Automating Docker Image Build and Deployment Using GitLab CI/CD

Abstract: The exponential growth of cloud-native applications and microservices architectures demands robust, scalable, and automated deployment mechanisms. This paper presents a comprehensive CI/CD-based automated pipeline system for Docker image building and application deployment using GitLab pipelines. The proposed system integrates containerization using Docker with automated workflows defined in GitLab's YAML-based configuration system. By eliminating manual intervention in the build, test, and deployment lifecycle, the system significantly reduces human error, ensures consistency in runtime environments, and accelerates software delivery velocity. Key aspects include Dockerfile authoring strategies, GitLab Runner configuration, registry management, and environment-specific deployment triggers. Experimental results demonstrate that pipeline execution time, deployment reliability, and developer productivity are substantially improved compared to conventional manual deployments. This work contributes a replicable architecture that aligns with modern DevOps practices, supporting continuous integration, continuous delivery, and infrastructure-as- code paradigms.

Keywords: Docker, GitLab CI/CD, DevOps, Containerization, Automated Deployment, Microservices, Infrastructure as Code, GitLab Runner, Continuous Integration, Continuous Delivery