Comparing Continuous Delivery vs Deployment: Which Should You Choose?

Continuous Delivery and Continuous Deployment are often used as interchangeable terms, however, they differ greatly. But you can’t assess which one you should choose without first understanding the CI/CD pipeline. 

CI/CD is a framework used by DevOps teams to deliver the highest quality software, as speedily as possible. The CI/CD pipeline includes two phases, the first being Continuous Integration (CI). In this phase, developers build, test, and merge code changes into the main software branch. 

In the second phase, CD most frequently references Continuous Delivery, which is when developers focus on enabling code to be released for production. Continuous Delivery builds upon Continuous Integration by deploying all code changes to a testing environment and/or a production environment after the build stage.

Then, there’s Continuous Deployment, which can also be the CD in the CI/CD pipeline. Continuous Deployment is the frequent and automated deployment of the repository to a production environment after automated testing, to ensure code is always in a deployable state. Continuous Deployment can be considered an expansion of Continuous Deployment.

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Related Article: How to Implement Continuous Integration

What are the Differences Between Continuous Delivery vs. Continuous Deployment?

At first glance, Continuous Delivery and Continuous Deployment seem quite similar. Both Continuous Delivery and Continuous Deployment aim to automate the process of moving builds out of a code repository and into the next stage as quickly as possible, to prevent bottlenecks. 

While the goals may seem similar, there are key differences between Continuous Delivery and Continuous Deployment. 

Continuous Delivery can be best described as automating the functions of the software delivery pipeline. That includes testing the build for flaws or bugs and uploading the build to a repository. 

Continuous Delivery is also a practice where code changes are automatically prepared for a release to production and/or a production environment after the build stage. When properly implemented, developers will have a deployment-ready build, passed through a standardized testing process. Continuous Delivery keeps code in a deployable state, but the final push of code is made by a human, not automation.

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Continuous Deployment is the automation of the steps needed for deploying a build for safer releases. It’s best to think of Continuous Deployment builds on the work of Continuous Delivery. With Continuous Deployment, every change that passes through the production pipeline is then released to users. Continuous Deployment operates without human labor, and only a failed test will prevent a new change to be deployed to production.

To simplify: Continuous Delivery is the automated delivery of code to production environments, while Continuous Deployment automates the deployment to production. 

Related Article: What’s the Difference Between Continuous Delivery and Continuous Deployment?

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When to Use Continuous Delivery?

Continuous Delivery is best used to automate the steps to safely push code changes into production. Your DevOps teams should use Continuous Delivery when the goal is to always keep the code in a deployable state. To achieve this, code does not need to be perfect or complete, but it does need to be vetted and tested. 

Continuous Delivery ensures that all of the testing steps, incremental deployments, environmental deployments, and validation steps are safely delivering changes into the test environment. 

Continuous Delivery also aims to rapidly move builds out of a central code repository and into the test environment. Thus, Continuous Delivery requires an automation engine to move the build, in addition to automated testing for the builds once in the test environment. 

A few more quick guidelines for when to use Continuous Delivery:

• If you’re testing cycles are less mature, start with Continuous Delivery over Continuous Deployment

• If you don’t have documentation in place for your teams to use, then it’s better to start with Continuous Delivery over Continuous Deployment.

• Start with Continuous Delivery to improve communication between departments

Bottom line? Continuous Delivery creates an efficacious and repeatable software release process, which spells faster and more reliable building, testing, and releasing of software.

When to Use Continuous Deployment?

Continuous Deployment is best used as a second pathway to production, where the final steps are automated so that changes and/or problems are corrected and installed as quickly as possible.

It’s also helpful to think of Continuous Deployment as pushing Continuous Delivery one step further, by automating deployment into production after builds have been tested. With Continuous Deployment, there is no need for manual deployment to production, which lessens the workload on DevOps teams.

Additionally, it’s best to employ Continuous Deployment if you’re ready to speed up the entire SDLC. Once the development team has written code changes, Continuous Deployment ensures changes zip through the pipeline and straight into production.

Continuous Deployment supports DevOps teams looking to create more transparency and consistency in their software development processes, as everything is automated. Continuous Deployment can help your team better process documentation since automation engines run all aspects of each stage post-code writing.

If your testing cycles are mature and reliable, then your team is also in a good position to consider employing Continuous Deployment. Since it relies on automated testing to catch errors, it’s most dependable within a tried and true testing cycle.

Lastly, it might be best to use Continuous Deployment when you plan to use a user as the tester and speed up releases since every code change is automatically deployed to production.