RabbitMQ is an AMQP messaging system that is responsible for internal communication between the components of one OpenStack service, for example between nova-compute and nova-api.


A region is a physical separation of OpenStack resources bound by latency. (Region in this context is defined at a higher level than Nova’s definition of region.


Remote direct memory access (RDMA) is a technology that enables computers to read and write data from remote server without involving the CPU. RDMA helps to reduce latency and increase throughput by freeing up the CPU to perform other tasks.


Remote desktop protocol (RDP) is a computer protocol that provides a user with access to a remote system over the network.


Reclass, or Recursive External Classifier, is a software component that SaltStack uses to provide information about the nodes in your MCP cluster including variables and applications the nodes must run.