Currently the main complaint people have about OCI tooling is the lack of a transition from Docker to OCI. With umoci you have a lot of low-level image configuration abilities, and skopeo and runC cover the other major parts of the picture, but you need something to tie them together.

I'm not going to be implementing YAWAR (Yet Another Wrapper Around Runc). It's just going to be a single script that can take a Dockerfile and create an OCI image that is basically the same as the Docker image you would get -- with the big difference being that you didn't need Docker and everything used the OCI. The other cool benefit of this is that you could build images without privileges (since rootless containers now exist in runC and in umoci).

https://github.com/cyphar/orca