CI/CD are the best practices for DevOps teams throughout an application’s lifecycle. This article explains them in detail.
Table of Contents
- Introduction
- What is the distinction between CI/CD?
- What are some standard tools used for CI/CD?
- Conclusion
Introduction
Continuous integration, delivery, and deployment (CI/CD) is a methodology for rapidly releasing applications to customers. It involves integrating automation into the various phases of application development. Continuous integration, delivery, and deployment are the core concepts of the CI/CD methodology. The problem development and operations teams face when integrating new code is called “integration hell.” CI/CD provides a solution to the problems of integration hell.
CI/CD implements ongoing automation and continuous monitoring throughout the application lifecycle, starting with the integration phase and continuing through testing, delivery, and deployment. An agile development and operations team supports CI/CD with a DevOps or Site Reliability Engineering (SRE) approach. Together, these practices are referred to as the “CI/CD pipeline.”
What is the distinction between CI/CD?
Continuous integration refers to the process of software release, build, and unit testing. It is a process where code changes from multiple contributors are automatically integrated into a single software project. In other words, it is a solution to the problem of simultaneously having too many branches of an application under development, which can lead to conflicts between them.
Continuous Delivery and Continuous Deployment are related terms that are often confused. Both refer to the process of automating additional pipeline stages. However, we can discuss them independently to clarify the extent to which automation occurs.
In continuous delivery, a developer’s application changes are automatically tested for bugs and uploaded to a repository ( such as GitHub or a container registry) where the operations team can deploy them. This improves communication between development and business teams. Continuous delivery ensures that deploying new code requires as little work as possible.
With continuous deployment, a developer’s changes are automatically released to production, where customers can use them. This solves the problem of operations teams being overloaded with manual processes, leading to delays in deploying applications. You can automate the next pipeline stage, building on continuous delivery benefits.
The flow of CI/CD
The CI/CD process has three (3) phases. If any of those stages fail, it notifies the responsible developers about the problem through various communication channels such as email, Slack, etc. If this is not the case, then each successful production deployment will notify the entire team. The phase includes;
The First Phase.
This first phase is the continuous integration phase. The writing and compilation of code occur during this stage of the continuous integration process. Teams integrate new code and work together to build off source code while quickly resolving any conflicts or issues.
The process of continuous integration includes the following;
- Create/Build.
- Evaluate.
- Combine.
The second phase.
Teams test the code at this point. These tests could include integration tests, unit tests, and regression tests. After being reviewed and approved, the codebase is moved to the production environment. This stage is only automated in continuous delivery after the developer has approved it and is fully automated in continuous deployment.
The continuous delivery phase process includes;
- Release Changes to the repository.
The Third phase
In the final step, the modifications are put into production, after which the final product is shipped. In continuous delivery, products or code are first delivered to repositories, waiting for human approval before moving into production or deployment. This step is automated when performing a continuous deployment.
The continuous deployment phase process includes;
- Deploy changes to production
The flow of CI/CD.
Continuous integration.
Having multiple developers working simultaneously on different features of the same application is the ideal situation in contemporary application development. The work can be tedious, manual, and time-intensive if an organization merges all the branching source code. This is because whenever a developer changes an application while working on it alone, it may conflict with other changes made by other developers. The problem can escalate if developers have customized their local IDE instead of agreeing on one cloud-based IDE.
Continuous integration (CI) is a process that allows programmers to merge their code changes into a shared branch, also known as “trunk,” more frequently and reliably. Once a developer merges the changes, the application is automatically built, and unit and integration tests are performed to ensure that the changes haven’t broken the application. This tests everything from classes and functions to the various modules that comprise the entire application. Continuous integration makes fixing bugs quickly and frequently easier if the automated tests find a conflict between newly added and existing code.
Continuous delivery
The first step in the continuous integration (CI) process is to automate software building and testing at the unit and integration levels. The next step is to automate the process of releasing validated code to a repository through continuous deployment. For this reason, you need to ensure that continuous integration, also known as CI, is already built into your development pipeline to have an effective continuous delivery process. Continuous delivery ensures that a code base is always maintained and ready for transfer to a production environment. This is the primary goal of continuous delivery.
Continuous delivery requires test and release automation from code merges to production-ready builds. Once you have completed this step, the operations team can quickly and easily deploy an application to production. This is possible once you have completed all these steps.
Continuous deployment.
Continuous deployment is the final stage of a mature continuous integration and delivery pipeline. Continuous Deployment automates the release of an application to production as an extension of Continuous Delivery. Continuous Deployment is all about well-designed test automation. This is because there is no manual walkthrough in the pipeline stage before production.
In practice, Continuous Deployment means a change a developer makes to a cloud application can go live within minutes of writing the changes (assuming it passes automated testing). Because of this, it’s much easier to get feedback from users and incorporate that feedback on an ongoing basis. Overall, these interconnected CI/CD practices reduce the risk associated with deploying an application. This makes it easier to introduce changes to applications incrementally rather than all at once. However, this requires a significant upfront investment as we need to write automated tests to accommodate multiple testing and release stages in the CI/CD pipeline.
What are some standard tools used for CI/CD?
You can automate the phases of development, deployment, and testing with the assistance of CI/CD tools.
The Jenkins automation server is one of the most popular open-source continuous integration, delivery, and deployment (CI/CD) tools. Jenkins is suitable for everything from a primary continuous integration server to a comprehensive continuous delivery hub.
Other tools include;
- CircleCI: Supports rapid software development and publishing.
- TeamCity: Helps build and deploy different types of projects.
- Bamboo: Automates the management of software application releases, thus creating a continuous delivery pipeline.
- GitLab: A suite of tools for managing different aspects of the software development lifecycle.
- Buildbot: “Python-based CI framework” Buildbot automates compile and test cycles to validate code changes, then rebuilds and tests the tree after every change.
Teams may also consider using various vendors’ managed CI/CD tools with the primary public cloud providers listed above.
Also, we are likely to use traditional CI/CD tools for automating configuration ( such as Ansible, Chef, and Puppet), runtimes for containers ( such as Docker, rkt, and cri-o), and orchestrating containers (Kubernetes) in a variety of CI/CD workflows.
Conclusion
This post presents all the essential aspects of continuous integration, continuous delivery (CD), and continuous deployment (CD). Follow this blog for more releases and updates.
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