This presentation describes XOS, a service composition layer used by CORD and SEBA. XOS works at the abstract service level, focusing on how to integrate, configure, compose, and manage the lifecycle of services. XOS supports a variety of opensource technologies, such as Kubernetes, OpenStack, VOLTHA, and ONOS. XOS can leverage existing Infrastructure-as-a-Service to deploy the compute resources of a service, or XOS can integrate already-deployed services. XOS is more than just a registry of services, it is also a mechanism for describing the interactions between services, and for developing workflows that span services. XOS services are inherently multi-tenant, making it possible to both build service meshes that span multiple security domains, and to construct fine-grain service chains that traverse the entire mesh. Three technologies make up XOS: (1) a data model provides abstractions for services and tenants, (2) a generative toolchain allows extension of the data model, and (3) a goal-directed synchronization framework applies the data model to the services. This presentation covers each of these three aspects of XOS, provides examples motivated by common SEBA services, and shows how XOS is now being used in a multi-cloud environment that spans edge and commodity clouds.
