We're working towards getting full ENA support enabled as part of the process of switching the Ubuntu AMI's to a custom Ubuntu kernel for AWS, some time in the near future. In the meantime, you are welcome to use our in-test development AMI's which already include that custom kernel and do have enaSupport enabled. You can find those AMI's by searching the AWS Community AMI's for "ubuntu/images-testing-dev/hvm 201703" (or a more recent YYYYMM).
@Mathias-
We're working towards getting full ENA support enabled as part of the process of switching the Ubuntu AMI's to a custom Ubuntu kernel for AWS, some time in the near future. In the meantime, you are welcome to use our in-test development AMI's which already include that custom kernel and do have enaSupport enabled. You can find those AMI's by searching the AWS Community AMI's for "ubuntu/ images- testing- dev/hvm 201703" (or a more recent YYYYMM).