Instructions:
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/amazon-linux-2-virtual-machine.html
OS images can be found at:
https://cdn.amazonlinux.com/os-images/2.0.20220912.1/
Generate seed iso
genisoimage -output seed.iso -volid cidata -joliet -rock user-data meta-data
Further documentation on cloud-init: