What is CI/CD? Continuous Integration und Continuous Delivery explained

What do the terms CI/CD, CI/CD pipeline, CI/CD tools and DevOps mean? In this article you will get a comprehensive explanation of all the terms, concepts and technologies you need to understand in the context of CI/CD.

The Google trend data shows that the search term “CI/CD” is experiencing a surge in popularity.

In modern software development, the terms “CI/CD” and “DevOps” are widely used. However, what do these terminologies signify, and why are they crucial? What is the foundation of this movement, and how can it transform software development?

What is CI/CD?

Continuous Integration (CI) and Continuous Delivery (CD) are crucial concepts in contemporary software development. They establish the foundation for effective and superior software distribution. First, let’s examine the explanations of these terms. If you are unfamiliar with CI/CD, these definitions may appear quite abstract. Nevertheless, by the end of this article, all your queries should be resolved.

What is DevOps

CI/CD and DevOps are closely linked. DevOps is a culture and practice that aims to enhance collaboration and communication between an organisation’s development and operations teams. Its primary objective is to streamline the software development and delivery process, allowing for quicker and more dependable software delivery.

The conventional method of software development and IT operations can foster silos, where developers and operations function independently and have divergent objectives. This can cause delivery delays, quality problems, and disputes. DevOps seeks to bridge these gaps by fostering close collaboration between teams. To this end, various tools, including CI/CD pipelines, are employed.

What is a CI/CD pipeline?

A crucial component of modern software development and DevOps practices is a CI/CD pipeline, also known as a DevOps pipeline. It’s an automated sequence of steps that enables software CI/CD processes, and the central part of an efficient software development and delivery workflow. The structure of a CI/CD pipeline is demonstrated in the given diagram.

The CI/CD pipeline is an automated workflow that covers the entire software development lifecycle from code change to production deployment. The main components and steps of a typical CI/CD pipeline are:

1. Sourcecode: This marks the beginning of the CI/CD pipeline, where developers oversee their code within a version control system such as Git. Commits occur here, representing code modifications that frequently activate the development process via webhooks.
2. Build: After saving the code changes in the repository, the build phase commences. During this phase, the code is transformed into an executable form. This includes creating container images (such as Docker), compiling Java code or building a JavaScript frontend (for example, Vue.js).
3. Test: Automated tests are run at this stage to confirm functionality and to check for any unexpected errors. These tests can take various forms, including unit tests, integration tests and acceptance tests.
4. Manual review: If required, an additional manual check can be implemented to verify that all qualitative requirements have been met. This stage enables the developers or the QA (Quality Assurance) team to scrutinise the code and functionality to ensure that they meet the expectations.
5. Deploy: In the last stage, the software is deployed to the target environment, either automatically or manually. The deployment may involve testing, staging or production environments as per the requirements and setup of the CI/CD pipeline.

However, a CI/CD pipeline can be structured differently than the way described. For instance, additional tests can be conducted and another deployment can occur after the initial deployment. This method is applied when there are separate test and production environments. Your creativity and project requirements are boundless.

The CI/CD pipeline is crucial for implementing DevOps practices and is an essential element of modern software development teams that prioritize efficiency, quality, and agility.

Continuous Delivery vs. Continuous Deployment

Continuous Delivery and Continuous Deployment are two closely related concepts that are essential for automating and speeding up the software delivery process. While they are similar, there are significant distinctions to be noted between them.

Continuous Delivery (CDE in some literature) refers to the automatic deployment of software to the production environment, provided it successfully goes through the development, testing and quality control process. Nevertheless, deployment to the production environment does not occur automatically with CD, as manual intervention is necessary to facilitate software production. This permits a final check and release by the responsible parties.

In contrast, Continuous Deployment involves automatically deploying every code change that passes the development and testing phase to the production environment with no manual intervention. This process is entirely automated, and the software becomes operational within just a few minutes or hours of commit.

The suitability of different approaches and their benefits and drawbacks depend on an organisation’s goals and requirements. Continuous Delivery is well-suited to situations where meticulous testing and software deployment in the production environment are necessary, especially for high-security or compliance-related applications. It offers precise deployment timing control and allows manual reviews to prevent unexpected production problems. Continuous Deployment is ideal for environments that require frequent updates and quick reactions to changes. It speeds up the deployment process and allows for the delivery of new features and bug fixes in near real-time. This results in reduced time-to-market and increased agility. However, in environments with strict compliance requirements or sensitive data, automated deployment may be less suitable due to reduced control.

A practical example of Continuous Delivery could be a financial company that operates an online banking platform. New software versions are automatically deployed to a test environment where they are extensively tested. After successful verification by QA teams, the software is manually transferred to production to ensure that financial transactions are processed securely and without errors. An example of Continuous Deployment would be an e-commerce company using Continuous Deployment for their website. Any code change that successfully passes testing is automatically deployed to production. This allows the company to quickly implement new features and respond to customer feedback to continuously improve the user experience.

