Comment 2 for bug 1803173

Hello,

I know that /sys/devices/virtual/dmi/id/product_uuid gives the unicity of the instance to cloud-init on Azure platform.
In this case, after upstream kernel install, that UUID value gets from upper case to lower case.

Example:
before kernel install: B016A6CF-B90D-B743-8379-902BBF5E0037
after upstream kernel install: b016a6cf-b90d-b743-8379-902bbf5e0037

I checked the linux kernel tree and I found the commit responsible for this change:
https://github.com/torvalds/linux/commit/712ff25450bd01366301eef81c33e865d901e7b7#diff-f2bd14bc67b5e2da67116bca971bbd0b

It seems that the current 16.04/18.04 Azure kernels do not have this patch and when I install the upstream kernel, the UUID changes -> cloud-init reprovisions the instance.

This issue is similar to https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1551419.

Thank you,
Adrian Vladu