A distribution configuration.

If you want CloudFront to respond to IPv6 DNS requests with an IPv6 address for your distribution, specify true. If you specify false, CloudFront responds to IPv6 DNS requests with the DNS response code NOERROR and with no IP addresses. This allows viewers to submit a second request, for an IPv4 address for your distribution.

In general, you should enable IPv6 if you have users on IPv6 networks who want to access your content. However, if you're using signed URLs or signed cookies to restrict access to your content, and if you're using a custom policy that includes the IpAddress parameter to restrict the IP addresses that can access your content, don't enable IPv6. If you want to restrict access to some content by IP address and not restrict access to other content (or restrict access but not by IP address), you can create two distributions. For more information, see Creating a Signed URL Using a Custom Policy in the Amazon CloudFront Developer Guide.

If you're using an Amazon Route 53 alias resource record set to route traffic to your CloudFront distribution, you need to create a second alias resource record set when both of the following are true:

• You enable IPv6 for the distribution

• You're using alternate domain names in the URLs for your objects

For more information, see Routing Traffic to an Amazon CloudFront Web Distribution by Using Your Domain Name in the Amazon Route 53 Developer Guide.

If you created a CNAME resource record set, either with Amazon Route 53 or with another DNS service, you don't need to make any changes. A CNAME record will route traffic to your distribution regardless of the IP address format of the viewer request.

(Optional) Specify the maximum HTTP version that you want viewers to use to communicate with CloudFront. The default value for new web distributions is http2. Viewers that don't support HTTP/2 automatically use an earlier HTTP version.

For viewers and CloudFront to use HTTP/2, viewers must support TLS 1.2 or later, and must support Server Name Identification (SNI).

In general, configuring CloudFront to communicate with viewers using HTTP/2 reduces latency. You can improve performance by optimizing for HTTP/2. For more information, do an Internet search for "http/2 optimization."

A unique identifier that specifies the AWS WAF web ACL, if any, to associate with this distribution.

AWS WAF is a web application firewall that lets you monitor the HTTP and HTTPS requests that are forwarded to CloudFront, and lets you control access to your content. Based on conditions that you specify, such as the IP addresses that requests originate from or the values of query strings, CloudFront responds to requests either with the requested content or with an HTTP 403 status code (Forbidden). You can also configure CloudFront to return a custom error page when a request is blocked. For more information about AWS WAF, see the AWS WAF Developer Guide.

From this field, you can enable or disable the selected distribution.

The price class that corresponds with the maximum price that you want to pay for CloudFront service. If you specify PriceClass_All, CloudFront responds to requests for your objects from all CloudFront edge locations.

If you specify a price class other than PriceClass_All, CloudFront serves your objects from the CloudFront edge location that has the lowest latency among the edge locations in your price class. Viewers who are in or near regions that are excluded from your specified price class may encounter slower performance.

For more information about price classes, see Choosing the Price Class for a CloudFront Distribution in the Amazon CloudFront Developer Guide. For information about CloudFront pricing, including how price classes (such as Price Class 100) map to CloudFront regions, see Amazon CloudFront Pricing. For price class information, scroll down to see the table at the bottom of the page.

A complex type that controls whether access logs are written for the distribution.

For more information about logging, see Access Logs in the Amazon CloudFront Developer Guide.

Any comments you want to include about the distribution.

If you don't want to specify a comment, include an empty Comment element.

To delete an existing comment, update the distribution configuration and include an empty Comment element.

To add or change a comment, update the distribution configuration and specify the new comment.

A complex type that controls the following:

• Whether CloudFront replaces HTTP status codes in the 4xx and 5xx range with custom error messages before returning the response to the viewer.

• How long CloudFront caches HTTP status codes in the 4xx and 5xx range.

For more information about custom error pages, see Customizing Error Responses in the Amazon CloudFront Developer Guide.

A complex type that contains zero or more CacheBehavior elements.

A complex type that describes the default cache behavior if you don't specify a CacheBehavior element or if files don't match any of the values of PathPattern in CacheBehavior elements. You must create exactly one default cache behavior.

A complex type that contains information about origin groups for this distribution.

A complex type that contains information about origins for this distribution.

The object that you want CloudFront to request from your origin (for example, index.html) when a viewer requests the root URL for your distribution (http://www.example.com) instead of an object in your distribution (http://www.example.com/product-description.html). Specifying a default root object avoids exposing the contents of your distribution.

