Continuous deployment

Continuous deployment (CD) is a software engineering approach in which software functionalities are delivered frequently and through automated deployments.^[1][2][3]

Continuous deployment contrasts with continuous delivery (also abbreviated CD), 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.^[4] As such, continuous deployment can be viewed as a more complete form of automation than continuous delivery.^[5]

Motivation

A major motivation for continuous deployment is that deploying software into the field more often makes it easier to find, catch, and fix bugs. A bug is easier to fix when it comes from code deployed five minutes ago instead of five days ago.^[6]

Example

In an environment in which data-centric microservices provide the functionality, and where the microservices can have multiple instances, continuous deployment consists of instantiating the new version of a microservice and retiring the old version once it has drained all the requests in flight.^[7][8][9]

See also

• CI/CD, the combined practices of either (more often) continuous integration and continuous delivery, or (less often) continuous integration and continuous deployment
• Canary release
• Blue–green deployment