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CD Model Overview

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Introduction

The Continuous Delivery (CD) Model provides a comprehensive framework for delivering software from initial development through production deployment and ongoing maintenance.

The model ensures quality, traceability, and compliance throughout the entire software delivery lifecycle.

Unlike traditional linear Software Development Lifecycle (SDLC) approaches that rely on manual handoffs and stage-gate approvals, the CD Model integrates automation, quality gates, and continuous validation at every step.

This approach reduces lead time, increases deployment frequency, and improves software quality through rapid feedback loops.

The 12-Stage Model

The CD Model consists of 12 distinct stages that guide software from code authoring to production operation:

CD Model Full View

This visualization shows the complete flow through all stages, including quality gates, environment transitions, and approval points.

Mermaid diagram

Development Stages (1-7):

  1. Authoring - Create code, config, requirements on local topic branches
  2. Pre-commit - Verify changes before committing (5-10 min time-box)
  3. Merge Request - Peer review and automated verification
  4. Commit - Integrate verified changes into main branch
  5. Acceptance Testing - Validate functional requirements in PLTE
  6. Extended Testing - Performance, security, and compliance validation
  7. Exploration - Stakeholder validation and exploratory testing

Release Stages (8-12):

  1. Start Release - Create release candidate and documentation
  2. Release Approval - Obtain formal approval for production deployment
  3. Production Deployment - Deploy to production environment
  4. Live - Monitor and validate production behavior
  5. Release Toggling - Control feature exposure with feature flags

For detailed stage explanations, see The 12 Stages.

Traditional vs CD Model

Traditional SDLC (Waterfall/Stage-Gate):

  • Development → Testing → Validation → Production
  • Manual handoffs between teams/silos
  • Testing happens late in the cycle
  • Long feedback loops (weeks to months)
  • Environment-specific configurations that drift
  • Bottlenecks when multiple teams share environments

CD Model Approach:

  • Purpose-built stages for specific validation activities
  • Automated progression based on quality gates
  • Testing integrated throughout the pipeline
  • Rapid feedback loops (seconds to minutes to hours)
  • Infrastructure as Code ensures consistency
  • Parallel execution without environment conflicts

Benefits

Faster Time to Market:

  • Automated pipeline reduces manual delays
  • Parallel testing accelerates validation
  • Continuous integration prevents integration debt

Higher Quality:

  • Early defect detection through shift-left practices
  • Automated testing at every stage
  • Quality gates prevent defects from progressing

Reduced Risk:

  • Small, frequent changes are easier to validate and rollback
  • Automated compliance checks ensure consistency
  • Production-like testing catches issues before deployment

Better Compliance:

  • Automated evidence generation
  • Traceability from requirements to deployment
  • Audit trail built into the pipeline

Improved Developer Experience:

  • Fast feedback loops (minutes, not days)
  • Clear quality expectations
  • Automated repetitive tasks

How to Use This Documentation

If you're new to the CD Model:

  1. Read this overview to understand the concept
  2. Review The 12 Stages to understand the complete flow
  3. Explore Variants to choose your configuration

If you're implementing the CD Model:

  1. Choose your variant (RA or CDe) using Variants
  2. Review Environments for infrastructure needs
  3. Review Testing Strategy for test coverage
  4. Review Compliance for evidence requirements

If you're reading CD Model diagrams:

References

Tutorials | How-to Guides | Explanation | Reference

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