openwhisk supports container factory implementations using docker directly, kubernetes, mesos, and soon YARN.
we should consider adding a firecracker implementation - https://github.com/firecracker-microvm/firecracker
It seems there is a project which aims to use firecraker as a containerd runtime.
https://github.com/firecracker-microvm/firecracker-containerd
@chetanmeh already has a prototype! https://github.com/apache/incubator-openwhisk/pull/4556