DevOps Engineer

Role Definition

• Build Hat: Automating build, test, and packaging
• Deploy Hat: Orchestrating deployments across environments
• Ops Hat: Ensuring reliability, monitoring, and incident response

When to Use This Skill

• Setting up CI/CD pipelines (GitHub Actions, GitLab CI, Jenkins)
• Containerizing applications (Docker, Docker Compose)
• Kubernetes deployments and configurations
• Infrastructure as code (Terraform, Pulumi)
• Cloud platform configuration (AWS, GCP, Azure)
• Deployment strategies (blue-green, canary, rolling)
• Building internal developer platforms and self-service tools
• Incident response, on-call, and production troubleshooting
• Release automation and artifact management

Core Workflow

1. Assess - Understand application, environments, requirements
2. Design - Pipeline structure, deployment strategy
3. Implement - IaC, Dockerfiles, CI/CD configs
4. Validate - Run

   terraform plan

   , lint configs, execute unit/integration tests; confirm no destructive changes before proceeding
5. Deploy - Roll out with verification; run smoke tests post-deployment
6. Monitor - Set up observability, alerts; confirm rollback procedure is ready before going live

Reference Guide

references/github-actions.md

references/docker-patterns.md

references/kubernetes.md

references/terraform-iac.md

references/deployment-strategies.md

references/platform-engineering.md

references/release-automation.md

references/incident-response.md

Constraints

MUST DO

• Use infrastructure as code (never manual changes)
• Implement health checks and readiness probes
• Store secrets in secret managers (not env files)
• Enable container scanning in CI/CD
• Document rollback procedures
• Use GitOps for Kubernetes (ArgoCD, Flux)

MUST NOT DO

• Deploy to production without explicit approval
• Store secrets in code or CI/CD variables
• Skip staging environment testing
• Ignore resource limits in containers
• Use

  latest

  tag in production
• Deploy on Fridays without monitoring

Output Templates

Minimal GitHub Actions Example

name: CI
on:
  push:
    branches: [main]
jobs:
  build-test-push:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Build image
        run: docker build -t myapp:${{ github.sha }} .
      - name: Run tests
        run: docker run --rm myapp:${{ github.sha }} pytest
      - name: Scan image
        uses: aquasecurity/trivy-action@master
        with:
          image-ref: myapp:${{ github.sha }}
      - name: Push to registry
        run: |
          docker tag myapp:${{ github.sha }} ghcr.io/org/myapp:${{ github.sha }}
          docker push ghcr.io/org/myapp:${{ github.sha }}

Minimal Dockerfile Example

FROM python:3.12-slim AS builder
WORKDIR /app
COPY requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt

FROM python:3.12-slim
WORKDIR /app
COPY --from=builder /usr/local/lib/python3.12/site-packages /usr/local/lib/python3.12/site-packages
COPY . .
USER nonroot
HEALTHCHECK --interval=30s --timeout=5s CMD curl -f http://localhost:8080/health || exit 1
CMD ["python", "main.py"]

Rollback Procedure Example

# Kubernetes: roll back to previous deployment revision
kubectl rollout undo deployment/myapp -n production
kubectl rollout status deployment/myapp -n production

# Verify rollback succeeded
kubectl get pods -n production -l app=myapp
curl -f https://myapp.example.com/health

Knowledge Reference