CI vs CD: Difference that Enhance Your Development Process

Amazon. Facebook. Google. Netflix. What connects these companies? All have successfully integrated continuous practices into their development processes. Continuous practices are divided into integration, deployment, and delivery. This article will discuss continuous integration vs. continuous delivery and how continuous deployment is related. We’ll wade into the continuous integration vs continuous delivery debate by exploring the business and organizational implications of adopting continuous practices. Then, we’ll compare and contrast, and finally, we’ll talk about how best to implement continuous practices into your processes.

Comparing CI and CD: Similarities and Differences

What’s the difference between CI and CD?

Continuous integration is when developers frequently integrate new code into a shared repository to ensure quality and detect integration issues early. In CI, incorporating the new code triggers an automated testing regimen that analyzes the code update to verify whether it is error-free. If it is, the code progresses to a non-testing stage where a developer decides to move it to production (continuous delivery), or, in the case of continuous deployment, it is automatically sent to production because of automation.

Continuous delivery is also a more automated process than continuous integration. CD builds, tests, and sends code updates through a quality assurance pipeline. At the end of this pipeline, a developer steps in to either approve the update or send it back to be fixed. However, in a continuous deployment scheme, the decision to ultimately produce an update is automated without human intervention.

Ultimately, there are few differences between continuous integration and continuous delivery. They were both designed to improve inefficient development processes and differ only slightly. Below is a table to help you better compare and contrast CI vs. CD. It will also help you better understand the relationship between continuous integration and continuous delivery.

Understanding the Role and Importance of Continuous Integration (CI)

How Continuous Integration (CI) Operates

Many think CI vs. CD is a competition between the two; in reality, they are a dichotomy and complement each other. Even though CI and continuous delivery (CD) are linked, let’s stick with defining CI and then get into defining CD in the next section. First, let’s define continuous integration (CI). In short, CI refers to a process rather than a single act or function. As such, CI occurs at various points along the build process, hence “continuous”; the “integration” refers to when developers deliver their code, and a series of automated QA checks ensures it can be integrated into the codebase without affecting performance or delivery at the user’s end.

Continuous integration is the bridge and the gatekeeper between developers and the codebase. In even simpler terms, you can think of continuous integration as the rehearsal and continuous delivery as the performance. Once QA engineers, or, more usually, automated tests, approve the new code, it is finally merged into the codebase by a developer. Developers and project managers moved to continuous practices, such as CD, to remedy the hiccups in the antiquated, pre-agile software development processes, such as waterfall.

Those hiccups emerged when developers tried to push through immense code updates all at once. In contrast, continuous practices dictate adding more minor code at various points along the build process, reducing the time and effort required to fix bugs. This constant vigilance prevents errors from accumulating, making the codebase more stable and reliable. Of course, continuous integration, as we’ve stated, is only one-half of a much larger process, which invariably takes us to continuous delivery. But let’s explore more about what kind of benefits businesses and software developers can expect with implementing a continuous integration process.

Benefits of Continuous Integration (CI)

A 2014 study by famed computer scientist Walter Brenner aimed to discover more about how businesses and organizations implement continuous integration. Brenner and his co-authors interviewed several executives, primarily in the financial sector, as it is known for always needing innovations to automate processes. Brenner and his team also asked how the executives have shaped and used continuous integration to fit their particular needs and what, if any, benefits or challenges it has produced. The following quotes are a small sample of what they said about CI and the changes to the organizational structure that CI has ushered in.

“We have a CI infrastructure, which has the goal to make the status transparent from start of the project.”

“Really with every check-in […] a unit test runs. Only when these were successful we run load and performance tests automatically. And just then […] the package is created and published […] on a system test environment for acceptance testing.”

“It was a challenge to have automated deployments on the mobile platform as well. […] But now every morning we build the e-banking and deploy on both platforms for test.”

“The development environment with Eclipse, SVN and Jenkins is given. If a developer wants a change, he needs to formulate his request.”

These statements reveal much about CI and the various reasons or motivations businesses and organizations have when assimilating CI into their processes. Transparency, for example, is a considerable benefit of CI. Why is transparency important to the development process? There are several reasons, among them:

• Improved collaboration
• Faster issue identification and resolution
• Enhanced accountability
• Risk mitigation
• Quality assurance

Transparency is not among the differences between continuous integration and continuous delivery because they are both open. CI and CD are intended to give all stakeholders access to a build’s history by recording all changes in a central repository. This transparency came about as a response to the difficulties of making one developer responsible for testing and integrating their contribution to the codebase. With continuous integration, developers work in concert. It’s simpler for them to check each other’s work and find deficiencies. Marshaling all this expertise is another crucial feature of continuous practices: you can deploy talent more effectively across the entire pipeline.

