Dropping ARM64 support from Container Linux

[Benjamin Gilbert]

Hi all,

In the upcoming weeks, we plan to remove support for the ARM64 architecture
from Container Linux. Beginning with alpha 1855.0.0 on July 31, we will no
longer ship ARM64 images for new releases. At a later date, we will
additionally remove all ARM64 support from our source repos, including
Portage profiles, kernel configs, and tooling. Existing ARM64 machines
will continue to function, but will not update to future versions of
Container Linux.

We're taking this step in order to streamline the development and
maintenance of Container Linux throughout its remaining lifespan. Support
for the ARM64 architecture requires ongoing maintenance work, and our
metrics as well as informal reports indicate that there is no meaningful
use of Container Linux on ARM64. If you are making substantive use of
Container Linux on ARM64, please let us know; we’d consider delaying the
removal if necessary to reduce disruption to an existing user base.

We'd like to thank the Container Linux community, and most especially Geoff
Levand, for their work over the years to improve the state of Container
Linux on ARM64 and to extend its reach.

--Benjamin Gilbert