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Continuous Integration and Delivery Definition

7.06.2021
Continuous Integration and Delivery Definition
Continuous Integration and Delivery Definition
DevOps has been a highly anticipated goal for many organizations over the years. From startups to Fortune 500 companies, businesses of all kinds are rushing to enhance the velocity and quality of software development. CI/CD tools may be precisely the means for that.

Companies recognized the need to improve their development workflow many years ago. Due to the COVID-19 pandemic, all DevOps and CI/CD implementation times have been shortened.

CI/CD: Quality Code Pipeline

In the modern economy, the use of digital tools in business decisions plays a vital role. As the entanglement of high-tech platforms grows, the continuity of critical IT systems is becoming an essential factor. This trend has also affected software development. It is not uncommon for developers to take responsibility for responding to changes in the markets, deploying new functionality and changes in the real environment as soon as possible.

IT managers are committed to providing customers with stable, reliable and secure IT services while making it difficult or impossible to make any changes that endanger production. In such a situation, the developers and the IT managers are pursuing completely different goals and have different incentives. In such a situation, a new approach is a must.

The ability to continuously test and submit code at the programming stage allows programmers to create faster and higher quality turnkey solutions. Continuous merging of the program code into a major fork and checking the results outline the idea of CI/CD. Grady Booch proposed it back in 1991, but it took years for the public to credit it.
source: Techtarget

The tenet of the CI/CD process is similar to a pipeline. It integrates and monitors every development phase: from programming to product release.

It embodies the ideology of uniting software development and operation (DevOps) and complies with the basic Agile rules in terms of recommendations for utilizing automated testing to debug software quickly.

Agile brings customers and developers closer, DevOps eliminates the barriers between programmers and managers. What about CI/CD? It is the embodiment of DevOps in practice.
What is Continuous Integration?
The central repository branch usually contains release-ready code. The term "branch" is used in version control systems (like Git) and means duplication of the codebase with concurrent changes. Continuous integration avoids merge conflicts, which is a clear advantage.

Merge conflicts occur when devs try to merge code into a single branch. CI integrates changes multiple times to prevent a programmer from messing up someone else's code. Due to regular updates, other programmers can always use fresh code in their development environment.
source: mindtheproduct
What is Continuous Delivery?
Continuous delivery tools make the process of building, testing, and releasing software faster and more frequent. This technique consists of a chain of checks: they must all be satisfied, or the code won't be released. For example, before releasing the next version, the program must pass all tests without errors or warnings. This helps make updates more consistent and reliable.

With continuous delivery pipelines, merging or saving code to the master branch will initiate the building of the site. This process can save time by eliminating the unnecessary manual deployment step in the staging environment. Another benefit is that developers can deploy the code only if all tests are passed successfully - this reduces the likelihood of an inoperative application.

With CD, we no longer have to waste time building and deploying staging environments. This process will be performed automatically once a day.
source: mindtheproduct

What is a CI/CD pipeline?

The major goal of the CI/CD pipeline is the automation of software release processes. The pipeline's major tasks are generating code, conducting tests, and deploying new versions of apps securely. In the CI/CD pipeline, developers write abstract code according to technical specifications and instantly test it on their own. So the result largely depends on the programmers.
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    CI/CD Basic Principles

    Thanks to the CI/CD environment, responsibilities are evenly and fairly distributed among all team members. Participants in the development process and consumers of the finished project share responsibility for each stage of the product life cycle:

    • developers and designers develop business logic and also provide a positive user experience with the finished system
    • quality engineers introduce end-to-end functionality and acceptance testing
    • engineers responsible for DevOps continuous integration organize the logistics of the code
    • Users provide feedback on the results of using the system.

    Each group of participants in the CI/CD process minimizes possible risks when the product passes through the stages of the life cycle:

    • control of the business logic integrity
    • user experience (UX)
    • data storage and processing optimization/migration, etc.

      CI/CD Platform Deployment

      The CI/CD process of platform deployment goes through the following stages:

      • Coding. Each of the developers writes the code for their module, conducts manual testing, and then merges the result of their work with the current version of the project's main branch. For version control, the Git system is the best option. When team members publish their module code to the central unit, the next phase begins.

