Skip to main content
PROJECT / CLOUD·PRODUCTION CASE STUDY·Cloud / DevOps Engineer

Enterprise Cloud Modernization

Auditing & Migrating 40+ Workloads across 400+ Resource Groups

Architected and executed an infrastructure & DevOps modernization for a leading private aviation company. Migrated 40+ workloads into a Cloud Adoption Framework (CAF) compliant hub-and-spoke architecture.

40+ Workloads · 400+ Resource Groups · 40+ Subscriptions
#Azure#Terraform#Hub-and-Spoke#ExpressRoute#Azure Firewall#APIM#Private Endpoints#Managed Identity
// SYSTEM ARCHITECTURE & TOPOLOGY
01 / THE PROBLEM

The Challenge & Context

The client operated an unmanaged, sprawling Azure footprint spanning over 40 subscriptions and 400+ resource groups with no unified networking model, unsegmented production/non-production environments, manual click-ops provisioning, and severe network latency between on-premises aviation dispatch systems and cloud services.

02 / THE SOLUTION

Engineering Approach

Engineered a greenfield, Cloud Adoption Framework (CAF) aligned hub-and-spoke landing zone. Codified the entire network and security foundation in modular Terraform, established dedicated ExpressRoute and VPN Gateway connectivity to on-prem datacenters, enforced zero-trust Private Endpoints across all PaaS data services, and automated CI/CD deployment pipelines.

03 / ARCHITECTURE

Components & Data Flow

A central connectivity hub subscription hosts redundant Azure Firewall instances, Application Gateway with WAF, and ExpressRoute gateways. Spokes host isolated workload tiers (Production, Staging, Shared Services) connected via VNet Peering with forced tunneling through the hub firewall. All data stores (Azure SQL, Storage, Key Vault) communicate strictly over Private Endpoints with public access disabled.

04 / ENGINEERING DECISIONS

Key Trade-offs & Decisions

DECISION_01

Modular Terraform over Monolithic State

Divided the 400+ resource groups into isolated Terraform workspaces with remote state data sources to prevent state locking bottlenecks and contain blast radius.

DECISION_02

Private Endpoints over Service Endpoints

Private Endpoints provide dedicated private IP addresses within VNets, eliminating public IP exposure and enabling granular NSG controls.

DECISION_03

Managed Identities (UAMI) over Service Principals

Eliminated hardcoded credentials and secret rotation overhead across all containerized workloads and CI/CD runners.

05 / IMPLEMENTATION CHALLENGES

Obstacles & How They Were Overcome

CHALLENGE: Zero-Downtime Migration of Aviation Dispatch Workloads

RESOLUTION:Implemented parallel routing with DNS-based cutovers and automated health check validation, ensuring critical flight tracking services experienced zero interrupted transactions.

CHALLENGE: State Reconciliation across 40+ Subscriptions

RESOLUTION:Built custom automated discovery scripts to inventory and tag unmanaged resources prior to importing into version-controlled Terraform state.

06 / OUTCOME

Measurable Impact

100% of network traffic routed through centralized, audited Azure Firewall inspection.
Zero security findings during external compliance audit across 400+ resource groups.
Deployment provisioning time dropped from days to minutes through codified Terraform pipelines.
07 / WHAT I LEARNED

Field Lessons & Takeaways

Automate governance policies before migrating workloads; retrofitting tagging and NSG rules on live workloads is 5x more time-consuming.
Network latency on ExpressRoute must be actively monitored with Network Watcher connection monitors rather than relying on portal metrics alone.