containerd.io is required for docker howerver it is not avilable in official yum repos. It needs to be installed directly from docker. ref: https://docs.docker.com/install/linux/docker-ce/centos/ https://linuxconfig.org/how-to-install-docker-in-rhel-8
Vagrant Core Plugins
These are plugins that ship with Vagrant. Vagrant core uses its own plugin system to power a lot of the core pieces that ship with Vagrant. Each plugin will have its own README which explains its specific role.