Specify only the object name, for example, index.html. Don't add a / before the object name.

If you don't want to specify a default root object when you create a distribution, include an empty DefaultRootObject element.

To delete the default root object from an existing distribution, update the distribution configuration and include an empty DefaultRootObject element.

To replace the default root object, update the distribution configuration and specify the new object.

For more information about the default root object, see Creating a Default Root Object in the Amazon CloudFront Developer Guide.

A complex type that contains information about CNAMEs (alternate domain names), if any, for this distribution.

A unique value (for example, a date-time stamp) that ensures that the request can't be replayed.

If the value of CallerReference is new (regardless of the content of the DistributionConfig object), CloudFront creates a new distribution.

If CallerReference is a value that you already sent in a previous request to create a distribution, CloudFront returns a DistributionAlreadyExists error.

A complex type that lists the AWS accounts, if any, that you included in the TrustedSigners complex type for this distribution. These are the accounts that you want to allow to create signed URLs for private content.

The Signer complex type lists the AWS account number of the trusted signer or self if the signer is the AWS account that created the distribution. The Signer element also includes the IDs of any active CloudFront key pairs that are associated with the trusted signer's AWS account. If no KeyPairId element appears for a Signer, that signer can't create signed URLs.

For more information, see Serving Private Content through CloudFront in the Amazon CloudFront Developer Guide.

A complex type that contains one Signer complex type for each trusted signer that is specified in the TrustedSigners complex type.

For more information, see ActiveTrustedSigners.

A complex type that contains one Signer complex type for each trusted signer specified in the TrustedSigners complex type.

For more information, see ActiveTrustedSigners.

Enabled is true if any of the AWS accounts listed in the TrustedSigners complex type for this RTMP distribution have active CloudFront key pairs. If not, Enabled is false.

For more information, see ActiveTrustedSigners.

An invalidation batch.

A value that you specify to uniquely identify an invalidation request. CloudFront uses the value to prevent you from accidentally resubmitting an identical request. Whenever you create a new invalidation request, you must specify a new value for CallerReference and change other values in the request as applicable. One way to ensure that the value of CallerReference is unique is to use a timestamp, for example, 20120301090000.

If you make a second invalidation request with the same value for CallerReference, and if the rest of the request is the same, CloudFront doesn't create a new invalidation request. Instead, CloudFront returns information about the invalidation request that you previously created with the same CallerReference.

If CallerReference is a value you already sent in a previous invalidation batch request but the content of any Path is different from the original request, CloudFront returns an InvalidationBatchAlreadyExists error.

A complex type that contains information about the objects that you want to invalidate. For more information, see Specifying the Objects to Invalidate in the Amazon CloudFront Developer Guide.

An invalidation batch.

A value that you specify to uniquely identify an invalidation request. CloudFront uses the value to prevent you from accidentally resubmitting an identical request. Whenever you create a new invalidation request, you must specify a new value for CallerReference and change other values in the request as applicable. One way to ensure that the value of CallerReference is unique is to use a timestamp, for example, 20120301090000.

If you make a second invalidation request with the same value for CallerReference, and if the rest of the request is the same, CloudFront doesn't create a new invalidation request. Instead, CloudFront returns information about the invalidation request that you previously created with the same CallerReference.

If CallerReference is a value you already sent in a previous invalidation batch request but the content of any Path is different from the original request, CloudFront returns an InvalidationBatchAlreadyExists error.

A complex type that contains information about the objects that you want to invalidate. For more information, see Specifying the Objects to Invalidate in the Amazon CloudFront Developer Guide.

A distribution configuration.

If you want CloudFront to respond to IPv6 DNS requests with an IPv6 address for your distribution, specify true. If you specify false, CloudFront responds to IPv6 DNS requests with the DNS response code NOERROR and with no IP addresses. This allows viewers to submit a second request, for an IPv4 address for your distribution.

In general, you should enable IPv6 if you have users on IPv6 networks who want to access your content. However, if you're using signed URLs or signed cookies to restrict access to your content, and if you're using a custom policy that includes the IpAddress parameter to restrict the IP addresses that can access your content, don't enable IPv6. If you want to restrict access to some content by IP address and not restrict access to other content (or restrict access but not by IP address), you can create two distributions. For more information, see Creating a Signed URL Using a Custom Policy in the Amazon CloudFront Developer Guide.

