runC is a CLI tool for spawning and running containers according to the
OCI specification.  Containers are started as a child process of runC
and can be embedded into various other systems without having to run a
daemon.  runC is built on libcontainer, the same container technology
powering millions of Docker Engine installations.  runC does not force
you to have a particular workflow or deployment setup, it only requires
a root filesystem and configuration.

Docker images can be run with runC.