# DnsRecordProperty

A complex type that contains information about the Route 53 DNS records that you want AWS Cloud Map to create when you register an instance.

- Source: Generated code
- Type last changed: v2.93.0 · 23 Aug 2023

## Example

```ts
// The code below shows an example of how to instantiate this type.
// The values are placeholders you should change.
import { aws_servicediscovery as servicediscovery } from 'aws-cdk-lib';
const dnsRecordProperty: servicediscovery.CfnService.DnsRecordProperty = {
  ttl: 123,
  type: 'type',
};
```

## Properties

- `ttl`: number (required) — The amount of time, in seconds, that you want DNS resolvers to cache the settings for this record.

  > Alias records don't include a TTL because Route 53 uses the TTL for the AWS resource that an alias record routes traffic to. If you include the `AWS_ALIAS_DNS_NAME` attribute when you submit a [RegisterInstance](https://docs.aws.amazon.com/cloud-map/latest/api/API_RegisterInstance.html) request, the `TTL` value is ignored. Always specify a TTL for the service; you can use a service to register instances that create either alias or non-alias records.

- `type`: string (required) — The type of the resource, which indicates the type of value that Route 53 returns in response to DNS queries.

  You can specify values for `Type` in the following combinations:

  - `A`
  - `AAAA`
  - `A` and `AAAA`
  - `SRV`
  - `CNAME`

  If you want AWS Cloud Map to create a Route 53 alias record when you register an instance, specify `A` or `AAAA` for `Type` .

  You specify other settings, such as the IP address for `A` and `AAAA` records, when you register an instance. For more information, see [RegisterInstance](https://docs.aws.amazon.com/cloud-map/latest/api/API_RegisterInstance.html) .

  The following values are supported:

  - **A** - Route 53 returns the IP address of the resource in IPv4 format, such as 192.0.2.44.
  - **AAAA** - Route 53 returns the IP address of the resource in IPv6 format, such as 2001:0db8:85a3:0000:0000:abcd:0001:2345.
  - **CNAME** - Route 53 returns the domain name of the resource, such as www.example.com. Note the following:

  - You specify the domain name that you want to route traffic to when you register an instance. For more information, see [Attributes](https://docs.aws.amazon.com/cloud-map/latest/api/API_RegisterInstance.html#cloudmap-RegisterInstance-request-Attributes) in the topic [RegisterInstance](https://docs.aws.amazon.com/cloud-map/latest/api/API_RegisterInstance.html) .
  - You must specify `WEIGHTED` for the value of `RoutingPolicy` .
  - You can't specify both `CNAME` for `Type` and settings for `HealthCheckConfig` . If you do, the request will fail with an `InvalidInput` error.
  - **SRV** - Route 53 returns the value for an `SRV` record. The value for an `SRV` record uses the following values:

  `priority weight port service-hostname`

  Note the following about the values:

  - The values of `priority` and `weight` are both set to `1` and can't be changed.
  - The value of `port` comes from the value that you specify for the `AWS_INSTANCE_PORT` attribute when you submit a [RegisterInstance](https://docs.aws.amazon.com/cloud-map/latest/api/API_RegisterInstance.html) request.
  - The value of `service-hostname` is a concatenation of the following values:

  - The value that you specify for `InstanceId` when you register an instance.
  - The name of the service.
  - The name of the namespace.

  For example, if the value of `InstanceId` is `test` , the name of the service is `backend` , and the name of the namespace is `example.com` , the value of `service-hostname` is:

  `test.backend.example.com`

  If you specify settings for an `SRV` record and if you specify values for `AWS_INSTANCE_IPV4` , `AWS_INSTANCE_IPV6` , or both in the `RegisterInstance` request, AWS Cloud Map automatically creates `A` and/or `AAAA` records that have the same name as the value of `service-hostname` in the `SRV` record. You can ignore these records.