Instead of having to update these flavor.rb files every time a new version of CentOS/RHEL come out let's dynamically pick up the version (7,8,9) from the machine. This was inspired slightly by the Rocky Linux guest flavor.rb.
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.
Generate proto
grpc_tools_ruby_protoc -I . --ruby_out=gen/plugin --grpc_out=gen/plugin ./plugin_server.proto