The openstack user list command uses the Keystone service, which is the identity service for OpenStack. Keystone provides authentication, authorization, and service discovery for OpenStack. It also manages projects, users, roles, and endpoints for the OpenStack services

MPLSoUDP (Multiprotocol Label Switching over User Datagram Protocol) and VXLAN (Virtual Extensible LAN) are two protocols that provide tunneling in the overlay and support multipath capabilities45. MPLSoUDP is an encapsulation protocol that allows MPLS packets to be encapsulated in UDP packets. VXLAN is a network virtualization technology that attempts to address the scalability problems associated with large cloud computing deployments

 In a cloud-native microservices-based architecture, the various modules of an application communicate through application programming interface (API) calls5. Each service is autonomous and self-contained and runs a unique process6. References from Juniper site: Microsoft Learn, Palo Alto Networks