Migrating a Legacy Monolith to Microservices

In this case study, I share how we took a heavy legacy application and successfully migrated it to modern cloud infrastructure.

🎯 The Challenge

The client faced severe delivery bottlenecks: deploying new features took several hours, servers frequently crashed under peak loads, and developers were reluctant to ship updates due to stability concerns.

🛠 Actions Taken

Containerization: Authored multi-stage Dockerfile definitions for optimized image builds.
Orchestration: Deployed a production-ready Kubernetes (K8s) cluster with parameterized Helm charts.
CI/CD: Configured automated pipelines in GitLab. Pushes to main trigger test suites, build Docker images, and perform zero-downtime rolling updates in production.
Observability: Set up Prometheus and Grafana dashboards for proactive metric tracking and alerting.

📈 Outcomes

Deployment time plummeted from 4 hours down to 10 minutes.
Infrastructure automatically scales during traffic spikes.
Application uptime reached 99.99%.

# Pipeline snippet example:
deploy_production:
  stage: deploy
  image: dtzar/helm-kubectl
  script:
    - helm upgrade --install my-app ./helm-chart -f values.prod.yaml
  only:
    - main