      • Assembly. The version control system (VCS) starts automatic building and testing of the project. Usually, the team configures triggers for the start of the build individually (committing changes in the main branch, building on a schedule, on-demand, etc.) This is where Jenkins (or a similar product) comes into play and automates the build.

      • Manual testing. When the continuous integration system has successfully verified the performance of the test version, the code is sent to the testers for manual verification. At this stage, the test build is assigned a candidate number for further product release.

      • Release. Manual testing fixes the build and increments the final candidate version number (for instance, version 1.0.0-1 becomes version 1.0.0-2). The developers then release a version of the code to the client (for instance, version 1.0.0) and the next phase of the cycle begins.

      • Deployment. At this point, the system automatically sends a working version of the client's product to the developer's production servers. The client can interact with the program and get acquainted with its functionality directly through the ready-made interface and cloud services.

      • Support and monitoring. End users get started with the product. The development team maintains it and analyzes the user experience.

      • Planning. Based on the user experience, the company receives requests for new product features and draws up an improvement plan. The loop closes and proceeds to the initial stage - writing the code. A new iteration of CI/CD development begins.

      CI/CD Pros and Cons

      When all of the developers are working on small tasks in the mainstream, or everyone is working off-main on short-lived feature branches that are regularly merged into mainstream, and when the mainstream is constantly maintained, ready to deploy, and we can make code releases on-demand at the push of a button during normal business hours - we do continuous delivery. When developers make regression errors, including defects, performance issues, security issues, and outages, they get quick feedback. When such problems are discovered, they are immediately fixed so that the main branch is always ready for deployment.

      Continuous deployment is convenient primarily in the context of web services provided over the Internet. However, continuous delivery can be applied in almost any context where we want high-quality deployments and releases that can be quickly executed and deliver highly predictable, low-risk results, including embedded systems, off-the-shelf commercial components, and mobile applications.

      At Amazon and Google, most teams practice continuous delivery, although some are continuous deployment — there are significant differences between teams in how often they deploy code and how they deploy it. Teams have the right to choose how to deploy based on the risks they manage. For example, the Google App Engine team often deploys once a day, while Google Search deploys several times a week.
      source: Google

      CI/CD practices are not that popular for nothing. They have a lot of benefits:

      • A fast feedback loop allows you to check for changes in code immediately. Without constant checks, it takes much longer to detect errors. In this case, bugs can occur after the product is started, or there can be multiple "pending" bugs in one release.

      • CI tools help you quickly find the root cause of defects for each commit, enabling early identification and remediation of errors. The CI/CD platform helps not only to increase the speed of testing but also to provide the end-user with new functions in such a way that when an error is found, it is always possible to either quickly fix it or "rollback" the solution iteration.

      • The method enables prompt releases of new product functionalities (work with customer requests).

      • The product's quality is enhanced by parallel testing of the functional blocks of the future system. Bottlenecks and tipping points are identified and addressed early in the cycle.

      • Devs receive a pool of code alternatives that optimize the resource costs for solving the problem (by automating the initial testing of functionality).
      As good as a CI/CD pipeline is, if you don't have any related experience, you can face many dangers along the way. Project managers mistakenly accept this methodology as a panacea and strive to incorporate it into all their designs. A lack of expertise leads to complications when working on the company's IT products.

      It is necessary to think over the organization of the interaction between project teams since accurate execution of CI/CD commands is closely linked with the human factor. Engineers, scrum specialists, analysts, and dev teams must work in a single environment with adequate leadership and project management.

      CI/CD Pipeline Tools

      Software developers use various tools to automate testing and deliver the code of their projects to end-users. One of the most powerful is GitLab. It allows you to manage project repositories, documents, functionality, and results of enhancements and tests, track bugs and work with the CI/CD pipeline.
      source: Gitlab

      Jenkins has become a widely used tool in the DevOps environment. It has earned recognition for working with various plugins that allow flexible customization of CI/CD processes according to specific product development requirements.

