GUIDE 2022

Continuous Integration vs Continuous Delivery: What’s the Difference?

Would you like to know the difference between continuous integration and continuous development? Well, you’re in the right place.

The software development industry is facing an ever-growing demand for delivering high-quality and high-performing software fast and efficiently. To respond to these challenges, software developers are implementing a variety of practices and approaches, such as agile methodologies, code reviews, refactoring, and to name a few. Continuous integration (CI) and continuous delivery (CD) are development practices that highly agile teams adopt. 

The two approaches aim to streamline the process of software development and deployment. Their effectiveness makes them part of the mandatory arsenal and skills of a SaaS product manager. So what are continuous integration and continuous delivery?

In this article, we discuss these mainstream practices and the differences between them. You’ll find out why you should consider adopting them in your team development activities. We also share the best CI/CD tools that will help you become a successful SaaS product manager and make your journey seamless and hassle-free. 

Let’s dive right in.

 

Continuous integration (CI) vs Continuous Delivery (CD)

CI and CD are closely related to each other. These are methods that facilitate the frequent delivery of high-quality bug-free programs to clients. They are particularly suitable for the process of agile development and intensive collaboration across multiple developers working on the different features of the same application at the same time.

As a product manager, ensuring stress-free and frictionless product releases is your principal goal. To achieve it, you must create a product roadmap in line with the CI and CD approach you’re adopting. 

Having thus specified the steps to reaching product short-term and long-term objectives, it’s much easier to deliver applications and other software products on time and to your customer requirements. So, let’s look closely at continuous integration and continuous delivery and compare the two practices and their benefits.  

What is Continuous Integration?

Merging all of the branching source code together is a tedious and time-consuming task. CI focuses on this aspect of the process and refers to a stage of the development cycle when portions written by individual developers are integrated together. Typically, this means merging code, building the application, and conducting basic tests.

Continuous integration allows developers to regularly merge their code modifications into a common branch or “trunk.” Merging takes place in short intervals, daily or even more frequently, to ensure that any potential issues are detected and solved instantly.

The automated app build and the various levels of testing validate the code changes made by each developer and make sure they haven’t damaged the app’s functionality and operability. CI streamlines the process of fixing any bugs and incompatibilities between the existing and the newly written code in case the automated testing registers potential issues.

What are the Continuous Integration Steps?

Depending on the particular project, programming language, and solutions used, continuous integration workflows are different. The following steps, however, are common for all cases:

  1. Developers commit daily to a shared repository
  2. Every commit automatically triggers a build and test 
  3. In case of a build or test failure, the code is repaired immediately

So, continuous integration enables developers to collaborate in small iterations and implement automated build and test processes. Note that build testing must follow the best agile testing practices to further promote fast and reliable software development.

What are the Benefits of Continuous Integration?

Continuous integration brings lots of advantages to your team. Here are some of them:

  • Increased productivity of the software development team due to the faster feedback loop
  • Early capturing of regressions
  • Prompt fixing of failures, which helps avoid context switching as developers deal with the specific issues before going on with the next feature or product
  • Easy build of the app and testing due to the automation of these two processes
  • Enhanced software quality and application reliability as a result of all the benefits above

Now that you know why you need to adopt continuous integration, let’s turn to the next important question.

How can you Adopt Continuous Integration?

There are several steps you need to take to incorporate continuous integration into your software development cycle.

  • Set up the service that runs this test automatically for each push to the main repository. 
  • Make it a routine process for all your employees to adapt. 
  • Fix builds when they break down. 
  • Write tests with each new project implemented.

Having looked at continuous integration, it’s time to move on to the next important concept.

What is Continuous Delivery?

This is a DevOps practice that follows the automation of the building and testing that continuous integration introduces. CD involves the automated release of the tested and validated code to a repository, such as a container registry or GitHub. So, there’s a codebase ready for deployment to a production environment, which actually requires a manual step.

At the end of the continuous development stage, the operations team can deploy the application to production easily. It also ensures transparency and reliable communication between the development and the business team.

What are Continuous Delivery Steps?

The stages in the continuous delivery pipeline depend on the architecture of the product passing through the pipeline. In general, a CD pipeline works in the following way:

  1. Developers submit commits or small incremental batches of commits daily to a shared repository
  2. For every commit, a build is automatically created  and tested 
  3. If the automated tests fail, the issues are fixed immediately
  4. The functional and bug-free code is automatically released to a repository and is ready for deployment to production

Note that the first three steps constitute a CI workflow. Also, in the continuous delivery pipeline, the deployment to production requires a manual gate and a manual approval process. In fact, this distinguishes continuous delivery from continuous deployment, which goes beyond continuous integration and continuous delivery and requires no human attendance to handle the product release.

