data-instance  
      ServiceId: srv-e3anhexample0003
```

### Provide IP addresses for an instance
<a name="aws-resource-servicediscovery-instance--examples--Provide_IP_addresses_for_an_instance"></a>

The following example provides IPv4 and IPV6 IP addresses for the instance that has an ID of `i-abcd1234`. The instance was registered using the service that has an ID of `srv-e4anhexample0004`.

#### JSON
<a name="aws-resource-servicediscovery-instance--examples--Provide_IP_addresses_for_an_instance--json"></a>

```
{
    "Resources": {
        "Instance": {
            "Type": "AWS::ServiceDiscovery::Instance",
            "Properties": {
                "InstanceAttributes": {
                    "AWS_INSTANCE_IPV4": "192.0.2.44",
                    "AWS_INSTANCE_IPV6": "2001:0db8:85a3:0000:0000:abcd:0001:2345"
                },
                "InstanceId": "i-abcd1234",
                "ServiceId": "srv-e4anhexample0004"
            }
        }
    }
}
```

#### YAML
<a name="aws-resource-servicediscovery-instance--examples--Provide_IP_addresses_for_an_instance--yaml"></a>

```
Resources:
  Instance:
    Type: AWS::ServiceDiscovery::Instance
    Properties:
      InstanceAttributes:
        AWS_INSTANCE_IPV4: 192.0.2.44
        AWS_INSTANCE_IPV6: 2001:0db8:85a3:0000:0000:abcd:0001:2345
      InstanceId: i-abcd1234
      ServiceId: srv-e4anhexample0004
```

## See also
<a name="aws-resource-servicediscovery-instance--seealso"></a>
+ [RegisterInstance](https://docs.aws.amazon.com/cloud-map/latest/api/API_RegisterInstance.html) in the * AWS Cloud Map API Reference *