CI/CD Pipeline for Versioned Docker Releases Using GitLab

To make deployments easier and more reliable, I have created a GitLab CI/CD pipeline.

Whenever I push code to a release-X.X.X branch, GitLab automatically builds a Docker image with the updated index.html, tags the repository, and pushes the image to DockerHub. A manual deployment job is also available, giving me full control over when to release the image.

Figure: GitLab CI/CD flow for versioned Docker releases

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Prerequisites

To set this up, I already had:

• An EC2 instance with Docker installed and accessible via SSH
• A GitLab repository for storing the .gitlab-ci.yml file
• A DockerHub account with credentials ready

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Pipeline Configuration

.gitlab-ci.yml

stages:
  - build
  - tag
  - deploy

variables:
  DOCKER_IMAGE: vamsi193/release-cicd

workflow:
  rules:
    - if: '$CI_COMMIT_REF_NAME =~ /^release-\d+\.\d+\.\d+$/'
      when: always
    - when: never

build_image:
  stage: build
  tags:
    - my-runner
  script:
    - echo "$DOCKERHUB_PASSWORD" | docker login -u "$DOCKERHUB_USERNAME" --password-stdin
    - TAG_NAME="${CI_COMMIT_REF_NAME#release-}"
    - echo "TAG_NAME=$TAG_NAME" > tag.env
    - docker build -t $DOCKER_IMAGE:$TAG_NAME .
    - docker push $DOCKER_IMAGE:$TAG_NAME
  artifacts:
    reports:
      dotenv: tag.env

tag_repo:
  stage: tag
  tags:
    - my-runner
  dependencies:
    - build_image
  script:
    - git tag v$TAG_NAME
    - git push https://oauth2:${CI_GITLAB_PAT}@gitlab.com/vamsi193/release-cicd.git v$TAG_NAME

manual_deploy:
  stage: deploy
  tags:
    - my-runner
  script:
    - echo "Stopping existing container if it exists..."
    - docker stop release-app || true
    - docker rm release-app || true
    - docker run -d --name release-app -p 80:80 $DOCKER_IMAGE:$TAG_NAME
  when: manual

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Workflow Logic

The workflow block ensures the pipeline runs only when the branch name follows the release-X.X.X format:

workflow:
  rules:
    - if: '$CI_COMMIT_REF_NAME =~ /^release-\d+\.\d+\.\d+$/'
      when: always
    - when: never

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Stage Breakdown

• build_image: Builds the Docker image, tags it with the version, and pushes it to DockerHub.
• tag_repo: Automatically tags the Git repository with vX.X.X.
• manual_deploy: Lets me deploy the container manually when I’m ready — no automatic production deploys.

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GitLab Pipeline Status

DockerHub images with tag

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Insights from this Pipeline

• Built and pushed Docker images when a release tag is created DockerHub

• Tagged the Git repository with the version GitLab Repository

• Deployed the image manually in a safe and controlled way Pipeline View

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