If you're using an Amazon Route 53 alias resource record set to route traffic to your CloudFront distribution, you need to create a second alias resource record set when both of the following are true:

• You enable IPv6 for the distribution

• You're using alternate domain names in the URLs for your objects

For more information, see Routing Traffic to an Amazon CloudFront Web Distribution by Using Your Domain Name in the Amazon Route 53 Developer Guide.

If you created a CNAME resource record set, either with Amazon Route 53 or with another DNS service, you don't need to make any changes. A CNAME record will route traffic to your distribution regardless of the IP address format of the viewer request.

(Optional) Specify the maximum HTTP version that you want viewers to use to communicate with CloudFront. The default value for new web distributions is http2. Viewers that don't support HTTP/2 automatically use an earlier HTTP version.

For viewers and CloudFront to use HTTP/2, viewers must support TLS 1.2 or later, and must support Server Name Identification (SNI).

In general, configuring CloudFront to communicate with viewers using HTTP/2 reduces latency. You can improve performance by optimizing for HTTP/2. For more information, do an Internet search for "http/2 optimization."

A unique identifier that specifies the AWS WAF web ACL, if any, to associate with this distribution.

AWS WAF is a web application firewall that lets you monitor the HTTP and HTTPS requests that are forwarded to CloudFront, and lets you control access to your content. Based on conditions that you specify, such as the IP addresses that requests originate from or the values of query strings, CloudFront responds to requests either with the requested content or with an HTTP 403 status code (Forbidden). You can also configure CloudFront to return a custom error page when a request is blocked. For more information about AWS WAF, see the AWS WAF Developer Guide.

From this field, you can enable or disable the selected distribution.

The price class that corresponds with the maximum price that you want to pay for CloudFront service. If you specify PriceClass_All, CloudFront responds to requests for your objects from all CloudFront edge locations.

If you specify a price class other than PriceClass_All, CloudFront serves your objects from the CloudFront edge location that has the lowest latency among the edge locations in your price class. Viewers who are in or near regions that are excluded from your specified price class may encounter slower performance.

For more information about price classes, see Choosing the Price Class for a CloudFront Distribution in the Amazon CloudFront Developer Guide. For information about CloudFront pricing, including how price classes (such as Price Class 100) map to CloudFront regions, see Amazon CloudFront Pricing. For price class information, scroll down to see the table at the bottom of the page.

A complex type that controls whether access logs are written for the distribution.

For more information about logging, see Access Logs in the Amazon CloudFront Developer Guide.

Any comments you want to include about the distribution.

If you don't want to specify a comment, include an empty Comment element.

To delete an existing comment, update the distribution configuration and include an empty Comment element.

To add or change a comment, update the distribution configuration and specify the new comment.

A complex type that controls the following:

• Whether CloudFront replaces HTTP status codes in the 4xx and 5xx range with custom error messages before returning the response to the viewer.

• How long CloudFront caches HTTP status codes in the 4xx and 5xx range.

For more information about custom error pages, see Customizing Error Responses in the Amazon CloudFront Developer Guide.

A complex type that contains zero or more CacheBehavior elements.

A complex type that describes the default cache behavior if you don't specify a CacheBehavior element or if files don't match any of the values of PathPattern in CacheBehavior elements. You must create exactly one default cache behavior.

A complex type that contains information about origin groups for this distribution.

A complex type that contains information about origins for this distribution.

The object that you want CloudFront to request from your origin (for example, index.html) when a viewer requests the root URL for your distribution (http://www.example.com) instead of an object in your distribution (http://www.example.com/product-description.html). Specifying a default root object avoids exposing the contents of your distribution.

Specify only the object name, for example, index.html. Don't add a / before the object name.

If you don't want to specify a default root object when you create a distribution, include an empty DefaultRootObject element.

To delete the default root object from an existing distribution, update the distribution configuration and include an empty DefaultRootObject element.

To replace the default root object, update the distribution configuration and specify the new object.

For more information about the default root object, see Creating a Default Root Object in the Amazon CloudFront Developer Guide.

A complex type that contains information about CNAMEs (alternate domain names), if any, for this distribution.

A unique value (for example, a date-time stamp) that ensures that the request can't be replayed.

