I do, AWS Graviton2 (t4g) and Graviton3 (m7g) and some Ampere Altra (no, not the full machine with 80 cores, only small VMs part of the huge machine) 
Lot of other hosting companies are starting to show offerings using Ampere Altra, so things looks promising in that front! 
Since I still use Intel/AMD for development, I use my own container based on musl (Alpine Linux) to build static versions of the applications to deliver them.
For that, I combine Crystal + zig cc and the static version of the libraries needed for aarch64 and use crystal build --cross-compile.
There are a few caveats:
- If your app depends on OpenSSL, you need to be careful as it will try to use pkg-config and point to your local version of OpenSSL instead of the target one (trick is to set
PKG_CONFIG_LIBDIRand point to the cross-compilationpkgconfigdirectory for aarch64. - Even that compiles successufly, there might be issues with OpenSSL across distros, as it will not be able to find
/etc/ssl/certsin some or find other issues. so far (
) static musl runs without issues on Ubuntu 22.04 LTS - Multi-threading is a bit flaky at this stage (
-Dpreview_mt), I don’t have concrete examples, but encountered random errors that are hard to reproduce.
I showed a little bit of this in a few videos here and here.
I’ve also prepacked a list of dependencies in magic-haversack repository, so you only need to download, extract and then combine with your local Crystal and zig compiler to produce those static binaries targeting aarch64-linux-musl.
I was hoping to do part 3 showing automated cross-compilation using GitHub Actions but got a bit trickier to generate MacOS binaries (due MacOSX SDK version mismatch). More to come on that at some point 
Enjoy!