Differentiating between Continuous Integration, Continuous Delivery, and Continuous Deployment is an integral part of today’s software development industry. However, these three terms have been misconstrued and confused with one another, leading to the misuse of these techniques. There are numerous resources that continue to showcase how different each process is and also discuss how they coincide with one another.
Continuous Integration is the process where a specific code is integrated into a mainline code base. CI is a common process that implemented in nearly every scenario today. It’s a simple method that merely requires the user to utilize the right tools. Continuous Delivery, on the other hand, is a bit more complex than its counterpart. CD refers to the processes that occur after the code is integrated for app changes – testing, staging, and deploying code. Now, as of yet, there is not a versatile tool that can perform all these methods at once, leaving the user to take numerous steps to achieve success. Remember, these processes take on a different form, depending on the type of app that is created along with the team’s approach. While these two terms share the word “continuous” in their title, they have little to do with one another, which is why it’s crucial that developers understand when to utilize one over the other.
Furthermore, it’s mandatory that all developers differentiate the terms to ensure the process steers away from errors. For instance, if a developer was to set up a CI server to integrate a variety of code changes, he or she must realize that CD is not being performed. As a matter of fact, the developer is solely using a CI server. In order to reach CD, the developer must organize the software testing, staging, and deployment processes to automate them and ensure they are continuous. To perform this, the developer cannot simply turn on a tool and call it a day. Rather, he or she must go through a variety of steps to ensure every aspect is covered.
Continuous Deployment refers to the release of code once the production is completed. Now, there is no testing or batching in the production phase – all of this is done prior to the merging stage. The production branch is stable (as it should be) and ready to be deployed by an automated process. After the deploy, logs will be inspected to determine if any key metrics have been affected in a positive or negative way. Some examples of the metrics include response time, traffic, or revenue. Continuous Deployment works alongside Continuous Integration and Continuous Delivery to ensure that there are no errors on the day of release and every batch of work is fed to the next step.
Understanding how each process works is a must-do for every developer. Since each app that is created must go through a series of steps before releasing, knowing how each process (CI, CD, and CD) functions and when it is utilized will eliminate the confusion between one another.