4 Key Differences Between Continuous Integration, Delivery, and Deployment
If you’re deciding how to deliver new software or make changes to existing applications, you have several practices to choose from. These practices include continuous integration, continuous delivery, and continuous deployment. No one method is considered the “right” method as each one has different advantages to consider. It comes down to which process best meets the specific needs of your business. There are other deployment processes that you could implement, but these three are particularly effective when it comes to improving your development team’s efficiency.
1. Distinctions in Core Principles
At first glance, these three different approaches may seem very similar. However, there are some key differences to consider when choosing one to implement. This brief breakdown of each core principle will provide you with a better understanding of what each process entails:
Continuous Integration
With continuous integration, the team’s developers will integrate code into a shared repository on a frequent basis (as frequently as several times a day). Every time code is integrated, it can be verified by an automated build and automated tests. This enables the development team to identify and find errors more quickly, making your code more dependable.
Continuous Delivery
Continuous delivery is a process in which developers produce software in short cycles. Through this approach, the software can be manually released at any time. However, automation is still heavily relied upon to test the software and the changes as well as to deliver the changes once deployment has been manually activated (which can be done with the click of a button).
Continuous Deployment
Continuous deployment is very similar to continuous delivery since the software is produced in short cycles. The main difference lies in that deployment is done automatically instead of manually. The goal of continuous deployment is to minimize the time lapses between writing a new line of code and that new line of code being used in production by end-users. It’s why automation is used to update the live application with the new code (as long as it has met the release criteria, of course).
2. Potential Costs of Implementation
Before going into the pros and cons of each practice, it’s worth glancing over the costs of implementation. Consider these cost factors when choosing an approach:
- Costs of continuous deployment – You will need to invest in monitoring tools to ensure that new features and functionality that are delivered to end-users do not result in issues that can diminish the user experience and lower the perceived quality of the software as a whole. You’ll also need to invest in an infrastructure that will make it easy to quickly back out from new features if a defect is revealed following deployment that was missed by your automated tests.
- Costs of continuous delivery – Your tests will need to be capable of covering the majority of your codebase. Although deployment is triggered manually, you will still need to automate the rest of the deployment process. Finally, to prevent incomplete features from affecting the user experience, your developers will need to make use of feature toggles.
- Costs of continuous integration – Adopting a continuous integration approach will require you to write automated tests for every new feature or change that you want to implement. You will also need to set up an integration server that will monitor your main repository as well as run automated tests for every new change submitted. Finally, developers will need to merge their changes frequently.
3. Expected Benefits
There are several benefits to consider when choosing between the three approaches:
- Benefits of continuous integration – Through continuous integration, you’ll avoid a lot of the problems that can come up as a result of waiting for release day to merge code changes into the release branch since these changes are merged back to the main branch as often as possible through continuous integration. The cost of testing is reduced significantly as well since your server should be able to run hundreds of tests within seconds. This also means that your quality assurance team doesn’t have to devote as much time to testing. Finally, all of these tests reduce the number of defects found in the application during production.
- Benefits of continuous deployment – There are two main advantages to the continuous deployment approach. By reducing lead time, you’ll obtain a faster ROI on every new feature you develop, which can reduce your need for big investments. And since you’re able to deliver new features to end-users so quickly, you’ll be able to collect earlier feedback and implement A/B testing to identify user preferences.
- Benefits of continuous delivery – Deploying software will be automated and will be much less complicated. This means that the development team won’t have to spend valuable time prepping for a release. Developers will also be encouraged to be more productive since there will be less pressure regarding decisions for small changes. Finally, like continuous deployment, you can release changes more often, which allows you to accelerate your feedback loop with users. Since you can make the decision to deploy manually, you can deliver your application at the click of a button at any time you want.
4. Drawbacks On The Application
While all three practices have their advantages, they’re not without their disadvantages either. Keep these disadvantages in mind when choosing which approach to adopt:
- Drawbacks of continuous deployment – In a best case scenario, continuous deployment will improve the quality of your software. However, the risk is that your team ends up optimizing for maximum frequency of deployments, which does not necessarily translate to better quality. Faster does always mean better.
- Drawbacks of continuous delivery – Because releases are manually deployed instead of automatically (like continuous deployment), features that are ready for release must go through an approval process. This can result in delays that could hinder the release of the software.
- Drawbacks of continuous integration – A lot of time has to be devoted to building up your test suite and writing test cases. This can be frustrating when your development team would rather spend their time writing code. This means that when implementing a continuous integration approach, it can slow down your team initially. Unfortunately, an unstable test suite can cause a lot of issues that will have to be addressed by your team, slowing down their progress even more. Finally, error messages can become a daily occurrence for larger development teams, and developers may begin ignoring these errors because they are focused on other tasks. You don’t want your team to think a broken build is normal as defects can begin to mount up.
How They Correspond With Each Other
Both continuous delivery and continuous deployment use continuous integration. Continuous deployment is actually a part of continuous delivery as well. They differ in that continuous deployment software releases occur automatically.
Can You Move From Adopting One Practice to Another?
In the long run, it’s worth switching from an older process to a continuous delivery or continuous deployment approach if you haven’t done so already. However, this can pose a challenge. You can’t just switch processes on a whim. Developers will need to relearn the process and they’ll need to write new test cases as well. All of this takes time and effort, which could meet with some internal resistance. You may have developers who work on large portions of code at any given time. Changing to a process in which their tasks are broken up into smaller pieces can take some getting used to.
Which One To Choose?
All three approaches are meant to help speed up the process of delivering new software or changes to software by eliminating bottlenecks that often occur towards the end of the process and can help speed up releases. However, there are minor differences between each process, so consider carefully the pros and cons of each as well as the requirements and potential difficulties involved with switching to a new process. When choosing an approach, make sure that the development team is on board and that everybody fully understands the approach that they are following.
It’s also worth taking stock of where you are in production. If you’re developing a new software and don’t have any end-users yet, then implementing a continuous deployment approach makes sense. You could even release an alpha version via automated deployment to a production without users. However, if you’re deploying changes to an existing app, you should stick with a continuous delivery instead. You’ll want to build up to automating your deployment to production so that you get used to releasing changes on a daily basis.
Finding it difficult to choose which approach to implement for your business? Consult with us today!