The terms continuous delivery and deployment can sometimes be used interchangeably, but they’re not the same thing. Understanding continuous delivery vs deployment is critical to building high-performing digital products faster.
Here’s what you need to know about continuous delivery and deployment, the differences between them, and how to pick the right model.
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What Is Continuous Delivery?
Traditional software development methods deploy once every three to six months (often with delays). Continuous delivery takes an old concept — continuous integration — and applies it to deployment.
With continuous delivery, organizations can take several approaches. Typically, they release daily or weekly. Continuous delivery doesn’t always mean deploying daily — rather, it implies companies will be able to easily roll back faulty releases should problems arise. This way, no matter how large or small a release may be, users continue to experience consistently high quality and enhanced functionality over time.
In contrast to other approaches that simply address issues after they arise, continuous delivery tries to prevent problems from happening in the first place by using automated processes and test-driven development models.
When something does go wrong in production, there’s not much left to fix.
Many companies use continuous delivery in conjunction with continuous deployment, so their employees only have to commit code during normal business hours — as opposed to during core hours, when programmers are less likely to be available.
Automated testing tools enable developers and business users alike to submit changes into repositories, which then automatically process changes for regression tests, unit tests, and functional tests across all environments. This includes live operations for better efficiency, accuracy, and confidence in shipping. When something does go wrong in production, there’s not much left to fix.
Delivering software continuously has numerous benefits for IT departments and end users. Developers save time because they’re not waiting for code reviews or handoffs between teams. Continuous delivery lets developers automate workflows to expedite deployments even further.
Continuous delivery allows developers and IT teams more flexibility when rolling out products and features to end-users. This flexibility allows customers to receive critical improvements within days rather than months, enabling businesses that adopt these strategies to keep pace with evolving customer needs more quickly than those that don’t.
Overall, continuous delivery helps IT teams deliver high-quality software faster and with less risk. Finally, continuous delivery provides faster access to bug fixes because new versions are automatically tested before being deployed into production environments.
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What Is Continuous Deployment?
Continuous deployment is a software engineering approach in which teams push code to production multiple times per day. Proponents of continuous deployment say it allows them to build better software more quickly by delivering working code fast and often.
In a continuous deployment workflow, each check-in is verified by an automated build and/or test script, then automatically deployed into production. Each time new code is deployed, it is immediately available for use by users.
Each time new code is deployed, it is immediately available for use by users.
From a developer perspective, changes are committed to version control and then immediately moved into testing. Deployments often occur – usually more than once per day – but not so often that they become routine. With continuous deployment, developers can see how their changes will function in a live environment as soon as they make them.
This rapid feedback cycle means they can refine their solutions more quickly without introducing bugs, or risk impacting business operations. Users see only stable versions of software running between deployments, with no unintended behavior from earlier versions being run undercover.
Let’s take a look at some examples of continuous delivery vs continuous deployment.
Examples of Continuous Delivery and Deployment
A number of organizations have already adopted continuous delivery and deployment strategies. While each company has its own unique processes for getting code from developers to production environments, they all utilize some element of continuous delivery and in their process.
Etsy used Jenkins to set up a workflow that could automatically merge code into their main branch after successful unit tests were completed. Any developer can then deploy directly from that branch into production at any time.
Spotify also uses an automated build pipeline, with several deployments triggering off commits made to specific branches. Automated testing is then run on every commit before it’s deployed.
Companies like Facebook use continuous deployment extensively, because they make major changes several times a day, with small patches throughout each day. They do a rollback to ensure no regressions are introduced but rely on automated checks to do so.
Continuous deployment and continuous delivery allow developers to deploy code whenever it meets certain standards, instead of on a set schedule.
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Traditional Deployment vs Continuous Deployment
One of the main differences between traditional deployment and continuous deployment is how you go about creating a deployable artifact. With traditional deployments, your code gets deployed to production at set intervals, such as once per week or once per month.
Continuous deployment isn’t appropriate for everyone or every situation.
Continuous deployment pushes code into production as soon as it’s ready, whereas traditional deployment requires an entire interval to lapse before deploying new code into production.
That said, continuous deployment isn’t appropriate for everyone or every situation. It requires close monitoring from engineers, who need to be on call regularly in case something goes wrong. If any problems occur, those engineers must put out fires quickly and seamlessly restore service to customers.
Why Opt for a Continuous Model?
It comes down to speed and predictability. With traditional deployment, you typically get a large batch of changes deployed all at once. That can lead to big issues if there’s a critical failure in any of those changes. Your whole system is broken until you can isolate and fix that one component. With the continuous model, you push smaller batches of change out more frequently, so there are always working pieces for your users.
Traditional deployments are not meant for agile development methods. Traditional deployments only allow you to fix one problem at a time. However, with continuous deployment, several issues can be fixed simultaneously, resulting in a better overall product over time.
The goal with continuous delivery and continuous deployment processes is rapid feedback. Continuous delivery aims to get changes into production rapidly while maintaining stability through practices like automated testing and built-in monitoring. Continuous deployment happens every time there are changes made to your code that are approved by QA.
The difference between continuous delivery vs deployment — and why developers might want to consider one or both techniques — is primarily found in how quickly your team gets new features into users’ hands.
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