c5d EC2 instances have internal NVMe storage. To use the advantage of NVMe internal disks in the terraform-aws-eks module as a Launch Template for the Autoscaler Groups the support was added in the following PRs:

• https://github.com/terraform-aws-modules/terraform-aws-eks/pull/1213
• https://github.com/terraform-aws-modules/terraform-aws-eks/pull/1404

In case you need a cost-effective AWS instance with high throughput and amount of IOPS this should be a good choice for EKS instances. A drawback could be instance has a fixed disk size of the NVMe disk.

More information about c5 instances with local NVMe storage can be found here:

• https://aws.amazon.com/blogs/aws/ec2-instance-update-c5-instances-with-local-nvme-storage-c5d/
• Comparsion between different disks and AWS instances: https://faun.pub/testing-the-waters-of-aws-ec2-c5d-instances-51fae49f33a3

List of supported AWS instances and other options in terraform-aws-eks module is defined by AWS CLI Reference in section option parameter ‘instance-type’ – https://docs.aws.amazon.com/cli/latest/reference/autoscaling/create-launch-configuration.html#options