hyperkit

We'll probably use AHCI since hyperkit https://github.com/docker/hyperkit (the Mac hypervisor based on xhyve based on bhyve) lacks a virtio-scsi implementation at the moment. When the VM sends a TRIM ("these blocks aren't used any more, you can free them") we need to make use of this on the host. On Linux/BSD you could tell the host OS that the blocks aren't needed in the file using something like FALLOC_FL_PUNCH_HOLE and the kernel would take care of it e.g. by send TRIMs to the real storage device or shuffling filesystem metadata around. Unfortunately the Mac filesystems in common use don't support this so we'll need to manage this ourselves, e.g. by moving blocks from the end of the file into the middle and shrinking the file.

> Docker seems to be more portable to other host OSs, though? Most of the "Docker on Windows/Mac" setup is basically running all of the Docker containers in a VM on Windows or macOS (e.g. Docker Toolbox, boot2docker and not HyperKit[1]), rather than running them right in your OS's kernel as would be the case on Linux. [1] https://github.com/docker/HyperKit/

I think this is what you're looking for: https://github.com/docker/hyperkit Source: https://blog.docker.com/2016/05/docker-unikernels-open-sourc...

It's the latter. As we build up the Docker platform we're spinning out small individual components (the "plumbing") which other products can use and contribute back to. Here are a few of the components we have open-sourced recently: * https://github.com/docker/swarmkit * https://github.com/docker/hyperkit * https://github.com/docker/vpnkit * https://github.com/docker/datakit * https://github.com/docker/containerd * https://github.com/docker/notary * https://github.com/opencontainers/runc * https://github.com/docker/libnetwork * https://github.com/docker/libcompose

Open sourcing our libraries is obviously just the start. We're really keen to hear about any other uses that people might have and move HyperKit in the direction of easy integration with higher-level frameworks. For instance, direct ports of unikernel projects to run against the HyperKit kexec APIs would be really fun. Any takers for MirageOS or HalVM? :-) We've started keeping a list of "help wanted" issues for anyone interested in getting started with hacking in this area: https://github.com/docker/hyperkit/issues?q=is%3Aissue+is%3A...