Before we move onto continuous delivery, here are a few more of the benefits of continuous integration:

Improved Code Quality

CI encourages developers to write cleaner, more maintainable code. Automated tests and code reviews help ensure new changes adhere to coding standards. As a result, the overall quality of the codebase improves, leading to fewer bugs and better performance.

Faster Development Cycles

CI streamlines the development process by automating repetitive tasks such as testing and building. This streamlining allows developers to focus on writing code and implementing new features rather than spending time on manual testing and integration. The result is shorter development cycles and faster time-to-market for new releases.

Better Test Coverage

CI encourages automated tests that can run frequently and consistently. This coverage leads to better tests and higher confidence in the codebase. Automated tests can quickly catch regressions and other issues, ensuring new changes do not negatively impact existing functionality.

Understanding Continuous Delivery (CD)

How Continuous Delivery (CD) Functions

To better understand continuous integration, we broke it down into two parts, and we’ll do the same with continuous delivery (CD). Continuous delivery (CD) is an extension of continuous integration. It ensures that the software can be released to production at any time. CD automates the entire build, test, and deployment process. Still, it does not necessarily mean every change is automatically deployed to production. If that were the case, we’d talk about continuous deployment, closely related to continuous delivery, save for one crucial difference.

In continuous delivery, a developer decides whether to push a code update to production, whereas continuous deployment, in contrast, automatically publishes every new change without any human intervention. In summary, CI involves automation in the testing phase after developers build something. In contrast, CD builds, tests, and delivers the software with minimal developer intervention until it is ready for production release.

Benefits of Continuous Delivery (CD)

Understandably, companies worldwide have adopted continuous delivery because of its speed and efficiency, even though many of these same organizations initially resisted it. A 2018 systematic review performed by researchers from the Polytechnique Montréal and the Université du Québec of the existing literature on the problems and solutions associated with continuous delivery and, by extension, continuous deployment found that the CI vs. CD pipeline was a significant concern among organizations. Developers' lack of faith in the pipeline meant they were wary of the entire process. Given the choice between the CI vs. CD pipeline, they opted to stick with their tried-and-true CI, remaining in charge until the testing phase.

However, all these fears were gradually allayed. Developers and companies began to see the potential of continuous delivery and deployment. They reached the same conclusions as the researchers, who found that “continuous practices are all about speed of development.” But they are also more than that. Eventually, developers, project managers, and business leaders found that continuous delivery and deployment significantly increased the ability to send dozens of code updates, sometimes in under ten minutes. Of course, speed is only one benefit of continuous delivery. The other benefits of continuous delivery include:

Faster Time to Market

As mentioned before, for many practitioners, continuous delivery is about speed. CD significantly accelerates the release cycle, allowing companies to quickly bring new features and updates, which is especially vital in competitive markets: being first can make a significant difference. For example, let’s look at Amazon.

Amazon employs continuous delivery practices that enable it to deploy code changes every 11.7 seconds on average. This ability to deploy quickly and frequently has helped Amazon to stay ahead of competitors and continually innovate. The rapid deployment cycles mean that new features, improvements, and bug fixes can be delivered to customers almost immediately after they are ready. This agility has been a critical factor in Amazon’s success and dominance in the e-commerce industry.

Enhanced Collaboration and Transparency

Another plus of continuous delivery that stakeholders often repeat is that CD enhances collaboration and transparency by creating a more streamlined and open development process, reducing intractable bottlenecks, eliminating costly delays, and improving overall efficiency.

A prime example is Google. Google’s engineering teams extensively use continuous delivery practices. The company employs an internal tool called Piper, which hosts the source code of all Google projects. Piper allows developers across different teams and geographies to collaborate wherever they are. The tool’s integration with Google's build and test systems ensures that changes are continuously integrated, tested, and deployed, promoting a culture of transparency and collaboration.

This practice has resulted in:

• Improved Code Quality: With more frequent code reviews and automated testing, issues are identified and resolved early.
• Reduced Time to Resolution: Faster identification and fixing of bugs due to continuous integration and monitoring.
• Higher Team Morale: Teams work more cohesively with clear visibility into the development process and progress.

Continuous Feedback and Improvement

Simply put, continuous delivery allows for continuous feedback. Every developer will tell you this feedback is crucial for ongoing improvement and innovation. Companies can gather user feedback more frequently and make data-driven decisions for future development.

