An existing configuration plugs itself onto an existing container installation that exists on your hard disk. This is by opposition to the Standalone Local Configuration which creates a new container installation from scratch in a directory of your choice. Existing configurations require that the user creates a valid configuration directory and points Cargo to it.
Whenever you configure or start a container which uses an existing configuration, Cargo will:
Please note that this method does not guarantee reproducibility, as the configuration is not "cleaned" at any point. If you want to keep a generated configuration you can ask Cargo to generate a standalone configuration once and then consider it an existing configuration.