A service describes the collection of all settings and necessary resources (like managing users, setting permissions, starting containerized applications, etc.) as a single point of configuration and execution.
Hence, a service - once enabled - may automatically add several users, establish connections, start containerized applications which perform some kind of data manipulation tasks for example. When disabled, all users, connections, and containerized applications created before will be removed again.
In more technical words, a service describes a set of resources, their parametrization and relations in between. Services closely follow the Infrastructure as Code idea and are modelled very similar to Amazon’s CloudFormation project (https://aws.amazon.com/de/cloudformation).
Services are installed using a commissioning file. Within this text-base file in YAML format all resources including their parametrization must be listed.