Benefits of Continuous Delivery

Continuous delivery drives automation further, including the software release process. This brings in the following advantages:

  • Easy, fast, and secure software release
  • Increased productivity freeing teams from manual tasks
  • Early detection of bugs and fixing them
  • Shorter feedback circle due to the frequent software release
  • Reduced pressure on making decisions as changes are applied, committed, and tested in small batches
  • Reduced time to market

How can you Adopt Continuous Delivery?

Continuous delivery builds on top of continuous integration. So, the automation of builds, tests, and quality assurance must be in place to provide the basis for automating the next stages of software release. 

How are Continuous Integration and Continuous Delivery to the Production Environment Related?

As we mentioned earlier, CI forms the initial part of the CD pipeline. Continuous delivery is a logical evolution of continuous integration, introducing automation to the next step of the software development cycle. 

 

How to Move from Continuous Integration to Continuous Delivery, to Continuous Deployment

Once you’ve adopted continuous integration, you can go for continuous delivery whether you’ve just started developing a new app or you’re working on an application that has already gone live and acquired users. What’s the best way to go around?

Moving from CI to CD with a new Project

When you begin a new project with no existing users, it is easy to deploy each commit to the production environment. You adopt continuous delivery, automating deployment and releasing an alpha version of your app without onboarding users. By enhancing the test procedures and running the continuous delivery before officially launching your software product, you’ll ensure that the seamless process is in place before going live.

Moving from CI to CD with an Existing Application

Going to continuous delivery is slower with an existing application that is already in use. Start by automating unit tests and code releases. Then, docs on the more complicated end-to-end system, performance, compliance, and acceptance tests. In this way, you’ll avoid stopping deployment periodically for adjusting release.

Upon implementing CI and CD, move on to adopting continuous deployment, which involves automation of the end-to-end cycle including deployment.

Best CI/CD tools

Continuous integration and delivery tools help create pipelines for standard release processes. Here are some of the best tools that facilitate software development, testing, and deployment.

Jenkins: an open-source on-premises continuous integration server that helps achieve continuous integration and delivery. It features a fast development cycle, builds and tests code multiple times a day, and deploys successful builds. Other open-source tools you may want to consider are Concourse, GoCD, and Spinnaker suitable for multi-cloud environments

Bitbucket Pipelines: a CI tool that automates builds and tests and readily integrates into Atlassian’s cloud version control system Bitbucket

CircleCi: a flexible CI tool that supports many programming languages, such as C++, Python, JavaScript, NET, Ruby, and PHP. It’s fast-performing and allows build environment selection

AWS CodePipeline: a tool that automates entire release pipelines. It interfaces with other AWS products and easily integrates with other third-party solutions. Other public cloud providers that offer CI/CD tools include Atlassian Bamboo, GitLab, and many more.

 

Continuous Integration vs Continuous Delivery: Key Takeaways

The agile development practice has become a norm, which requires acquiring agile developer skills and traits. To do so, you need to automate deployment and ensure reliable software releases.

CI and CD are approaches that help achieve a fully automated process in your deployment pipeline. Automating build and integration tests, continuous software delivery, and deployment automation are steps to improving the time-effectiveness, quality, and compatibility of your product. This is what will enable you to stay on top of the competition and consistently deliver software that exceeds your client’s expectations.

 

Conclusion

Continuous integration is the source code versioning that takes place as soon as the programmer checks in and aims to automate building and testing. Continuous delivery focuses on automating the entire software release process up to deployment. The code is continuously delivered until the responsible DevOps specialist considers it ready to deploy to the production environment. With continuous deployment, developers commit directly to production, and all steps are automated.

With continuous integration, developers submit continuous merging requests. In a continuous delivery workflow, the development team commits code that is then batched for release, provided it passes the pipeline without failing any of the tests. 

The two approaches differ in the testing process as well. Continuous integration applies unit tests and static code analysis to identify coding errors and security holes. 

Continuous delivery uses system, performance, compliance, and user acceptance testing. The goal of this process is to validate the software and the end-to-end business flow and to confirm that the application meets the client’s requirements and is functional, reliable, and stable.

Josh Fechter
Josh Fechter is the co-founder of Product HQ, founder of Technical Writer HQ, and founder and head of product of Squibler. You can connect with him on LinkedIn here.