Continuous deployment
Continuous deployment is a software engineering approach in which software functionalities are delivered frequently through automated deployments. CD contrasts with continuous delivery, a similar approach in which software functionalities are also frequently delivered and deemed to be potentially capable of being deployed but are actually not deployed.
In an environment in which data-centric microservices provide the functionality, and where the microservices can be multiply instantiated, CD consists of instantiating the new version of a microservice and retiring the old version as it has drained all the requests in flight.