If the value of CallerReference is new (regardless of the content of the DistributionConfig object), CloudFront creates a new distribution.

If CallerReference is a value that you already sent in a previous request to create a distribution, CloudFront returns a DistributionAlreadyExists error.

A complex type that lists the AWS accounts, if any, that you included in the TrustedSigners complex type for this distribution. These are the accounts that you want to allow to create signed URLs for private content.

The Signer complex type lists the AWS account number of the trusted signer or self if the signer is the AWS account that created the distribution. The Signer element also includes the IDs of any active CloudFront key pairs that are associated with the trusted signer's AWS account. If no KeyPairId element appears for a Signer, that signer can't create signed URLs.

For more information, see Serving Private Content through CloudFront in the Amazon CloudFront Developer Guide.

A complex type that contains one Signer complex type for each trusted signer that is specified in the TrustedSigners complex type.

For more information, see ActiveTrustedSigners.

A complex type that contains one Signer complex type for each trusted signer specified in the TrustedSigners complex type.

For more information, see ActiveTrustedSigners.

Enabled is true if any of the AWS accounts listed in the TrustedSigners complex type for this RTMP distribution have active CloudFront key pairs. If not, Enabled is false.

For more information, see ActiveTrustedSigners.

A complex type that identifies ways in which you want to restrict distribution of your content.

A complex type that specifies the following:

• Whether you want viewers to use HTTP or HTTPS to request your objects.

• If you want viewers to use HTTPS, whether you're using an alternate domain name such as example.com or the CloudFront domain name for your distribution, such as d111111abcdef8.cloudfront.net.

• If you're using an alternate domain name, whether AWS Certificate Manager (ACM) provided the certificate, or you purchased a certificate from a third-party certificate authority and imported it into ACM or uploaded it to the IAM certificate store.

You must specify only one of the following values:

• ViewerCertificate$ACMCertificateArn

• ViewerCertificate$IAMCertificateId

• ViewerCertificate$CloudFrontDefaultCertificate

Don't specify false for CloudFrontDefaultCertificate.

If you want viewers to use HTTP instead of HTTPS to request your objects: Specify the following value:

<CloudFrontDefaultCertificate>true<CloudFrontDefaultCertificate>

In addition, specify allow-all for ViewerProtocolPolicy for all of your cache behaviors.

If you want viewers to use HTTPS to request your objects: Choose the type of certificate that you want to use based on whether you're using an alternate domain name for your objects or the CloudFront domain name:

• If you're using an alternate domain name, such as example.com: Specify one of the following values, depending on whether ACM provided your certificate or you purchased your certificate from third-party certificate authority:

  • <ACMCertificateArn>ARN for ACM SSL/TLS certificate<ACMCertificateArn> where ARN for ACM SSL/TLS certificate is the ARN for the ACM SSL/TLS certificate that you want to use for this distribution.

  • <IAMCertificateId>IAM certificate ID<IAMCertificateId> where IAM certificate ID is the ID that IAM returned when you added the certificate to the IAM certificate store.

  If you specify ACMCertificateArn or IAMCertificateId, you must also specify a value for SSLSupportMethod.

  If you choose to use an ACM certificate or a certificate in the IAM certificate store, we recommend that you use only an alternate domain name in your object URLs (https://example.com/logo.jpg). If you use the domain name that is associated with your CloudFront distribution (such as https://d111111abcdef8.cloudfront.net/logo.jpg) and the viewer supports SNI, then CloudFront behaves normally. However, if the browser does not support SNI, the user's experience depends on the value that you choose for SSLSupportMethod:

  • vip: The viewer displays a warning because there is a mismatch between the CloudFront domain name and the domain name in your SSL/TLS certificate.

  • sni-only: CloudFront drops the connection with the browser without returning the object.

• If you're using the CloudFront domain name for your distribution, such as d111111abcdef8.cloudfront.net : Specify the following value:

  <CloudFrontDefaultCertificate>true<CloudFrontDefaultCertificate>

If you want viewers to use HTTPS, you must also specify one of the following values in your cache behaviors:

• <ViewerProtocolPolicy>https-only<ViewerProtocolPolicy>

• <ViewerProtocolPolicy>redirect-to-https<ViewerProtocolPolicy>

You can also optionally require that CloudFront use HTTPS to communicate with your origin by specifying one of the following values for the applicable origins:

• <OriginProtocolPolicy>https-only<OriginProtocolPolicy>

• <OriginProtocolPolicy>match-viewer<OriginProtocolPolicy>

For more information, see Using Alternate Domain Names and HTTPS in the Amazon CloudFront Developer Guide.

