Continuous Deployment (CD) is an autonomous release process that uses automated testing to validate changes for instant auto deployment to a production environment.

As good software practice, developer often break big task into small piece for smooth development and integration in other side it’s also good for end user to grasp the small changes.

But releasing software frequently is not easy task. Frequent release come with cost and load on developer too.

In continues deployment code changes are continuously released into the production environment. Whenever developers change or update codes, Continuous deployment allows a new version to release automatically to end-users. In this practice, codes are run and maintained in a simulated environment to ensure the ultimate quality.

Benefits of Continuous Deployment:

• Frequent Release – Continues deployment enable frequent release, As soon as code is developed, it will get deployed on production environment. Instead of trying to release sets of changes every couple of weeks, Developer will be able to release multiple times per day. It helps to break feature down into smallest pieces and as soon as the we are done with development it on production environment.
• Focus on Development – Continues deployment enable developer to focus on development, as soon as code is developed, users are using it. If there is any bug, developer needs to focus on last changes which he/she made. Continues deployment also enable automated testing before the build to validate the change made by developer on code base. It helps developer to focus on the development.
• Flexibility –Continues deployment developers work on smaller piece, it give clear picture to developer about the feature they are working upon and easily can take over the other task.

Continues Deployment also has some problems and issues, especially if you are moving from the traditional delivery of every few months to continuous delivery.

• It requires new skill sets that a traditional software development house will not have.
• It requires a big investment in extra tools and hardware. Traditional software development will have a live system, a test system, and a production support system.
• If your architecture includes legacy systems, they may not be able to support continuous delivery without significant rework.
• If you are developing a business system, there may be a significant cost involved with keeping the users trained and up to date. If you have to use a system for your job, consistency may trump a great user experience. It’s amazing what people can get used to if they are paid to do it.

Developer often get confused with Continuous Integration, Continuous Delivery and Continuous Deployment.

Continuous Integration

Continuous Integration means continuously building and testing the application for every commit so that if application build or test failed, the developer is informed about it immediately.

Continuous Delivery

Continuous Delivery is a software engineering practice that code changes are prepared to be released to production. It is noticeable that these code changes must pass the automated unit testing, integration testing, system testing already. Continuous delivery enables developers to release whenever they want due to the releases available in the staging environment. In other words, the release involves human decisions.

Conclusion

Continuous deployment importance is vary based on the project to project e.g. When you hit a ceiling where the new deployment doesn’t add any value, or even a point when each new increment of deployment adds less and less value while adding more and more cost; continuous deployment would be less and less worth it (Cost vs Return).

Continuous Integration, Continuous Delivery, and Continuous Deployment are different process used for Rapid development, delivery and deployment.