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What is CI/CD? Continuous Integration & Delivery Explained



what is ci and cd

Introducing CI/CD is a way to leverage automation in the agile product development process. CI/CD stands for — Continuous Integration, Continuous Delivery, and Continuous Deployment. This model forms an integral part of adopting the DevOps culture, which, in turn, aims at ensuring faster time to market and customer satisfaction.

The CI/CD loop is similar to a factory set up where automated machines assemble and pack items (integration), seal the package, and make it ready for transportation (deliver). Finally, the transport system delivers packages to warehouses/shops (deploy).

According to Dzone’s State of CI and CD trend report, DevOps culture-driven organizations are increasingly using the model to create SaaS products.

number of years organizations have been using ci/cd according to dzone | what is ci and cd

Additionally, as per GitLab’s DevSecOps survey, a rapid elevation was observed in automation, release cadences, continuous deployments, and security postures, growing dependence on next-gen technologies like AI, ML, and so on.

Here’s a comprehensive guide to help you understand what CI CD means and how it will benefit your team and your product.

The Relevance of CI/CD

The general process of the software development cycle involves — multiple developers working on different features at the same time. Now, if the disintegrated code were to be merged one day, it could be manually exhausting, time-consuming, messy, and the functioning of the entire system could fall off track.

Moreover, if the developers are working in independent teams, their code might not sync well with the other team’s code — leading to a more hay-wired setup.

It is similar to postponing your meetings each day and aligning them together on a particular day and, in turn, increasing your burden while reducing your enthusiasm and productivity.

With continuous integration (CI), the code is merged to the mainline (shared repository) frequently, often multiple times in a day. The changes then go through a series of automatic software tests (for example — unit tests and integration tests) to validate the application’s wholeness and integrity.

Once the changes are validated and everything is in place and working, continuous delivery ensures that the new workable system is added to the mainline. Finally, continuous deployment steps in, i.e., the new version of the software is made available to the end-users.

With CI/CD, you can align your meetings regularly so that you can tend to the smaller issues regularly, rather than the “all at once” approach.

As per a recent report by Statista, besides containers technology, CI/CD is amongst the technologies that OpenStack users wish to adopt.

What is CI/CD? — Technical Definition

Where CI has a constant implication, i.e., continuous integration, CD can mean two different processes, i.e., continuous delivery and continuous deployment. Here is what each of them means:

a process flow demonstration | what is ci and cd

1. What is Continuous Integration (CI)

Continuous integration implies that new user stories in agile are built, tested, and integrated into the existing system. Maintaining the wholeness and the integrity of the software — is the objective of the CI process. To implement continuous integration in Agile, you must push the changes to the larger system multiple times (at least daily).

2. What is Continuous Delivery (CD)

Continuous delivery implies that the new user stories are automatically tested, sent back for bug fixtures if any, automatically retested, and sent to a central repository. The new features can then be released to the production environment.

continuous delivery stat - net solutions agile product development report | what is ci and cd

Continuous delivery aims to ensure that every change to the code can be deployed to a live environment and is bug-free, efficient, effective, workable, and reliable.

According to a recent report, the Continuous Delivery market has enumerated a CAGR of 19.75% for the forecast period 2021 – 2026.

3. What is Continuous Deployment (CD)?

Continuous deployment implies that the new user stories present in a central repository are automatically released, i.e., making the newly added features available to the end-users.

Continuous deployment is closely related to continuous integration and refers to the release into the production of software that passes the automated tests. — Jez Humble & David Farley, Author of Continuous Delivery

This tweet by Martin Fowler nicely sums up the crux of continuous delivery and continuous deployment.

What is CI/CD Pipeline?

The CI/CD pipeline is a series of automated steps and processes that are followed to deliver new features to the end-users. This pipeline is about building, testing, merging, adding the latest version to a central repository, and releasing it. CI/CD Pipeline follows the DevOps approach to accomplish the mentioned goal.

Continuous integration and continuous delivery are vital yet distinct components of the CI/CD pipeline. Continuous integration comprises continuous merging of code in the repository along with automated building and continuous testing of the builds. This is the main advantage of using continuous integration to produce builds while continuous delivery focuses on the rest of the process.

What are the different stages of the CI/CD pipeline?

A CI/CD pipeline includes four stages:

  • Source stage (where the CI/CD pipeline gets triggered by a code repository)
  • Build stage (where the source code and its repositories are merged)
  • Test stage (automated tests are executed for validating the correctness of the code)
  • Deploy stage (the final stage where the product goes live)

What is CI/CD Process?

Here’s an analogy to help understand the CI/CD workflow in detail. Assume you have two SaaS developers on the team who have been working remotely on the code for the same SaaS application.

The process they follow is:

Step 1

Adding the respective code fragment to a central repository daily.

Step 2

The code automatically shifts to the CI server where — build, test, and integration occurs for each of the code fragments.

This step usually involves unit tests (where individual components of the larger code are continuously tested) to ensure that codes provided by both the developers flawlessly fit into the existing software product.

Step 3

Next, acceptance tests are run by the developers, followed by staging the integrated software in an environment similar to that of production. This is known as the deployment pipeline, which consists of — development environment, a testing environment, and a staging environment.

Where deployment to staging is automatic, deployment to production is manually executed. Post the manual deployment to production; automated smoke tests are conducted, i.e., a test that checks the deployed software’s stability.

If the test fails at any stage of the deployment pipeline, it will not move to the next stage. The developers can easily detect the issue and re-iterate through the deployment pipeline to ensure continuous delivery.

