Got an email from Google saying they are “improving the experience of the Free Tier” by discontinuing F1-micro type of instance in favor of E2-micro type and I need to switch if I want to continue receiving the Free Tier discount.
E2-micro instances get 12.5% of 2 vCPUs, are allowed to burst up to 2 full vCPUs for short periods and have 1 Gb of RAM.
After rebooting my VM into E2-micro type I decided to upgrade Ubuntu as well.
Evidently something has changed in the initramfs-tools package since the last time I did maintenance because instead of trying to adjust LZMA2 dictionary size while compressing an initramfs image using xz archive tool it just quit with an error. Initramfs image is built every time you install a new version of a kernel image so this prevented the upgrade from finishing properly.