I'd love to be able to configure the base image/VM in a way that doesn't bundle coding tools or anything else I don't need, and comes with some other binaries installed (I'm more interested in using this as an API for a sandbox use-case I have). Is there a way to do this at the moment / is this on the roadmap?
Another option would be configuring the sprite via checkpoint and then cloning the checkpoint from a base sprite, but I don't see this option anywhere either.
If the fat bundled environment harmful for you, or just extra stuff you don't care about?
In the longer term, docker is nice from a reproducibility + CI perspective, and a docker build is already something can easily work with and track in my system.
One thing I've heard but not verified with other sandboxed execution providers is that startup times for custom images can be quite slow, so it could be a potential differentiator given Fly's existing infra.