The Journey of Moving Away from Legacy Infrastructure to Build a Hybrid Cloud

Toss Payments faced serious legacy infrastructure issues after acquiring a PG business that had been operating for over 20 years. In particular, because network routing was handled directly by servers rather than network equipment, some servers contained as many as 1,997 routing entries, making the system unmanageable.

Initially, they used public cloud services such as AWS to run new services, but ran into limitations including rising costs, exchange rate fluctuations, and a lack of control and DR (Disaster Recovery) configuration with the on-premises environment.

To address this, they built an OpenStack-based private cloud and set the ultimate goal of running it as a hybrid cloud, operating in Active-Active mode alongside the public cloud.

The private cloud was designed to meet three key requirements:

• Agile infrastructure: to support fast product development speed
• Flexibility: to handle diverse requirements such as VMs, containers, and Kubernetes
• Open source foundation: adopting OpenStack for technology internalization and cost savings

Despite a shortage of operations personnel, the team's dedication enabled them to build a production-level operating environment.