Advantages of CI/CD

Implementing a CI/CD pipeline in software development provides several benefits that considerably enhance the development process. Here are some of the crucial advantages of CI/CD:

1. Increasing efficiency in development:
   • CI/CD automates the process of building, testing and deploying, reducing the chances of human error and leaving developers with more time to focus on coding.
   • Faster integration of code changes into the main code branch (typically referred to as the main or master branch) accelerates the development cycle and helps teams respond more swiftly to customer requirements.
2. Higher quality and reliability of the software:
   • CI ensures that code changes are immediately checked for mistakes and conflicts, improving the overall quality of the code.
   • Automated tests in the CI/CD pipeline detect errors early so they can be corrected before they affect the production environment.
3. Faster time to market:
   • Automating deployment and testing results in faster time-to-market for products and features, because new versions of the software can be promptly put into production.
   • Moreover, agile development methods can be more proficiently utilised since new features can be deployed in shorter iterations.
4. Scalability and flexibility:
   • CI/CD pipelines are highly scalable and adaptable to the needs and requirements of projects of any size.
   • They can support a range of development environments and infrastructures.
5. Automatic compliance and security:
   • Continuous Integration and Continuous Deployment (CI/CD) allows for the incorporation of security and compliance examinations during software deployment to guarantee that all requirements are met.
   • Automated monitoring and enforcement of policies and security checks is feasible.

Despite the numerous benefits of CI/CD pipelines, there are also drawbacks such as the intricate setup and upkeep of these pipelines and the necessity to configure automated tests and checks accurately for effective deployment. Therefore, there are additional articles and tutorials on DevOps available on this blog.

What are CI/CD tools and which one should I use?

There are numerous CI/CD tools available in the market. This document provides a concise summary of these tools, along with selection criteria to assist in selecting the appropriate tool.

Overview of known CI/CD tools

• Jenkins: Jenkins is renowned as being one of the most popular and extensively used open source CI/CD tools. It provides significant flexibility and customization options to establish intricate CI/CD pipelines. Jenkins boasts a vast community and an expansive suite of plugins, catering to almost any demand.
• Travis CI: Travis CI is a cloud-based CI/CD tool that focuses on swift and straightforward integration, making it especially fitting for open source initiatives. It enables uncomplicated configuration via a .travis.yml file located in the repository.
• CircleCI: CircleCI is a cloud-based platform for CI/CD, prioritising speed and reliability. It provides the capability to run builds in containers and is ideal for projects with intricate dependencies.
• GitLab CI/CD: GitLab CI/CD is closely integrated with the GitLab platform and delivers a seamless experience for continuous integration and continuous deployment. It includes built-in support for container orchestration and Kubernetes.
• Argo Workflows: Argo Workflows is a freely available workflow manager created for Kubernetes and containerized environments.
• GitHub Actions: GitHub Actions is a CI/CD integration that is directly integrated into the GitHub platform. This enables effortless automation of workflows and simple integration into GitHub repositories. Discover how to establish a CI/CD pipeline with Plesk and GitHub Actions.
• Azure DevOps: Azure DevOps is a complete development platform by Microsoft that also offers CI/CD functionalities. It makes it effortless to merge with Azure services.
• AWS CodePipeline: AWS CodePipeline is an AWS-hosted service that enables automated build and deployment processes in AWS environments, known as CI/CD.
• AWS CodeCatalyst: AWS CodeCatalyst is a comprehensive CI/CD tool from AWS that combines pre-made templates and numerous project management tools.
• TeamCity: TeamCity is a CI/CD tool developed by JetBrains, renowned for its simple usability and seamless integration with development environments like IntelliJ IDEA.
• Bamboo: Bamboo is an Atlassian CI/CD tool that offers seamless integration with other Atlassian merchandise, including Jira and Bitbucket.

Selection criteria for the right tool

The choice of the right CI/CD tool depends on the individual requirements of the project. Here are some selection criteria that can help with the decision:

• Scalability: As your project expands, ensure that the tool you select can manage the greater workload.
• Integration: Check how well the tool is integrated with your existing development and deployment workflows. Consider the simplicity of the tool’s interface and the proficiency required to operate the tool before choosing. It is critical to consider a tool that can integrate with your version control system and other development tools.
• Server environment: Additionally, it is crucial to note that some tools, such as AWS CodePipeline, are designed to run solely in AWS, making it challenging to deploy them in other environments (e.g. Google Cloud).
• Ease of Use: The tool’s user-friendliness and effortless pipeline configuration can substantially hasten the development process.
• Cost: Be mindful of expenses, notably if you employ a hosted CI/CD tool such as AWS CodePipeline or Azure DevOps. Numerous providers offer generous free quotas that meet most use cases.

Conclusion: CI/CD

CI/CD pipelines drive the transformation of software development rather than existing merely as tools. These pipelines enable faster development, shorter release cycles, and quicker time-to-market for software products by automating code integration, continuous testing, and seamless deployment. The significance of CI/CD for contemporary businesses cannot be disputed, particularly as it fosters a culture of collaboration and continuous improvement beyond automation. Developers, quality assurance, and operations teams collaborate to craft top-notch software that satisfies market demands.

Regarding future developments, CI/CD is expected to assume an even more central position. As cybersecurity becomes an increasing challenge, the integration of security and compliance testing will become more important. Additionally, the efficiency of CI/CD pipelines will be enhanced through the application of artificial intelligence and machine learning.

In summary, Continuous Integration and Continuous Deployment (CI/CD) is more than just a tool – it represents a paradigm shift in software development. It allows companies to enhance their agility, accelerate product launches, and enhance quality. Organisations that implement CI/CD effectively possess a greater chance to prosper in a digital world and offer inventive solutions.