      Docker is another highly efficient system for automatically deploying projects. It supports containerization and allows you to package a project, along with all environments and dependencies, into a container that can port them to a Linux system.

      Other popular environments for smooth CI/CD implementation:

      • Travis-CI. Users can connect this tool to GitHub repos with minimal configuration. The solution is cloud-based and does not require local installation. Plus, it's free for open-source projects.

      • Circle-CI. This product uses seamless integration with GitHub and provides a web interface for tracking build versions and maintaining tasks. Circle-CI connects its users by mail, Slack, and other communication channels.

      • PHP Censor. This is a continuous integration system server for automating PHP projects that allows teams to work with repos of GitLab, GitHub, Mercurial, etc. For testing, it uses the libraries Atom, PHP Spec, Behat, etc. The project has a lot of documentation in the stack, but users have to configure the tool themselves.

      • Rex. Rex is a great tool designed to automate the continuous integration process in data centers. It works in Perl scripts.

      • Open Build Service (OBS). This tool allows for the automation of CI/CD in the development of application distributions.

      Buildbot. This CI system allows you to automate the assembly and test apps. It supports modern VCS and provides for flexible build customization using Python components.

      CI/CD Pipeline Example

      Highly resilient container-based apps certainly have their advantages, but monitoring and ensuring their operation can be challenging. The good news is that Kubernetes is good at this. Plus, it is compatible with most CI/CD tools, allowing programmers to test, deploy, and update apps without downtime.

      Since Jenkins has become the most widely-used CI/CD tool, we will use it to show you how a pipeline works on Kubernetes.

      Implementing CI/CD Pipeline on Kubernetes by Jenkins

      Jenkins is a free program that allows you to organize the process of continuous integration and delivery of a software product. Jenkins pipeline will enable you to split up software delivery into stages, each of which can be controlled.
      source: AWS
      Once you install and customize Jenkins, the following window will appear:
      Go to the "Create First Admin User" page, insert all necessary credentials, and click "Save."
      Tap on Manage Jenkins.
      In the tab search field, tap "Available," select the plugins, and click "Install."

      Once you log in with the newly created account name, click "New Item", and choose "Freestyle project".
      The project configuration page will open, tap "Git" and then enter the GitHub repository URL.

      All that's left to do is choose several infrastructure parameters. For Build Triggers, pick the Poll SCM check box. Under Build Environment, select Delete workspace. Choose Deploy Revision and be ready to deploy.

      When finished, Jenkins will notify you of the successful deployment of your web application in the CI/CD pipeline.

      Business Benefits of CI/CD Implementation

      CI/CD tools empower organizations to deliver software updates to the user consistently. CI/CD allows companies to launch new functionality in a matter of days, while with the classic waterfall model, it might take several months. New services bring unique competitive business advantages and an opportunity to reproduce the functionality of competitors' solutions. You can even significantly outdo them in the development and implementation of new tools.

      Continuous integration and deployment tools give you the ability to detect the best product version through online testing and additional iterations. By discarding less promising solutions, you will save your company time and money.

      Thanks to the CI/CD pipeline, the quality of the result is higher: automated testing checks all aspects of the product, which is difficult to implement using a standard release approach. All bugs and errors are identified and fixed early in the development phase.

      Build, Test, Deploy with OpsWorks Co.

      As shown in the examples of Facebook, Etsy, and CSG show, releases and deployments should not necessarily have a high degree of tension nor require the dramatic efforts of dozens or hundreds of engineers. Instead, they can be as routine as any other part of daily work. In doing so, companies can reduce deployment time from a month to a few minutes, making it possible to quickly deliver value to customers without causing chaos or disruptions. In addition, by ensuring that the developers and the managers work together, companies can ultimately make the working conditions less stressful and intense.

      If you don't have the time to get into CI/CD implementation details on your own, then don't worry. With OpsWorks Co, you won't have to.

      To see if your infrastructure is ready for CI/CD integration, our team analyzes VCS flow (Git), release management, and the project technology stack to give you thorough DevOps strategy advice. We do our best to ensure that you achieve your business goals. To create an automation process that will benefit your specific system, we audit and analyze the specifics of development processes.

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