This field has been deprecated. Use one of the following fields instead:

• ViewerCertificate$ACMCertificateArn

• ViewerCertificate$IAMCertificateId

• ViewerCertificate$CloudFrontDefaultCertificate

This field has been deprecated. Use one of the following fields instead:

• ViewerCertificate$ACMCertificateArn

• ViewerCertificate$IAMCertificateId

• ViewerCertificate$CloudFrontDefaultCertificate

Specify the security policy that you want CloudFront to use for HTTPS connections. A security policy determines two settings:

• The minimum SSL/TLS protocol that CloudFront uses to communicate with viewers

• The cipher that CloudFront uses to encrypt the content that it returns to viewers

We recommend that you specify TLSv1.1_2016 unless your users are using browsers or devices that do not support TLSv1.1 or later.

When both of the following are true, you must specify TLSv1 or later for the security policy:

• You're using a custom certificate: you specified a value for ACMCertificateArn or for IAMCertificateId

• You're using SNI: you specified sni-only for SSLSupportMethod

If you specify true for CloudFrontDefaultCertificate, CloudFront automatically sets the security policy to TLSv1 regardless of the value that you specify for MinimumProtocolVersion.

For information about the relationship between the security policy that you choose and the protocols and ciphers that CloudFront uses to communicate with viewers, see Supported SSL/TLS Protocols and Ciphers for Communication Between Viewers and CloudFront in the Amazon CloudFront Developer Guide.

If you specify a value for ViewerCertificate$ACMCertificateArn or for ViewerCertificate$IAMCertificateId, you must also specify how you want CloudFront to serve HTTPS requests: using a method that works for all clients or one that works for most clients:

• vip: CloudFront uses dedicated IP addresses for your content and can respond to HTTPS requests from any viewer. However, you will incur additional monthly charges.

• sni-only: CloudFront can respond to HTTPS requests from viewers that support Server Name Indication (SNI). All modern browsers support SNI, but some browsers still in use don't support SNI. If some of your users' browsers don't support SNI, we recommend that you do one of the following:

  • Use the vip option (dedicated IP addresses) instead of sni-only.

  • Use the CloudFront SSL/TLS certificate instead of a custom certificate. This requires that you use the CloudFront domain name of your distribution in the URLs for your objects, for example, https://d111111abcdef8.cloudfront.net/logo.png.

  • If you can control which browser your users use, upgrade the browser to one that supports SNI.

  • Use HTTP instead of HTTPS.

Don't specify a value for SSLSupportMethod if you specified <CloudFrontDefaultCertificate>true<CloudFrontDefaultCertificate>.

For more information, see Using Alternate Domain Names and HTTPS in the Amazon CloudFront Developer Guide.

For information about how and when to use ACMCertificateArn, see ViewerCertificate.

For information about how and when to use IAMCertificateId, see ViewerCertificate.

For information about how and when to use CloudFrontDefaultCertificate, see ViewerCertificate.

A complex type that controls whether access logs are written for the distribution.

An optional string that you want CloudFront to prefix to the access log filenames for this distribution, for example, myprefix/. If you want to enable logging, but you don't want to specify a prefix, you still must include an empty Prefix element in the Logging element.

The Amazon S3 bucket to store the access logs in, for example, myawslogbucket.s3.amazonaws.com.

Specifies whether you want CloudFront to include cookies in access logs, specify true for IncludeCookies. If you choose to include cookies in logs, CloudFront logs all cookies regardless of how you configure the cache behaviors for this distribution. If you don't want to include cookies when you create a distribution or if you want to disable include cookies for an existing distribution, specify false for IncludeCookies.

Specifies whether you want CloudFront to save access logs to an Amazon S3 bucket. If you don't want to enable logging when you create a distribution or if you want to disable logging for an existing distribution, specify false for Enabled, and specify empty Bucket and Prefix elements. If you specify false for Enabled but you specify values for Bucket, prefix, and IncludeCookies, the values are automatically deleted.

A complex type that controls:

• Whether CloudFront replaces HTTP status codes in the 4xx and 5xx range with custom error messages before returning the response to the viewer.

