Hybrid CI/CD Orchestration: GitHub Actions, Jenkins & GitLab CI

Executive Summary

Multi-platform CI/CD occurs through acquisition, compliance mandates, and legacy system constraints. Orchestration requires 3-6 months implementation with 2-3 senior engineers. Budget $2-5k/month AWS costs plus platform licensing.

Configuration Requirements

Platform Assessment Matrix

Platform	Optimal Use Case	Critical Failure Mode	Monthly Cost	Learning Curve
GitHub Actions	Fast dev builds, simple CI	Custom runners crash with "Unable to connect to the server"	$50-500 (small teams), $0.008/minute scales rapidly	Easy start, nightmare at scale
Jenkins	Complex enterprise workflows, legacy systems	Plugin dependency hell, UI from 2005	$200-1000 compute, $5k+ enterprise licenses	Steep, then steeper
GitLab CI	Security scanning, compliance	Runners disappear during deployments	$99-999/user tier, runner costs extra	Better than Jenkins, worse than GitHub

Working Integration Patterns

Option 1: EventBridge + Lambda (AWS-centric)

• Cost reality: $500-2000/month depending on build volume
• Critical failure: Jenkins webhook spam can generate 250k events/day
• Breaking point: Lambda bill explosion from chatty webhooks
• Implementation time: 3-6 months

Option 2: Database Coordination

• Technology: Shared Postgres table tracking deployment state
• Critical requirement: Database locks to prevent race conditions
• Failure mode: Race conditions deploy half-finished builds to production

Option 3: Accept Chaos

• Strategy: Run platforms separately, coordinate manually for critical releases
• Advantage: May be superior to 6-month orchestration project that breaks with plugin updates

Shared Artifact Storage Configuration

S3 Pattern (Production-tested):

builds/${repo}/${commit_sha}/app.jar       # Jenkins artifacts
tests/${repo}/${commit_sha}/results.xml    # GitHub Actions test results
scans/${repo}/${commit_sha}/security.json  # GitLab security reports

Critical setting: Lifecycle policies delete after 30 days or storage bills become unmanageable

State Coordination Schema

DynamoDB table structure:

{
  "build_id": "repo-name-commit-sha",
  "github_status": "COMPLETED|RUNNING|PENDING|FAILED",
  "jenkins_status": "COMPLETED|RUNNING|PENDING|FAILED",
  "gitlab_status": "COMPLETED|RUNNING|PENDING|FAILED",
  "timestamp": "2025-09-17T10:30:00Z"
}

Critical Warnings

GitHub Actions Failure Modes

• Timeout issue: Default 6-hour timeout but runners die after 4 hours
• Fix: Add timeout-minutes: 360 to workflow jobs
• Self-hosted runners: Crash more frequently but provide control
• Architecture mismatch: CI runs Ubuntu 20.04, local development often macOS M1
• Debug command: uname -a && env | sort to identify environment differences

Jenkins Breaking Points

• Authentication change: Version 2.400+ requires API tokens, not passwords
• Workspace corruption: Multiple builds using same directory
• Required setting: deleteDir() before checkout in Jenkinsfile
• Disk space: Jenkins consumes 20GB per Docker build due to layer accumulation
• Webhook failure: Failed webhooks retry forever, requiring dead letter queues

GitLab CI Failure Scenarios

• Shared runner limits: 3-hour timeout with resource constraints
• Weekend failures: Runners disappear during off-hours deployments
• Solution: Self-hosted runner with gitlab-runner register
• Minimum instance: t3.large EC2 ($200/month) or builds crawl
• Registration attempts: Plan for 4 attempts to get token correct

EventBridge Cost Explosion

• Trigger: Jenkins webhook spam from misconfigured build triggers
• Impact: $2000/month bills from 50,000 webhook events
• Prevention: 5-second webhook timeout maximum
• Alternative: Simple HTTP endpoint with database

