Updates to AWS EC2 AMI defaults

[prestist]

Describe the enhancement

With the upcoming development on F39, we should make a few changes in bulk as there is a overhead overlap between the following changes.

• Update our AWS AMIs with the IMDSv2-only flag
  • Since IMDSv1 is not part of this consideration, there is some potential application breakage. We need to be sure to announce this change in the f39 rebase and opening of next
• Default EC2 AMI's to the gp3 EBS volume type
  • The gp3 volume type has a lower minimum IOP rating for volumes smaller than 3TB. We should include it in the release notes to inform the enduser of the default change.
• Switch AMIs to uefi-preferred
  • Existing Draft PR

System details

F39

Additional information

These were discussed in the FCOS community meeting 5/31/23

xref:

• tracker: Fedora 39 changes considerations #1491

[bgilbert]

Since the gp3 volume type has a higher minimum IOP rating (3000) we should include it in the release notes

The concern is that it has a lower minimum IOPS for volumes > 3 TB, and a minimum throughput that ranges from "slightly lower" to "half as much" depending on the volume size.

[quentin9696]

@bgilbert At my job, we already use gp3 with default IOPS option on FCOS in production and we don't have any complains about using gp3

[bgilbert]

@quentin9696 My point wasn't that we shouldn't switch, just that we need to announce that we're doing so.

[quentin9696]

@bgilbert this can also reassure people who are using it with the current disk

[dustymabe]

Some docs for the IMDSV2 changes:

• AWS Overview
• Example accessing via curl
• Example change in one of our FCOS tests