Netflix is a leading example of leveraging CD for continuous feedback and improvement. Netflix’s culture of rapid innovation is powered by its CD pipeline, which allows the company to release new features and updates daily, another stark difference between CI and CD in DevOps. Netflix employs a practice called Chaos Engineering, where they intentionally introduce faults into their system to test its resilience. Combined with CD, this approach ensures that the platform is constantly being tested, improved, and refined based on real-world data and

Best Practices for Implementing CI and CD

Building on the literature cited in this article, we’ve compiled some of the best practices for implementing continuous integration and delivery. Many of the best practices for implementing CI or CD are similar, such as automation, expert CI or CD consultants, specialized CI and CD teams, security, and optimizing testing. However, some best practices apply only to continuous integration or continuous delivery.

Continuous Integration: Best Practices

• Forge a Continuous Integration Path

Before implementing continuous integration, it could help to create a path with a beginning, middle, and end to give your team a clear outline of your goals. Doing this focuses on incremental adoption. Rather than overhauling the entire system, you can begin with what’s known as low-hanging fruits—simple, easy-to-implement practices like setting up automated builds. This approach ensures that you can achieve quick wins and demonstrate the immediate benefits of CI to stakeholders. Once the foundational elements are in place, you can gradually extend the CI system to handle more complex operations. For example, start with basic build automation and then move on to incorporating automated testing and code quality checks.

• Make CI Part of your Mission

In the run-up to implementing CI, you should first integrate a CI mindset into your organization’s values and practices. Once CI is integral to your company’s mission, you’ll ensure its longevity and effectiveness as a practice. To do this, you should create a shared service team dedicated to maintaining CI tools and providing training. This team will act as the backbone of your CI infrastructure, ensuring that all teams are well-supported. By fostering communities of practice, you encourage knowledge sharing and continuous improvement. For example, informal meetups and workshops led by CI thought leaders can inspire team members and keep them engaged with the latest advancements in CI.

• Master Test-Driven Development (TDD)

Mastering Test-Driven Development (TDD) is a cornerstone of effective CI. TDD involves writing tests before implementing the corresponding functionality. This practice ensures that your code meets the desired specifications and is high quality. By alternating between writing tests and implementing functionality, you create a robust safety net that catches errors early in development. For example, writing a test for a new feature before coding ensures it behaves as expected once implemented. TDD improves code quality and makes your codebase more maintainable and manageable to refactor, ultimately leading to more reliable and stable software.

Continuous Delivery: Best Practices

The solutions outlined here were first articulated by Proulx et al. in their systematic literature review, which expounds on the problems and challenges in implementing continuous delivery and deployment. However, other researchers, such as Chen (2017), have articulated similar solutions to solve problems associated with adopting continuous delivery.

These solutions were neither tested nor confirmed. Instead, the authors offered them up in response to what they found to be the most pressing problems with organizations adopting continuous delivery and deployment. As with any new software development practice, a business’s particular needs and real-world conditions usually determine which solution will work the best; these are only a few ways organizations can integrate continuous delivery.

• Assigning an Expert in Continuous Delivery

Proulx et al. and Chen advocate onboarding expert continuous delivery practitioners to boost confidence in the CD pipeline among wary programmers and developers. With a CD expert on board, you’ll have a vocal advocate who emphasizes testing and ensuring adequate coverage and quality. They will also be able to call upon best practices and recommend appropriate tools that are compatible and configured correctly for CD implementation.

• Creating a Dedicated Continuous Delivery Team

Why onboard one expert when you could use a team? If you have the resources to hire a specialized CD team rather than a single expert, you’ll give yourself an enormous advantage. A specialized CD team can handle most of the work related to the CD pipeline. This team acts as a bridge between development and QA, alleviating the burden on the development team. They help integrate and synchronize efforts between these teams and manage tools and environments more effectively.

• Starting with Manageable Components

For the visual learners and engineers on your team, creating a visual representation of the CD pipeline could help them better understand their role in the process. Implementing a visual proof-of-concept could also aid in tracking progress, synchronizing efforts among team members, and ensuring that dependent components are deployed in the correct order.

Applying Continuous Integration and Continuous Delivery at Vodworks

Knowing whether to adopt continuous integration and continuous delivery is a tough decision for any organization to make. Fortunately, Vodworks has years of experience helping companies in various verticals, from gaming and retail to media, telecom, and finance, find the right solution to their development process. Vodworks’ team can analyze and assess your business's shortcomings and decide whether you could benefit from adopting any of the continuous practices described here. Write to us today to discuss your options for optimizing your development process with continuous integration, delivery, and deployment or all three.