Community Koha plus additional patches needed for ByWater Partners
Koha is a free, open-source, web-based library management system (ILS) that helps libraries streamline operations and improve user services. It's used by libraries of all sizes worldwide and is built using library standards and protocols. Koha is a fully featured, scalable library management system with a configurable user interface, adaptable for any library type, and has been translated into many languages.
Free & Open Community Edition Server in a Complete Virtual Machine
...Also, read the koha guidelines, given on the Wiki Page of this site, for choosing the right hardware resources.
Backup the system regularly, to avoid any issues, as in the video.
Google Search helps in finding more about Koha.