• How long CloudFront caches HTTP status codes in the 4xx and 5xx range.

For more information about custom error pages, see Customizing Error Responses in the Amazon CloudFront Developer Guide.

A complex type that contains a CustomErrorResponse element for each HTTP status code for which you want to specify a custom error page and/or a caching duration.

The number of HTTP status codes for which you want to specify a custom error page and/or a caching duration. If Quantity is 0, you can omit Items.

A complex type that contains zero or more CacheBehavior elements.

Optional: A complex type that contains cache behaviors for this distribution. If Quantity is 0, you can omit Items.

The number of cache behaviors for this distribution.

A complex type that describes the default cache behavior if you don't specify a CacheBehavior element or if files don't match any of the values of PathPattern in CacheBehavior elements. You must create exactly one default cache behavior.

The value of ID for the field-level encryption configuration that you want CloudFront to use for encrypting specific fields of data for a cache behavior or for the default cache behavior in your distribution.

A complex type that contains zero or more Lambda function associations for a cache behavior.

Whether you want CloudFront to automatically compress certain files for this cache behavior. If so, specify true; if not, specify false. For more information, see Serving Compressed Files in the Amazon CloudFront Developer Guide.

The default amount of time that you want objects to stay in CloudFront caches before CloudFront forwards another request to your origin to determine whether the object has been updated. The value that you specify applies only when your origin does not add HTTP headers such as Cache-Control max-age, Cache-Control s-maxage, and Expires to objects. For more information, see Specifying How Long Objects and Errors Stay in a CloudFront Edge Cache (Expiration) in the Amazon CloudFront Developer Guide.

Indicates whether you want to distribute media files in the Microsoft Smooth Streaming format using the origin that is associated with this cache behavior. If so, specify true; if not, specify false. If you specify true for SmoothStreaming, you can still distribute other content using this cache behavior if the content matches the value of PathPattern.

The minimum amount of time that you want objects to stay in CloudFront caches before CloudFront forwards another request to your origin to determine whether the object has been updated. For more information, see Specifying How Long Objects and Errors Stay in a CloudFront Edge Cache (Expiration) in the Amazon Amazon CloudFront Developer Guide.

You must specify 0 for MinTTL if you configure CloudFront to forward all headers to your origin (under Headers, if you specify 1 for Quantity and * for Name).

The protocol that viewers can use to access the files in the origin specified by TargetOriginId when a request matches the path pattern in PathPattern. You can specify the following options:

• allow-all: Viewers can use HTTP or HTTPS.

• redirect-to-https: If a viewer submits an HTTP request, CloudFront returns an HTTP status code of 301 (Moved Permanently) to the viewer along with the HTTPS URL. The viewer then resubmits the request using the new URL.

• https-only: If a viewer sends an HTTP request, CloudFront returns an HTTP status code of 403 (Forbidden).

For more information about requiring the HTTPS protocol, see Using an HTTPS Connection to Access Your Objects in the Amazon CloudFront Developer Guide.

A complex type that specifies the AWS accounts, if any, that you want to allow to create signed URLs for private content.

If you want to require signed URLs in requests for objects in the target origin that match the PathPattern for this cache behavior, specify true for Enabled, and specify the applicable values for Quantity and Items. For more information, see Serving Private Content through CloudFront in the Amazon Amazon CloudFront Developer Guide.

If you don't want to require signed URLs in requests for objects that match PathPattern, specify false for Enabled and 0 for Quantity. Omit Items.

To add, change, or remove one or more trusted signers, change Enabled to true (if it's currently false), change Quantity as applicable, and specify all of the trusted signers that you want to include in the updated distribution.

A complex type that specifies how CloudFront handles query strings and cookies.

The value of ID for the origin that you want CloudFront to route requests to when a request matches the path pattern either for a cache behavior or for the default cache behavior in your distribution.

A complex data type for the origin groups specified for a distribution.

The items (origin groups) in a distribution.

The number of origin groups.

A complex type that contains information about origins and origin groups for this distribution.

A complex type that contains origins or origin groups for this distribution.

The number of origins or origin groups for this distribution.

A complex type that contains information about CNAMEs (alternate domain names), if any, for this distribution.

A complex type that contains the CNAME aliases, if any, that you want to associate with this distribution.

The number of CNAME aliases, if any, that you want to associate with this distribution.