EC2 user data in CDK

This is a simple example from the @aws-cdk/aws-ec2 core library.

this.instance.addUserData('yum install -y https://s3.amazonaws.com/ec2-downloads-windows/SSMAgent/latest/linux_amd64/amazon-ssm-agent.rpm');

https://github.com/aws/aws-cdk/blob/48c26c2f59cb8c30a592af98a367f59d0995f5f3/packages/%40aws-cdk/aws-ec2/lib/bastion-host.ts#L136

It uses the addUserData method on the ec2.Instance class. You just pass it a list of commands and it adds the commands to the user data script. https://docs.aws.amazon.com/cdk/api/latest/docs/@aws-cdk_aws-ec2.Instance.html#add-wbr-user-wbr-datacommands

A more complicated example can be seen in the @aws-cdk/aws-eks core library. There is a renderUserData function that creates a list of commands to add to the user data.

• function: https://github.com/aws/aws-cdk/blob/22fe0ce5d5c39564c85f2a4af6f150bd8fac1bae/packages/%40aws-cdk/aws-eks/lib/user-data.ts#L6

• function used: https://github.com/aws/aws-cdk/blob/22fe0ce5d5c39564c85f2a4af6f150bd8fac1bae/packages/%40aws-cdk/aws-eks/lib/cluster.ts#L511

• test showing it rendered in CloudFormation: https://github.com/aws/aws-cdk/blob/22fe0ce5d5c39564c85f2a4af6f150bd8fac1bae/packages/%40aws-cdk/aws-eks/test/integ.eks-cluster.defaults.expected.json#L1069