Resource Requirements

Timeline Reality

• Week 1-2: Basic webhook integration between two platforms
• Week 3-4: Add third platform, implement shared storage
• Week 5-8: State coordination, monitoring, debug Friday failures
• Month 2-3: Production deployment, security hardening
• Month 4-6: Cost optimization when AWS bill hits $5k/month

Human Resources

• Minimum requirement: 2-3 senior engineers for 6 months
• Critical expertise: Platform engineering, AWS services, security compliance
• Management expectation: "2-week sprint" estimates indicate lack of implementation experience

Financial Investment

• AWS costs: $2-5k/month for production setup
• GitHub Actions: $0.008/minute with self-hosted runners
• Jenkins enterprise: $50k/year starting point
• GitLab Ultimate: $999/user/year

Implementation Strategy

Working Deployment Flow

1. Dev builds: GitHub Actions only (fast feedback)
2. Staging: GitHub → Jenkins → GitLab pipeline (full security scanning)
3. Production: GitLab promotion after manual approval

Webhook Integration (Proven Pattern)

# GitHub Actions to Jenkins trigger
curl -X POST "https://jenkins.company.com/job/deploy/buildWithParameters" \
  --user "$JENKINS_USER:$JENKINS_TOKEN" \
  --data "artifact_path=s3://builds/${GITHUB_SHA}.tar.gz&commit=${GITHUB_SHA}"

Security Requirements

• Secrets management: AWS Systems Manager Parameter Store (cheaper than Secrets Manager)
• Network security: HTTPS everywhere, IP restrictions where possible
• Pre-commit hooks: Reject any commits containing secrets
• Never: Put secrets in Git, even temporarily

Rollback Strategy

• Keep: Last 3 deployments ready for immediate switch
• Lambda function: 30-second load balancer target swap vs 20-minute redeploy
• Blue/green: Each platform deploys to different slots

Monitoring and Troubleshooting

Basic Health Checks

#!/bin/bash
# Run every 5 minutes
curl -f https://api.github.com/status || echo "GitHub down"
curl -f "https://your-jenkins.company.com/api/json" || echo "Jenkins down"
curl -f "https://gitlab.example.com/api/v4/version" || echo "GitLab down"

Common Issues and Solutions

GitHub webhook stops triggering Jenkins:

• Cause: Signature validation change (late 2024)
• Rate limiting: 10-second response timeout or exponential backoff up to 24 hours
• Test: curl -X POST your-jenkins-url/github-webhook/ -H "X-GitHub-Event: push" -d '{}'

Docker image sharing:

• Pattern: registry.company.com/app:${COMMIT_SHA}
• Strategy: Build once in GitHub Actions, deploy everywhere else
• Avoid: Rebuilding same code three times

GitLab security scanning blocks deployment:

• Override: Add exceptions to .gitlab-ci.yml
• Strategy: Ignore low/medium severity if security team approves

Decision Criteria

When to Build Hybrid CI/CD

• Migration cost exceeds integration cost: 500+ Jenkins jobs with 50+ GitHub-trained developers
• Compliance requirements: Security team mandates specific scanning tools
• Acquisition scenarios: Inherited different platforms through company purchases

When to Avoid

• Simple requirements: Single platform can meet all needs
• Small teams: Maintenance overhead exceeds benefits
• Greenfield projects: No legacy constraints requiring multiple platforms

Success Metrics

• Circuit breaker functionality: Graceful degradation when one platform fails
• Complete pipeline paths: Emergency deployment capability on each platform
• Cost optimization: AWS bills under control within 6 months
• Reliability: Deployments succeed without Friday afternoon failures

Critical Success Factors

1. Don't optimize for perfection: Make it work, then reliable, then fast
2. Expect platform updates to break integration: Plan for ongoing maintenance
3. Monitor costs aggressively: EventBridge and runner costs escalate rapidly
4. Implement circuit breakers: Platform failures shouldn't stop all deployments
5. Document tribal knowledge: Bob's retirement shouldn't break the system