AWS DevOps Blog

CDK Corner – May 2021

Social – community engagement

According to Matt Coulter’s tweet, nearly 4000 people signed up for CDK Day to celebrate all things CDK on April 30. As a single-day, two-track event, there was a significant amount of content to learn from while having fun, and interacting with the CDK community.

Eric Johnson as the emcee, keynoted the first session of the morning, presenting “Better together: AWS CDK and AWS SAM.” This keynote was the announcement for the public preview of the AWS Serverless Application Model CLI (AWS SAM CLI). The AWS Serverless Application Model CLI includes support for local development and testing of AWS CDK projects.

To learn more, the blog post announcing the AWS SAM CLI public preview has more detail about the capabilities of the AWS SAM CLI.

If you missed CDK Day, fear not! CDK Day Track 1 and Track2 are available to watch online.

Great job and round of applause to the sign-language translators, the speakers, the organizers, and the hosts for making the second CDK Day a success! We can’t wait for CDK Day number 3!

Updates to the CDK

AWS CDK v2 developer preview

It’s here! The much-anticipated release of CDK v2’s developer preview is now available!

When using CDK previously, developers in JavaScript and TypeScript have faced challenges with the way that npm handles transitive dependencies; the dependencies that your dependencies rely on. For example, the aws-ec2 package.json file lists dependencies for other CDK construct libraries. If one of these transitive dependencies were updated, all of them would be need to be updated. Or you would run into dependency tree resolution errors, as seen in this StackOverflow thread.

With v2, all construct modules are now provided in a single package: aws-cdk-lib. All of the dependencies are now pinned to a single version of aws-cdk-lib, making it easier to manage. This also gives you the flexibility of having all CDK construct library modules available without having to run npm install each time you want to use a new construct library.

Another change to AWS CDK v2 is the removal of experimental modules. To help promote API stability and comply with semantic versioning, CDK v2 ships only with modules marked as stable.

Experimental modules aren’t going away completely, though. In v1, experimental modules and constructs will be provided together with no change. In v2, experimental modules are distributed and versioned separately from the aws-cdk-lib package, in their own dedicated package and namespace. Once a v2 construct is deemed stable, it is then merged into the aws-cdk-lib package.

The CDK team is still determining the best method of distributing experimental modules and constructs, so stay tuned for more information. Read more about the AWS CDK v2 developer preview in the What’s new blog post.

AWS CDK for Go developer preview

On April 7, the AWS CDK team announced support for golang. From the Go tracking issue on GitHub, nearly 900 members of the CDK community have requested for CDK to support golang, and we’re happy to see it become available! We are looking forward to helping out all the golang gophers out there build amazing CDK applications!

To learn more about Go and AWS CDK, read the AWS CDK for Go module API documentation on You can also read the Go bindings for JSII RFC document on GitHub. Want to contribute to the success of Go and CDK? The project tracking board for Go’s General Availability has tasks and items which could use your help.

Construct modules promoted to General Availability

Many new construct modules were promoted to General Availability recently. General Availability indicates a module’s stability, giving confidence to run these modules in production workloads. In April, a total of 15 modules were promoted stable:

Notable new L2 constructs

In the @aws-cdk/route-53 module, name server (NS) records were previously defined with the route53.RecordType enum. In PR#13895, user stijnbrouwers introduces the NS record as its own L2 construct: route53.NSRecord. bringing it into company with other record type L2s, such as route53.ARecord. This makes managing NS records consistent with the other record types represented as L2 constructs.

Improving the @aws-cdk/aws-events-targets module, CDK community user hedrall submitted PR#13823. This change brings support for Amazon API Gateway as a target for an Amazon EventBridge event.

@aws-cdk/aws-codepipeline-actions now includes an L2 construct for AWS CodeStar Connections supporting BitBucket and GitHub. This construct lets you create a CDK application that uses AWS CodeStar with a source connection from either provider, thanks to PR#13781 from the CDK Team.

Level ups to existing CDK constructs

Amazon Elastic Inference makes available low-cost GPU-acceleration for deep-learning workloads. PR#13950 now lets you use the service via @aws-cdk/aws-ecs in Amazon Elastic Container Service tasks, from CDK community user upparekh.

In PR#13473, from pgarbe, the @aws-cdk/aws-lambda-nodejs module will now bundle AWS Lambda functions with Docker images sourced from the Amazon Elastic Container Registry (Amazon ECR) Public Registry, instead of DockerHub. Prior to this change, CDK used your DockerHub credentials to pull a Docker image for the Lambda function. If your account was in DockerHub’s free-tier account level, your account is throttled whenever it exceeds the API limit within a short time frame set by DockerHub. This can cause your AWS CDK deployment to be delayed until you are under DockerHub’s API limit. By moving to the Amazon ECR Public Registry, this removes the risk of being affected by DockerHub’s API rate limiting . You can read more in this blog post giving customers advice about DockerHub rate limits from last year.

With @aws-cdk/aws-codebuild, you can use concurrent build support to speed up your build process. Sometimes you’ll want to limit the number of builds that run concurrently, whether for cost reduction or reducing the complexity of your build process. PR#14185, authored by gmokki, adds the ability to define a concurrent build limit for an AWS CodeBuild project Stage.

It is common for customers to have applications or resources spanning multiple AWS Regions. If you’re using @aws-cdk/aws-secretsmanager, you can now replicate secrets to multiple Regions, with PR#14266 from the CDK team. Make sure you’re not setting your secret as “test123” for your production databases in multiple Regions!

For users of @aws-cdk/aws-eks, PR#12659 from anguslees lets you pass arguments from to avoid the DescribeCluster API call. This will speed up the time it takes nodes to join an EKS cluster.

PR#14250 from the CDK team gives developers using @aws-cdk/aws-ec2 the ability to set fixed IPs when defining NAT gateways. This change will now pre-create Elastic IP address allocations and assign them to the NAT gateway. This can be useful when managing links from an Amazon Virtual Private Cloud (VPC) to an on-premises data center that relies on fixed/static IP addresses.

@aws-cdk/aws-iam now lets you add AWS Identity and Access Management (AWS IAM) users to new or existing groups. For example, you might want to have a user in a specific group for the life of a deployed CDK application. And on stack deletion, revoke that membership. Thanks to PR#13698 from jogold, this is now possible.

Learning – Finds from across the internet

If you work with CDK parameters, you might be curious how parameters derive their names and values. Borislav Hadzhiev released a blog post about setting and using CDK parameters.

Ibrahim Cesar’s wrote an awesome blog post detailing the experience of discovering and working with CDK. It’s an enjoyable read of inspiration and animated gifs.

Twitter user edwin4_ released a tool for CDK automation called RocketCDK. From the project’s GitHub repository, this tool will initialize your CDK app, install your packages, and auto-import them into your stack. Neat! Anything that helps save time is a plus-one.

Community acknowledgments

And finally, congratulations and rounds of applause for these folks who had their first Pull Request merged to the CDK repository!

*These users’ Pull Requests were merged in April.

Thank you for joining us on this update of the CDK corner. See you next time!