What’s the Difference Between Continuous Delivery vs. Continuous Deployment?

Written by: Ethan Jones

Every DevOps user today is aware of CI/CD as a concept. CI stands for continuous integration, whereas CD is often used interchangeably to signify “continuous delivery” and “continuous deployment.”

Are they both the same thing? No.

Do they have a common goal? Yes.

While both practices look similar, there's a fine line between the two. Let’s explore what these two terms refer to in a DevOps environment.

Continuous delivery vs. continuous deployment

Continuous integration involves a series of steps that are automatically performed to integrate code from multiple sources, create a build and test. Each time a build or a set of code passes the tests, it’s automatically deployed out to a staging environment where further testing such as load testing and manual exploratory testing is conducted. This process can be repeated for days depending upon the project delivery requirements.

Continuous delivery helps you build a refined version of the software by continuously implementing fixes and feedback until finally, you decide to push it out to production. In other words, continuous delivery involves human decision-making around what to release to the customers, and when. This forms the basis of the difference between the two.

In continuous deployment, every change goes through an automated pipeline and a working version of the application is automatically pushed to production. It does not involve any release approval cycle and the project teams need to ensure that every time a code is updated, tested and released, it works smoothly at the customer’s end. Naturally, a lot depends on the quality of the test suite. With continuous deployment, teams can have multiple software deployments on any given day and don’t have to sweat about a major release.

Continuous delivery usually involves a production-like staging area with a mandatory time lag in the final release. This lag involves reviewing and manually accepting the changes in the code before releasing it to production.

In contrast, continuous deployment does not require a staging area for code changes to be manually reviewed and verified. This is because automated testing is integrated early in the development process and continues throughout all the phases of the release.

Consolidating delivery and deployment to attain a common goal

As a developer, you might feel that automating deployments might be risky or could have more advantages based on your confidence with CI/CD practices. Nonetheless, there are some legit constraints to applying continuous deployment in certain cases:

  • Regulatory compliances, marketing decisions, or other restrictions may prevent an IT organization from adopting continuous deployment.

  • Other considerations, such as the maturity of the DevOps process within an IT organization also influence the decision to automate the deployment of code.

As for continuous delivery, putting manual efforts in deploying code to production extends the delivery timeline. But there are legitimate reasons to why continuous delivery is a more convenient option for some enterprises.

Continuous delivery provides a competitive advantage for organizations that need their deployment decisions to be supported by authoritative human intelligence. It allows teams to deliver new features as they are ready, test working prototypes with real customers and build and evolve more stable, resilient systems.

This, in turn, reduces the ongoing costs of evolving products and services, improve their quality and reduce team burnout.

There are some exceptions where the concepts of delivery and deployment aren’t as relevant as they are elsewhere; for instance, if you’ve contributed to a library or created an artifact, you are unlikely to deploy it on a running system. In other words, there is no deployment phase. You simply push your code into a repository for other applications to consume. Similarly, with most web apps, teams often don't have separate build and deploy phases, which means there’s no apparent distinction between the delivery and deployment phase.

However, to automate deployments, you can explore high-end tools for application release orchestration. ARO comprehensively manages your software releases for:

  • Application packaging

  • Release versioning

  • Database updates

  • Server configuration management

  • Calendaring

  • Roll-forward and rollback

  • Security access

  • Auditing

Jenkins and Ansible are popular automation tools for CI/CD in the market. Various customizations of these tools and APIs are available that can embed add-on functionalities and enable productivity, respectively. Organizations can also follow blue/green deployment, canary deployment, feature flagging, etc. to automate both the delivery and deployment processes safely.

Continuous delivery, when rightly coupled with continuous deployment, strengthens the foundation of a DevOps pipeline and is core to agile DevOps initiatives. It fosters agile practices by giving testing and data center teams the tools required to automatically push the changes to production, get instant feedback and enable shorter release cycles.

These shorter release cycles enable you to deliver the highest possible software quality in a minimum TAT. And this becomes the sole purpose of implementing CI/CD in your software delivery pipeline. Are you able to accomplish that? If not, you need to reconsider, re-evaluate and evolve using a product like CloudBees CodeShip.

Get started with CloudBees CodeShip.

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