Continuous Integration, Delivery and Deployment: A Systematic Review on Approaches, Tools, Challenges and Practices

Context: Continuous practices, i.e., continuous integration, delivery, and deployment, are the software development industry practices that enable organizations to frequently and reliably release new features and products. With the increasing interest in and literature on continuous practices, it is important to systematically review and synthesize the approaches, tools, challenges, and practices reported for adopting and implementing continuous practices. Objective: This research aimed at systematically reviewing the state of the art of continuous practices to classify approaches and tools, identify challenges and practices in this regard, and identify the gaps for future research. Method: We used systematic literature review (SLR) method for reviewing the peer-reviewed papers on continuous practices published between 2004 and 1st June 2016. We applied thematic analysis method for analysing the data extracted from reviewing 69 papers selected using predefined criteria. Results: We have identified thirty approaches and associated tools, which facilitate the implementation of continuous practices in the following ways: (1) “reducing build and test time in continuous integration (CI)”; (2) “increasing visibility and awareness on build and test results in CI”; (3) “supporting (semi-) automated continuous testing”; (4) “detecting violations, flaws and faults in CI”; (5) “addressing security and scalability issues in deployment pipeline”, and (6) “improving dependability and reliability of deployment process”. We have also determined a list of critical factors such as “testing (effort and time)”, “team awareness and transparency”, “good design principles”, “customer”, “highly skilled and motivated team”, “application domain”, and “appropriate infrastructure” that should be carefully considered when introducing continuous practices in a given organization.

💡 Research Summary

This paper presents a systematic review of the state‑of‑the‑art research on continuous integration (CI), continuous delivery (CD), and continuous deployment (CD) – collectively referred to as continuous practices – with the goal of classifying the approaches and tools that support them, identifying the challenges practitioners face, and extracting practical recommendations for successful adoption. The authors followed the systematic literature review (SLR) methodology, searching for peer‑reviewed articles published between 2004 and 1 June 2016. After applying predefined inclusion and exclusion criteria, 69 primary studies were selected for in‑depth analysis.

Data extraction captured each study’s objectives, proposed techniques, tools used, experimental settings, results, and reported limitations. The authors then performed a thematic analysis on the extracted data, which yielded six high‑level themes that capture the core functional objectives of continuous practices: (1) reducing build and test time in CI, (2) increasing visibility and awareness of CI results, (3) supporting (semi‑)automated continuous testing, (4) detecting violations, flaws, and faults early in the pipeline, (5) addressing security and scalability concerns in the deployment pipeline, and (6) improving the dependability and reliability of the deployment process.

Within these themes, the review identified thirty distinct approaches and the associated tooling ecosystems. For example, to shorten build and test cycles, researchers propose parallel builds, incremental compilation, caching mechanisms, and test selection strategies; these are typically realized with CI servers such as Jenkins, Travis CI, Bamboo, and build tools like Maven, Gradle, or Bazel. To improve visibility, dashboards (SonarQube, Grafana), real‑time notifications (Slack, HipChat), and log aggregation platforms (ELK stack) are highlighted. Automated testing support is achieved through container‑based isolation, service virtualization, and test‑generation frameworks such as Selenium, Cucumber, and TestNG, often orchestrated with Docker. Early defect detection relies on static analysis tools (FindBugs, PMD, Checkstyle) and quality‑gate enforcement in CI pipelines. Security and scalability are addressed by secret management solutions (HashiCorp Vault), container orchestration platforms (Kubernetes, Docker Swarm), and service‑mesh technologies (Istio). Finally, reliability of deployment is enhanced through blue‑green and canary release strategies, automated rollback mechanisms, and GitOps‑style pipelines using tools like Spinnaker, Argo CD, and Terraform.

Beyond technical solutions, the authors distilled a set of critical success factors that must be considered when introducing continuous practices in an organization. These factors include: (a) testing effort and time – the need to balance thoroughness with speed; (b) team awareness and transparency – fostering a culture where build and deployment status is openly shared; (c) good design principles – modularity, separation of concerns, and reusability to keep pipelines maintainable; (d) customer involvement – frequent feedback loops that justify rapid releases; (e) highly skilled and motivated teams – expertise in DevOps tooling and a willingness to experiment; (f) application domain – constraints specific to embedded, real‑time, or safety‑critical systems; and (g) appropriate infrastructure – sufficient compute, networking, and storage resources, whether on‑premise or in the cloud.

The review also points out gaps in the existing literature. First, there is a lack of longitudinal studies that quantify maintenance costs and technical debt introduced by continuous pipelines over time. Second, security testing and policy‑based deployment verification are still under‑represented, despite the growing sophistication of attacks on CI/CD environments. Third, most empirical evidence comes from large open‑source projects or well‑funded enterprises, leaving the applicability to small‑ and medium‑size enterprises (SMEs) and specialized domains such as medical, automotive, or financial software insufficiently explored. Fourth, interoperability among tools and the need for standardized interfaces remain open challenges.

In conclusion, the paper offers a comprehensive taxonomy of approaches and tools, a clear articulation of the challenges, and a set of actionable recommendations for practitioners. By highlighting both the technical and socio‑organizational dimensions of continuous practices, it provides a valuable roadmap for researchers seeking to fill the identified gaps and for industry professionals aiming to mature their CI/CD pipelines in a systematic, reliable, and secure manner.