1. Overview (Project Background)

DoAllTech is a B2B SaaS company supporting digital transformation in the construction industry,
providing various solutions including project management, access control, and drawing management.

With increasing customer numbers and SaaS business expansion, the existing Windows-based EC2-centric legacy architecture reached its limits
in terms of service scalability, deployment speed, and cost efficiency.

Accordingly, DoAllTech pursued a project aimed at not just a simple infrastructure migration,
but rather a transition to a container-based SaaS architecture and service modernization (App Modernization)
to simultaneously secure business agility, multi-tenancy security, and operational efficiency.

2. Challenge (Problem Definition)

Prior to the project, DoAllTech faced the following business and technical challenges.

Business Perspective

• Slow service reflection speed requiring several days to reflect customer requirements and improve features

• Concerns about service stability degradation due to traffic surges when user numbers increase

• Need to secure multi-tenancy structure and revenue scalability for SaaS model transition

Technical Perspective

• Limitations in scaling and deployment due to monolithic .NET application structure

• Operational complexity due to lack of IaC and automation

• Absence of modern architecture suitable for organic service integration and expansion

• Need for security, authentication, and isolation models in multi-tenant environments

These limitations became factors hindering continuous growth and SaaS business expansion.

3. Solution (Resolution Approach)

DoAllTech, together with MegazoneCloud, established a phased SaaS transition strategy,
and restructured services centered on AWS-based container architecture and DevOps automation.

1. Architecture Diagnosis and Redesign

• Architecture design considering reliability, scalability, and cost efficiency through AWS Well-Architected Review (WAR)

• Restructuring existing EC2-based services from an App Modernization perspective

2. Container-Based Service Transition

• Transitioning existing Windows/.NET workloads to Linux container-based ECS architecture

• Separating monolithic structure into function-specific microservices

• Implementing multi-tenant authentication and tenant isolation model based on AWS Cognito

3. CI/CD and IaC Enhancement

• GitHub Actions + AWS CodePipeline/CodeDeploy integration

• Applying ECS-based Blue-Green zero-downtime deployment

• Codifying ECS, ECR, ALB, and CI/CD resources through Terraform-based IaC

4. Cost Optimization Operations Strategy

• Reducing operational complexity and labor costs by choosing ECS over EKS

• Optimizing container density using M7i-flex and ENI Trunking

• Continuous cost reduction through flexible staging environment operations and build cache strategy

Through this, we secured both operational stability and service innovation speed.

4. Result (Achievements)

Through SaaS transition and infrastructure modernization, DoAllTech achieved the following results.

• Improved service response speed and customer satisfaction

• 60% reduction in service deployment cycle
  (Manual deployment → Automatic deployment within 5 minutes after Git push)

• Reduced infrastructure operations burden on development team to secure product innovation-focused environment

• Secured scalable SaaS architecture based on multi-tenancy

• Established foundation for future growth through cost-effective and stable operations structure

Based on this, DoAllTech is actively expanding its B2B SaaS business.