Change partition type from MBR to GPT for AWS AMI ?

[staff.rm]

Hello,
i noticed that the latest Ubuntu provided 18.04 AMI's for use with Amazon Webservices still use MBR/legacy-style partition tables and not the newer GPT ones?

Could that default be changes (at least looking for future releases (i.e. 19.10 ? )

That requires some extra (ugly) steps to i.e. in-place replace partition table when wanting to grow volume to >= 2TB.

According to AWS documentation Linux boot volumes can be both with mbr/gpt style tables:
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/volume_constraints.html

Especially the HVM instance types in Amazon have their boot sequence similar to a normal server system (mbr + bootloader) on the disk itself instead of relying on the old pv-grub (grub-legacy-ec2).

The latest Ubuntu bionic/18.04 AMI's seem to be hvm only anyway.
Note: That should mean that grub-legacy-ec2 should in theory not be needed anymore anyway but that's another topic...

Stefan

[Robert C Jennings (rcj)]

You are correct for EBS (that documentation links specifically to EBS boot volume considerations). I do not believe this is correct for AMIs with instance-store backed root disks. We had investigated this previously because we would like to support larger root volumes and we can check again, but we would not want to see the instance-store and ebs AMIs diverge. This would be a change for a future release as it would be inappropriate to change this for users of existing releases.

[Thomas Bechtold (toabctl)]

This is now done for Jammy (22.04) amd64 images. A daily image with this change should be available soon for testing. Closing this for now. Please reopen if you detect any problems.