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Amazon Route 53
API Reference

AliasTarget

Alias resource record sets only: Information about the CloudFront distribution, Elastic Beanstalk environment, ELB load balancer, Amazon S3 bucket, or Amazon Route 53 resource record set that you're redirecting queries to. An Elastic Beanstalk environment must have a regionalized subdomain.

When creating resource record sets for a private hosted zone, note the following:

  • Resource record sets can't be created for CloudFront distributions in a private hosted zone.

  • Creating geolocation alias resource record sets or latency alias resource record sets in a private hosted zone is unsupported.

  • For information about creating failover resource record sets in a private hosted zone, see Configuring Failover in a Private Hosted Zone.

Contents

DNSName

Alias resource record sets only: The value that you specify depends on where you want to route queries:

CloudFront distribution

Specify the domain name that CloudFront assigned when you created your distribution.

Your CloudFront distribution must include an alternate domain name that matches the name of the resource record set. For example, if the name of the resource record set is acme.example.com, your CloudFront distribution must include acme.example.com as one of the alternate domain names. For more information, see Using Alternate Domain Names (CNAMEs) in the Amazon CloudFront Developer Guide.

Note

For failover alias records, you can't specify a CloudFront distribution for both the primary and secondary records. A distribution must include an alternate domain name that matches the name of the record. However, the primary and secondary records have the same name, and you can't include the same alternate domain name in more than one distribution.

Elastic Beanstalk environment

If the domain name for your Elastic Beanstalk environment includes the region that you deployed the environment in, you can create an alias record that routes traffic to the environment. For example, the domain name my-environment.us-west-2.elasticbeanstalk.com is a regionalized domain name.

Important

For environments that were created before early 2016, the domain name doesn't include the region. To route traffic to these environments, you must create a CNAME record instead of an alias record. Note that you can't create a CNAME record for the root domain name. For example, if your domain name is example.com, you can create a record that routes traffic for acme.example.com to your Elastic Beanstalk environment, but you can't create a record that routes traffic for example.com to your Elastic Beanstalk environment.

For Elastic Beanstalk environments that have regionalized subdomains, specify the CNAME attribute for the environment. You can use the following methods to get the value of the CNAME attribute:

  • AWS Management Console: For information about how to get the value by using the console, see Using Custom Domains with AWS Elastic Beanstalk in the AWS Elastic Beanstalk Developer Guide.

  • Elastic Beanstalk API: Use the DescribeEnvironments action to get the value of the CNAME attribute. For more information, see DescribeEnvironments in the AWS Elastic Beanstalk API Reference.

  • AWS CLI: Use the describe-environments command to get the value of the CNAME attribute. For more information, see describe-environments in the AWS Command Line Interface Reference.

ELB load balancer

Specify the DNS name that is associated with the load balancer. Get the DNS name by using the AWS Management Console, the ELB API, or the AWS CLI.

  • AWS Management Console: Go to the EC2 page, choose Load Balancers in the navigation pane, choose the load balancer, choose the Description tab, and get the value of the DNS name field. (If you're routing traffic to a Classic Load Balancer, get the value that begins with dualstack.)

  • Elastic Load Balancing API: Use DescribeLoadBalancers to get the value of DNSName. For more information, see the applicable guide:

  • AWS CLI: Use describe-load-balancers to get the value of DNSName. For more information, see the applicable guide:

Amazon S3 bucket that is configured as a static website

Specify the domain name of the Amazon S3 website endpoint that you created the bucket in, for example, s3-website-us-east-2.amazonaws.com. For more information about valid values, see the table Amazon Simple Storage Service (S3) Website Endpoints in the Amazon Web Services General Reference. For more information about using S3 buckets for websites, see Getting Started with Amazon Route 53 in the Amazon Route 53 Developer Guide.

Another Route 53 resource record set

Specify the value of the Name element for a resource record set in the current hosted zone.

Note

If you're creating an alias record that has the same name as the hosted zone (known as the zone apex), you can't specify the domain name for a record for which the value of Type is CNAME. This is because the alias record must have the same type as the record that you're routing traffic to, and creating a CNAME record for the zone apex isn't supported even for an alias record.

Type: String

Length Constraints: Maximum length of 1024.

Required: Yes

EvaluateTargetHealth

Applies only to alias, failover alias, geolocation alias, latency alias, and weighted alias resource record sets: When EvaluateTargetHealth is true, an alias resource record set inherits the health of the referenced AWS resource, such as an ELB load balancer or another resource record set in the hosted zone.

