TooManyDistributionCNAMEsException in AWS CloudFront
Introduction
Are you encountering the TooManyDistributionCNAMEsException error while working with AWS CloudFront? If so, you’ve come to the right place. In this article, we will dive deep into this exception, understand its causes, and provide solutions to address it effectively.
What is TooManyDistributionCNAMEsException?
The TooManyDistributionCNAMEsException is an error in Amazon CloudFront, which is the Content Delivery Network (CDN) provided by Amazon Web Services (AWS). When this exception occurs, it means that you have exceeded the maximum number of CNAMEs (Canonical Names) associated with a CloudFront distribution.
Understanding CNAMEs in CloudFront
Before we delve into the exception itself, let’s quickly understand what CNAMEs are in the context of CloudFront.
In CloudFront, a CNAME is an alternate domain name associated with a CloudFront distribution. Instead of using the default CloudFront domain (e.g., d1234.cloudfront.net), you can use your own custom domain (e.g., cdn.mydomain.com) by creating a CNAME record in your domain’s DNS configuration.
By using CNAMEs, you can serve your content through easily recognizable and branded domain names, enhancing your website’s branding and user experience.
Causes of TooManyDistributionCNAMEsException
CloudFront imposes a limit on the number of CNAMEs you can associate with a distribution. As of writing this article, the limit is set at 25 CNAMEs per distribution.
The TooManyDistributionCNAMEsException is triggered when you try to add additional CNAMEs to a distribution that has already reached this maximum limit. If you attempt to exceed this limit, cloudfront returns this exception.
Handling and resolving the exception
To resolve the TooManyDistributionCNAMEsException and add more CNAMEs to your distribution, you have the following options:
1. Review your CNAME configuration
The first step is to evaluate your existing CNAME configuration and ensure you genuinely need all the CNAMEs associated with the distribution. Consider removing any unnecessary CNAME entries.
Here’s an example of how to retrieve the CNAMEs associated with your CloudFront distribution using the AWS SDK for Java:
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import com.amazonaws.services.cloudfront.AmazonCloudFront;
import com.amazonaws.services.cloudfront.AmazonCloudFrontClientBuilder;
import com.amazonaws.services.cloudfront.model.*;
public class CloudFrontCNAMEsExample {
public static void main(String[] args) {
AmazonCloudFront cloudFrontClient = AmazonCloudFrontClientBuilder.defaultClient();
try {
GetDistributionConfigResult distributionConfigResult = cloudFrontClient.getDistributionConfig(
new GetDistributionConfigRequest("YOUR_DISTRIBUTION_ID")
);
DistributionConfig distributionConfig = distributionConfigResult.getDistributionConfig();
for (Aliases aliases : distributionConfig.getAliases().getItems()) {
System.out.println("CNAME: " + aliases);
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
This code snippet demonstrates how to retrieve and print the existing CNAMEs associated with a CloudFront distribution. Make sure to replace "YOUR_DISTRIBUTION_ID" with the actual distribution ID.
Review the list of CNAMEs obtained from your CloudFront distribution and determine if all of them are necessary. By eliminating any unnecessary CNAMEs, you can make room for the desired new CNAMEs.
2. Consider multiple CloudFront distributions
If the number of required CNAMEs exceeds the limit, you can distribute your content across multiple CloudFront distributions. By using multiple distributions, you can associate up to 25 CNAMEs with each distribution.
Here’s an example of how you can configure multiple distributions in your application code:
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import com.amazonaws.services.cloudfront.AmazonCloudFront;
import com.amazonaws.services.cloudfront.AmazonCloudFrontClientBuilder;
import com.amazonaws.services.cloudfront.model.*;
public class MultipleDistributionExample {
public static void main(String[] args) {
AmazonCloudFront cloudFrontClient = AmazonCloudFrontClientBuilder.defaultClient();
try {
CreateDistributionRequest request = new CreateDistributionRequest()
.withDistributionConfig(
new DistributionConfig()
.withComment("Sample Distribution")
.withAliases(new Aliases().withQuantity(1).withItems("cdn1.mydomain.com"))
);
CreateDistributionResult result = cloudFrontClient.createDistribution(request);
System.out.println("Distribution ID: " + result.getDistribution().getId());
} catch (Exception e) {
e.printStackTrace();
}
}
}
This code snippet demonstrates how to create a new CloudFront distribution using the AWS SDK for Java. In this example, we define a distribution and add a single CNAME to it. By creating multiple distributions, each with a different set of CNAMEs, you can overcome the CNAME limit.
3. Contact AWS Support
If neither of the above options suffices your requirements, you can reach out to AWS Support for assistance. AWS Support can help in scenarios where you need to increase the CNAME limit or if you have specific requirements that the standard limits do not accommodate. They can guide you through the process and find a suitable solution for your use case.
Conclusion
In this article, we explored the TooManyDistributionCNAMEsException error in AWS CloudFront, understanding its causes and offering possible solutions to resolve it. By reviewing your CNAME configuration, considering multiple CloudFront distributions, or seeking help from AWS Support, you can manage this exception effectively.
Remember, CNAMEs in CloudFront provide the flexibility to serve your content through branded domains, enhancing your website’s user experience. However, it’s essential to stay within the prescribed limits to ensure stable and reliable distribution.
Happy CloudFronting!