Pronounce the name like the Ancient Roman border wall, not like the fruit.

OpenStack groups access into three levels:
* the cluster (the sum of all the resources in an OpenStack installation, e. g. hypervisors or storage capacity)
* Keystone domains within that cluster
* Keystone projects within each domain

Limes enables a similar hierarchy for resource usage and quotas: After having reviewed the cluster's capacity, a cluster admin can allocate quotas to domains. The domain admin can then sublease that quota to its projects. Limes will then write these approved project quotas into the backend services that actually manage the resources. Limes also tracks resource usage in all projects in all domains, so that users can make informed decisions about resource allocation at all levels of the hierarchy.