> ## Documentation Index > Fetch the complete documentation index at: https://notes.kodekloud.com/llms.txt > Use this file to discover all available pages before exploring further. # Basics of CICD > This article explains the key concepts of Continuous Integration and Continuous Delivery/Deployment, emphasizing their importance in modern software engineering. In this lesson, we’ll cover the key concepts of Continuous Integration (CI) and Continuous Delivery/Deployment (CD), explore a typical Git-based workflow, and highlight why CI/CD is vital for modern software engineering. *** ## 1. A Typical Git Workflow All source code is maintained in a Git repository, usually hosted on platforms like GitLab, GitHub, or Bitbucket. Collaboration features—such as Merge Requests (MRs), pipelines, and permission controls—streamline team workflows. 1. Developers branch off the protected **main** branch to create isolated **feature branches**. 2. They commit and push changes to their feature branch. 3. An MR is opened to merge the feature into **main**, triggering code review. 4. After approvals, changes merge into **main** and deploy to the target environment. Enable branch protection on **main** to require MRs and automated checks before merging. Without CI/CD automation, manual testing and deployments introduce risks: | Risk | Impact | | --------------------- | -------------------------------------------- | | No guaranteed testing | Bugs slip into production | | Manual errors | Misconfigurations, inconsistent environments | | Slow feedback loops | Delayed fixes and longer release cycles | ![The image is a diagram explaining the CI/CD process, showing the flow from feature branch creation to deployment and production, including steps like commit, pull request, review, and approval.](https://kodekloud.com/kk-media/image/upload/v1752877294/notes-assets/images/GitLab-CICD-Architecting-Deploying-and-Optimizing-Pipelines-Basics-of-CICD/ci-cd-process-diagram-flow.jpg) *** ## 2. Challenges of Manual Integration When multiple developers merge without CI pipelines, teams often face: | Challenge | Description | | ------------------- | ---------------------------------------------------------------------- | | Delayed Testing | QA happens post-merge, making bug isolation and fixes more difficult. | | Inefficient Deploys | Manual steps across dev, staging, and production increase error rates. | | QA Bottlenecks | Manual quality checks slow down releases and risk missing regressions. | ![The image illustrates a workflow for continuous integration, highlighting the process from feature branches to production, and emphasizes the challenges of delayed testing, inefficient deployment, and quality assurance without CI.](https://kodekloud.com/kk-media/image/upload/v1752877295/notes-assets/images/GitLab-CICD-Architecting-Deploying-and-Optimizing-Pipelines-Basics-of-CICD/ci-workflow-feature-branches-production.jpg) *** ## 3. Introducing Continuous Integration Continuous Integration ensures that every code change is automatically tested and validated before merging into **main**. 1. Developer 1 branches off **main** to work on **feature-A**. 2. Opening an MR triggers the CI pipeline, which performs: * Unit tests * Dependency and license scans * Artifact builds * Static code analysis and vulnerability scanning 3. If any stage fails, the MR remains open for fixes; pushing new commits retriggers CI. 4. On passing all checks, the MR is approved and merged into **main**. 5. A post-merge pipeline runs integration tests against the updated **main** branch. Meanwhile, Developer 2 works on **feature-B** in parallel. Once feature-B’s MR passes CI and merges, the post-merge pipeline verifies that A and B integrate without conflict, keeping **main** stable and healthy. Fast feedback from CI pipelines helps catch issues early and reduces merge conflicts. ![The image illustrates a continuous integration workflow, showing steps from feature branching and committing to production, including unit testing, dependency scanning, building artifacts, and code scanning.](https://kodekloud.com/kk-media/image/upload/v1752877296/notes-assets/images/GitLab-CICD-Architecting-Deploying-and-Optimizing-Pipelines-Basics-of-CICD/continuous-integration-workflow-diagram.jpg) *** ## 4. From Integration to Delivery and Deployment Once CI validates code quality, CD automates the path to production: | Process | Deployment Target | Human Gate Required | Typical Use Case | | --------------------- | ------------------------------ | ------------------- | --------------------------- | | Continuous Delivery | Non-production (e.g., staging) | Yes | Manual approval before prod | | Continuous Deployment | Production | No | Fully automated releases | 1. **Continuous Delivery** * Deploys to staging or QA environments. * Executes integration, performance, and end-to-end tests. * Awaits manual approval for production. 2. **Continuous Deployment** * Automatically deploys to production after successful CI. * Ideal for teams with mature test suites and low risk tolerance. Skipping manual approvals in CD demands comprehensive automated tests to prevent production incidents. ![The image illustrates a continuous deployment/delivery pipeline, showing the process from feature branch creation to production deployment, including stages like commit, pull request, review, CI/CD, and testing. It includes elements like unit testing, dependency scanning, and code scanning, with paths for both continuous deployment and delivery.](https://kodekloud.com/kk-media/image/upload/v1752877298/notes-assets/images/GitLab-CICD-Architecting-Deploying-and-Optimizing-Pipelines-Basics-of-CICD/continuous-deployment-pipeline-diagram.jpg) *** ## Summary * **Continuous Integration (CI)** automates testing and validation for every code change. * **Continuous Delivery (CD)** adds automated deployments to staging with a human gate. * **Continuous Deployment** fully automates production releases. Together, CI/CD accelerates release cycles, ensures higher software quality, and minimizes operational risks. *** ## Links and References * [GitLab CI/CD Documentation](https://docs.gitlab.com/ee/ci/) * [Continuous Integration on Wikipedia](https://en.wikipedia.org/wiki/Continuous_integration) * [DevOps Practices](https://en.wikipedia.org/wiki/DevOps)