Note the following:

CloudFront distributions

You can't set EvaluateTargetHealth to true when the alias target is a CloudFront distribution.

Elastic Beanstalk environments that have regionalized subdomains

If you specify an Elastic Beanstalk environment in DNSName and the environment contains an ELB load balancer, Elastic Load Balancing routes queries only to the healthy Amazon EC2 instances that are registered with the load balancer. (An environment automatically contains an ELB load balancer if it includes more than one Amazon EC2 instance.) If you set EvaluateTargetHealth to true and either no Amazon EC2 instances are healthy or the load balancer itself is unhealthy, Route 53 routes queries to other available resources that are healthy, if any.

If the environment contains a single Amazon EC2 instance, there are no special requirements.

ELB load balancers

Health checking behavior depends on the type of load balancer:

  • Classic Load Balancers: If you specify an ELB Classic Load Balancer in DNSName, Elastic Load Balancing routes queries only to the healthy Amazon EC2 instances that are registered with the load balancer. If you set EvaluateTargetHealth to true and either no EC2 instances are healthy or the load balancer itself is unhealthy, Route 53 routes queries to other resources.

  • Application and Network Load Balancers: If you specify an ELB Application or Network Load Balancer and you set EvaluateTargetHealth to true, Route 53 routes queries to the load balancer based on the health of the target groups that are associated with the load balancer:

    • For an Application or Network Load Balancer to be considered healthy, every target group that contains targets must contain at least one healthy target. If any target group contains only unhealthy targets, the load balancer is considered unhealthy, and Route 53 routes queries to other resources.

    • A target group that has no registered targets is considered healthy.

Note

When you create a load balancer, you configure settings for Elastic Load Balancing health checks; they're not Route 53 health checks, but they perform a similar function. Do not create Route 53 health checks for the EC2 instances that you register with an ELB load balancer.

S3 buckets

There are no special requirements for setting EvaluateTargetHealth to true when the alias target is an S3 bucket.

Other records in the same hosted zone

If the AWS resource that you specify in DNSName is a record or a group of records (for example, a group of weighted records) but is not another alias record, we recommend that you associate a health check with all of the records in the alias target. For more information, see What Happens When You Omit Health Checks? in the Amazon Route 53 Developer Guide.

For more information and examples, see Amazon Route 53 Health Checks and DNS Failover in the Amazon Route 53 Developer Guide.

Type: Boolean

Required: Yes

HostedZoneId

Alias resource records sets only: The value used depends on where you want to route traffic:

CloudFront distribution

Specify Z2FDTNDATAQYW2.

Note

Alias resource record sets for CloudFront can't be created in a private zone.

Elastic Beanstalk environment

Specify the hosted zone ID for the region that you created the environment in. The environment must have a regionalized subdomain. For a list of regions and the corresponding hosted zone IDs, see AWS Elastic Beanstalk in the "AWS Regions and Endpoints" chapter of the Amazon Web Services General Reference.

ELB load balancer

Specify the value of the hosted zone ID for the load balancer. Use the following methods to get the hosted zone ID:

  • Elastic Load Balancing table in the "AWS Regions and Endpoints" chapter of the Amazon Web Services General Reference: Use the value that corresponds with the region that you created your load balancer in. Note that there are separate columns for Application and Classic Load Balancers and for Network Load Balancers.

  • AWS Management Console: Go to the Amazon EC2 page, choose Load Balancers in the navigation pane, select the load balancer, and get the value of the Hosted zone field on the Description tab.

  • Elastic Load Balancing API: Use DescribeLoadBalancers to get the applicable value. For more information, see the applicable guide:

  • AWS CLI: Use describe-load-balancers to get the applicable value. For more information, see the applicable guide:

An Amazon S3 bucket configured as a static website

Specify the hosted zone ID for the region that you created the bucket in. For more information about valid values, see the Amazon Simple Storage Service Website Endpoints table in the "AWS Regions and Endpoints" chapter of the Amazon Web Services General Reference.

Another Route 53 resource record set in your hosted zone

Specify the hosted zone ID of your hosted zone. (An alias resource record set can't reference a resource record set in a different hosted zone.)

Type: String

Length Constraints: Maximum length of 32.

Required: Yes

See Also

For more information about using this API in one of the language-specific AWS SDKs, see the following:

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