As discussed in last week's team meeting, I have been testing cloud-init 20.2-2~bpo10+1 with the goal of gathering confidence to request that the stable release term permit us to update that package buster. My focus has been on Amazon EC2, as Azure and OpenStack are being tested by others.
I've used a variation on the automation published at https://salsa.debian.org/trstringer/azure-debian/-/blob/master/buster/sru_validate_debian_debian-10_10_0.20200511.260_with_cloud-init_20.2-2_bp.sh for some of the testing. I'll publish the script and some test results tomorrow, as I'm about out of time for tonight, but the short story is that the tests have not uncovered any issues or surprises. I have also tested the update with some personal projects that make use of things like MIME multipart userdata, and have not encountered any regressions. I've tested using both IMDSv1 and v2. So far, so good... noah