Continuous deployment is a strategy in software development where new code updates or changes are delivered directly to live production environments.
In the continuous deployment process, as developers make changes to the software code, the changes are continuously put through rigorous testing processes which remain in effect throughout every stage of development. What makes continuous deployment unique is that changes are carried through the process automatically; there is no need for human intervention during this stage—the rigorous testing process is automated, which allows for a faster, more efficient turnaround. The changes themselves are continuous, and only a failed test or stage will stop the code from going live.
Once it passes through development, the update is automatically put into use where customers and clients will benefit from the changes immediately.
The goal of continuous deployment is to minimize the amount of time in the development cycle and allow essential changes to take effect more quickly. With continuous deployment, code can go directly from development, to testing, to deployment, to feedback without losing valuable time between each step. Continuous deployment can help improve the efficiency of code updates and ensure that customers have the newest version of the application in their hands right when they need it.
Continuous deployment is often confused with other similar—and similarly named—processes, such as continuous delivery. Continuous deployment and continuous delivery are two different approaches to releasing software changes, even though the two terms follow a similar process.
Continuous delivery is a software development process, like continuous deployment. In continuous delivery, developers make updates or other changes to the code and put it through automated, rigorous testing to ensure that the changes will be compatible with the application and will not cause any other problems. Where delivery differs from deployment is that once an update passes testing, it doesn’t necessarily go to production. For example, it may wait for a human developer to approve it, or it may be reliant on other changes that must be implemented before it is pushed live. But once the delivery is approved, the delivery process is automated, and the code changes are implemented for the users.
To reiterate, continuous deployment and continuous delivery are both software development practices that aim to streamline the release process and deliver software changes more efficiently. The key difference is that continuous delivery is focused on getting code ready for deployment but must wait on some sort of approval or other relevant triggers before it can be pushed live. Continuous deployment, on the other hand, automates deployment; once a change passes through testing it is automatically deployed.
But continuous deployment doesn’t mean that bad code is being released. Even without human approval, continuous deployment demands that development teams follow correct DevOps practices to ensure that every change they make is in line with development standards. Whether it is deployed when ready may depend on many factors, such as change controls, collation of features into a release, waiting for staged rollout results, and other similar checks.
Continuous deployment involves managing all these options and finding a way to continue the deployment automatically. The result is that only high-quality code is released, but it is done in a way that automates deployment and shortens the entire deployment process. This is often referred to as “you develop it, you own it,” meaning that if an error, bug, suggestion, or anything else is found in production that needs changing, responsibility falls back to the original developer to update the software.
Another software development process that is often confused with continuous deployment is continuous integration. As with continuous delivery, continuous integration is a separate process from continuous deployment, even if the terms sound similar.
Continuous integration is what software developers use to regularly integrate small portions of the code they are working on with the base code to ensure that it functions properly, integrates effectively, and that any defects may be identified within the smaller code differentials.
Continuous integration helps ensure that small, incremental changes to the code are fully viable long before the ‘final’ product is released. As such, this continuous process often includes daily (or even more frequent) updates. Any change made to the code is automatically integrated back into the main product, making automation a key factor in continuous integration.
Continuous deployment takes this idea one step further. The code release process is automated so when new edits are merged into the code, automated testing immediately takes place. Once the code passes, it can then move quickly into the production environment. Continuous integration can be a beneficial workflow within software development, but it is continuous deployment that pushes changed code from development to production as efficiently as possible.
Continuous deployment can be an advantageous process for software development. Here are five key benefits of continuous deployment:
Possibly the most impactful benefit of continuous deployment is that it improves a business’ capability for quickly releasing the latest updates and code. With continuous deployment, developers are no longer limited to pre-scheduled update windows; they can now update and optimize in-use software in real-time, ensuring shorter development life cycles and more relevant updates.
There is a substantial difference between the lab and the real world, and changes that seem effective in test environments sometimes fail to meet expectations once they are pushed live. As such, one of the most valuable tools for improving applications is timely customer feedback.
The sooner customers can provide their own insights, comments, or criticisms, the more quickly the developer can make the necessary changes. Continuous deployment creates a rapid feedback loop where customers receive updates and can then provide immediate insights. It is an efficient way to more clearly understand both the software and the needs of the customer, without the extended periods of downtime that generally come from soliciting customer feedback.
Automation improves efficiency and productivity for nearly every process. The more steps that can be automated, the quicker a process can be done. Continuous deployment utilizes automation from start to finish; the testing process is automated, as is the actual software deployment. With continuous delivery, a developer needs to approve code, which is a manual process that takes time and can create unnecessary bottlenecks.
With continuous deployment, approval and deployment are fully automated. This allows for a more productive use of time, resources, and available staff, all of which can then be invested in more strategic responsibilities.
There is always a risk with new updates that some of the code might not work properly, even if it passed testing. If developers wait for large, scheduled releases to deploy changes, then any problems that are identified after the fact will be much more difficult to resolve. Continuous deployment makes it easy to release smaller batches of code regularly. Then, if a problem does occur, its smaller size may mean it also has a smaller impact, and it is an easier fix focused on the smaller batch. This means less risk of failure and a reduced likelihood of negatively impacting users.
That said, there is a risk in the sense that there are sometimes impacts that may be outside of a developer's control, allowing them to be overlooked during testing. An example would be a change that causes a minor delay in the code. This may pass testing and not impact the code itself but may have a knock-on effect elsewhere. This is where observability and other external testing of live productions becomes important—with the same feedback loop to the developer.
If a company uses continuous deployment, it is most likely releasing improvements to the software and applications regularly. These regular updates create a culture of customer satisfaction where the needs of the user are constantly being evaluated and met. If improvements only come out every quarter or every year, customers are only seeing the company improve its software occasionally instead of daily or weekly, which can mean that the customer’s expectations are being neglected.
Continuous deployment can improve efficiency and boost productivity. Changes can be deployed quickly, and developers receive feedback just as fast. But continuous deployment works best when it is used with continuous integration. Both continuous integration and continuous deployment automate processes and help developers improve software.
When these two processes are used together, it’s called continuous integration and deployment (CI/CD). CI/CD is a reliable process for getting software products to market quickly, while also implementing new features and fixes regularly and easily. It combines the best of both processes, creating a system where developers can rely on automation to iteratively improve their applications and software on a constant basis. With CI/CD, businesses can create a work environment that attracts high quality developers, reduce the time it takes to develop and deploy applications and updates, improve collaboration across teams and departments, maximize the reliability of their product offering, and ensure a positive customer experience.
While there are benefits to continuous deployment, there are also challenges. A major barrier to implementing continuous deployment is governance. This is particularly important for business-critical applications tightly regulated by established compliance standards or external forces such as government laws.
ITSM Pro from ServiceNow includes connectivity to the DevOps toolchain to allow its change controls to be applied to the toolchain directly. This includes automated change, which is an essential aspect of continuous deployment. ServiceNow empowers businesses with tools to create change records, gather actionable information, and leverage policies to determine whether a change can be approved automatically. This can include decisions based on a comprehensive set of information covering both the pipeline (like test results) and what is known about production in ServiceNow (like incidents). This allows code or configuration changes to be deployed automatically into production with no delay or need for human review.
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