krunvm VS lima

Lots of cool hybrid container/VM ideas are being developed!

Bootable Container Images are a standard for launching VMs from OCI images: https://containers.github.io/bootable/

crun-vm (https://github.com/containers/crun-vm) is similar to RunCVM in that it can launch container images (or VM disk images) in VMs. It's an OCI runtime so it fits into the podman, Docker, or Kubernetes model.

krunvm (https://github.com/containers/krunvm) is a standalone tool with a similar workflow where you can launch a VM from an OCI image. It predates Bootable Container Images, so I think it injects its own kernel.

This project creates self-hosted (ephemeral) GitHub runners based on krunvm [1]. krunvm creates microVMs, so the project enables fully isolated runners inside your infrastruture. MicroVMs boot fast, providing an experience close to running containers. The project starts VMs based on the multi-platform OCI images that it creates -- ubuntu [2](default) or fedora [3]. The default is to create far-less capable runners than the GitHub runners, but most settings are similar to when running at GitHub: same user ID, member of the `docker` group, password-less `sudo`, etc. Since krunvm runs on MacOS, this should also run on MacOS -- although I haven't been able to test it: reports and/or PRs are welcome.

[1]: https://github.com/containers/krunvm

An interesting alternative is krunvm. On my MacBook Pro M1 it takes less than a second to start a VM and get a Linux shell prompt with krunvm . When I boot up a Fedora CoreOS on the same computer it takes about 17 seconds. Note though that krunvm is for managing lightweight VMs created from OCI images.

Lima provides a lightweight alternative to Docker Desktop for macOS users, offering better resource efficiency and native Apple Silicon support.

Docker is a company that maintains the Docker software and also offers a cloud service to run Docker containers in the cloud. They run DockerHub, which is a platform to store share and run Docker images. The actual standard for Docker containers is called OCI (Open Container Initiative). Because Docker is based on OCI there are many other tools that can interact with Docker containers, like Podman or Lima. If you want to go really deep, I really recommend reading the OCI specification! It's long but super interesting.

I'm currently using colima, and none of the other alternatives that I have found support forwarding UDP ports, which I use a lot, so that's a bummer!

Thankfully, lima has landed a new port forwarder with UDP support! [0]. I'm hoping to be able to use it soon once it makes into a release.

[0]: https://github.com/lima-vm/lima/commit/13e9cbcabc6a0a05ec389...

Lima can launch Ubuntu VMs easily: https://github.com/lima-vm/lima/blob/master/examples/ubuntu....

You can run a virtual machine (e.g. lima) from inside a nix-shell, exactly as you would do with a regular shell.

for others similarly curious, here's an example of the thing: https://github.com/noop-inc/template-java-spring-boot/blob/m...

they seem to be using the excellent lima <https://github.com/lima-vm/lima#readme> for booting on macOS; I run colima for its containerd and k8s support but strongly recommend both projects $(brew install lima colima)