1. Overview (Project Background)

C Company reviewed the continuation of existing IDC infrastructure operations as it became outdated. The company determined that simple maintenance alone would not be sufficient to adequately address future service stability, security, and operational risks. Rather than continuing to operate legacy systems, the company decided to pursue AWS migration through replatforming to eliminate risks from end-of-support (EOS) services and resources while securing operational efficiency and scalability.

2. Challenge (Problem Definition)

C Company faced the following key challenges in its pre-cloud migration operating environment.

• Active Directory Permission Issues: The existing Active Directory had separate policies applied per user, including dealer employees, resulting in inconsistent policy application. The authority definition, approval, and change management system by job category was inadequate, making authority ownership and change history unclear. This caused difficulties in pre-migration authority assessment, schedule delays, and security risks.

• Outdated Operating System Environment: Multiple end-of-support (EOS) operating system versions from Windows 2008 to 2016 were mixed together, and no operational standards or version management policies were in place. This resulted in difficulties in applying security patches, validating compatibility, and ensuring consistency in operations and support, leading to increased system instability and maintenance costs.

• Collaboration and Work Constraints Due to Time Difference: The migration work was performed by MegazoneCloud (external vendor) while the service operations team was handled by the local H Company UK organization. Due to the time difference between Korea and the UK, real-time decision-making and collaboration were not smooth. This frequently resulted in delayed response to issues, communication errors, and inefficient work coordination.

3. Solution (Resolution Approach)
 

MegazoneCloud executed the cloud migration centered on a global collaboration system and infrastructure modernization strategy.

• Assessment: Previously, due to the complex permission structure, certain permissions required for assessment were lacking without Administrator privileges. We identified and collected missing permissions, redesigned the permission structure, and reorganized permissions to fit the project execution, thereby securing necessary operational permissions safely.

• Replatform and AWS-based AD Construction: All legacy resources were upgraded to Windows Server 2019 or higher versions. We collaborated with local personnel to repeatedly conduct service-specific testing to ensure no issues at the time of launch. Additionally, we configured domain controllers on AWS to secure the stability of authentication and directory services during the AD migration process.

• Simultaneous On-site and Remote Support System: To facilitate smooth communication and rapid problem resolution, we dispatched on-site personnel to the UK and arranged working hours so that Korean support staff overlapped by at least 4 hours or more. Work performed in Korea was recorded and shared through detailed work logs, enabling the UK local team to quickly understand the situation and adapt to subsequent tasks.

4. Result (Achievements)

Through successful cloud migration and operational system improvements, we achieved the following business results.

• Establishment of Stable Cloud Operations Governance

  • Provided operational manuals, procedures, and incident response scenarios.

  • Conducted hands-on training (operations and recovery workshops) and applied onboarding checklists.

  • Clearly defined operational SLAs and responsibility allocation (RACI).

• Active Directory Policy Redesign

  • Conducted comprehensive investigation of existing permission structures and GPOs and performed permission mapping.

  • Implemented least privilege principle-based permission redistribution and standardized templates.

  • Established change approval and validation processes (including test and rollback scenarios).

• Zero EOS Resource Risk

  • Consolidated and upgraded Windows Server and core applications to supported versions.

  • Enhanced security patching, vulnerability assessment, and network access controls.

  • Completed all functionality, compatibility, and performance validation after upgrade.