Step 4

Finally, the code that both the developers create is automatically sent to production. This is only possible when the respective code successfully passes through continuous integration and continuous delivery processes.

what is continuous delivery

Cost of Implementing CI/CD Pipeline

The cost of implementing a CI/CD pipeline is high as you are introducing automation to the system. The upfront costs need to be looked into beforehand. Here are some resources you need for a successful implementation of the CI/CD pipeline:

  • Writing and running automated deployment tests
  • Investing in CI/CD tools
  • Access to the CI server

What Tools Should You use for CI/CD?

Here is a collaborative list of ten common CI/CD tools available in the market.

Popular CI/CD Tools
Tool
Purpose
1. Jenkins Open-source automation server for facilitating CI, CD, and the other CD
2. SonarQube An open-source tool for continuous code analysis that helps in ensuring source code’s higher quality
3. Spinnaker A multi-cloud continuous delivery platform developed by Netflix
4. GoCD Helps automate build, test, and release cycles
5. Concourse An open-source platform for CI/CD that automates tasks
6. AzureDevOps Offers automatic build, testing, and release management
7. CircleCI Is an enterprise-level solution for automatic implementation of CI and CD
8. Tekton Pipelines Open-source project for automating CI/CD pipelines
9. AWS CodeBuild Fully managed continuous integration service
10. Screwdriver An open-source platform for facilitating continuous delivery

Best CI/CD Practices

Jez Humble introduced a “Continuous Integration Certification” test that acts as a KPI (key performance indicator) for organizations implementing CI/CD. Based on the test, here are some of the best practices that ensure the success of your CI/CD pipeline:

  • Every developer adds the smaller fragment of code to the central repository at least daily
  • Every source code addition leads to automated testing and automated integration ceremonies
  • If the automated testing shows some error, the bug is detected and fixed within ten minutes

What are the Benefits of CI CD

Automation is the idea behind implementing CI/CD. The processes help ensure minimal sign-offs and manual authentications — that otherwise hurt the lead time.

The major benefits of CI/CD are mentioned below:

1. Increased Focus on Core Responsibilities

Both the development and the operations team (DevOps) can increasingly focus on their core competencies. Moreover, the teams would not have to wait for manual sign-offs between them for executing integration, delivery, and deployment — as everything will be automated.

2. Development of an Agile Mindset

development of an agile mindset | benefits of ci and cd

When the developers will contribute to the software code daily, and the bugs will have to be fixed on the go — the speed of execution will automatically increase. CI/CD is the best way to promote the agile mindset within the development and operations team.

P.S. – Before embracing Agile mindset, it is important to leverage Product mindset over Project mindset too.

3. Better Code Quality

With code being added to the central repository almost every day, a broken system’s chances get reduced. These everyday additions make continuous integration and delivery easier as there are small code fragments to deal with, thus less probability of emerging anti-patterns and bugs.

4. Ensures Faster Time to Market

ensures faster time to market | benefits of ci and cd

The CI/CD pipeline ensures that automation takes over the integration, delivery, and deployment process, which ]further leads to — faster time to market. The main objective of CI/CD is to reduce the time to market that otherwise used to take years due to broken processes and minimal collaboration between development and operations.

5. Helps Maintain Shipping Cadence

With continuous integration, delivery, and deployment — the code can be released to the end-users in a timely manner. The timely deliveries mean that the time between the MVP release and the fully-fledged product will get reduced. This, in turn, will further help in gathering feedback early and scheduling product refinement.

FAQs

1. What are the examples of CI/CD pipelines?

  • Source Code Control
  • Continuous integration
  • Deploy code to UAT
  • Deploy to production

2. What is CI v/s CD?

Continuous Integration (CI) is the process to integrate code mainline codebase. At the same time, CD can mean Continuous Delivery or Continuous Deployment.

3. Which are the most popular CI/CD tools?

  • Bamboo
  • Jenkins
  • CircleCI

4. What is the CI/CD pipeline KPI?

  • Deployment Time
  • Development Frequency
  • Change Lead Time
  • Change Failure Rate
  • MTTR vs. MTTF

5. How does CI/CD pipeline help IT specialists?

  • Enabling IT specialists to pull code from version control and execute software build
  • Moving code to target computing environment
  • Enhancing reliability
  • Providing log data and alerts on the delivery state
  • Verifying code changes before moving forward, minimizing the scope of defects ending up in production

6. What is one component of the continuous delivery pipeline?

The pipeline has four elements:

  • Continuous Exploration (CE)
  • Continuous Integration (CI)
  • Continuous Deployment (CD)
  • Release on Demand

7. What are three advantages of continuous integration?

The major three continuous integration benefits include:

  • Risk mitigation
  • Reduced overhead
  • Consistency of build process

Conclusion

Implementing CI/CD in your product development setup should be a priority to ensure faster build, delivery, and deployment cycles. It helps automate the tasks at hand that lead to the availability of the software and its varied versions to the end-users.

The above article covers the basics of CI/CD, tools for automating the tasks, and the advantages of CI/CD for your business. Now that we know more about CI/CD, we can say that practicing continuous (integration, delivery, and deployment) should be considered wholeheartedly to be tagged as an implementer of DevOps culture.

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Rajnish Kumar Sharma

About the Author

Rajnish Kumar Sharma is a Project Lead at Net Solutions and is a part of Continuous Integration (CI), Continuous Delivery (CD), and security initiatives. Apart from exploring new technologies and handling technical challenges, Rajnish is equally passionate about movies, cricket, and traveling.

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