From IaC to AI: Adopting OpenTofu and ChatOps

As service scale grew, the LINE Plus SRE team adopted IaC (Infrastructure as Code) to solve the increasing complexity of infrastructure management. Previously, each team managed infrastructure differently using dashboards, scripts, wikis, and other methods, making it difficult to track change history and increasing operational burden.

To address this, the team adopted a GitOps workflow. By declaring the Desired State of infrastructure in Git and managing all changes through Pull Requests (PRs) and CI/CD pipelines, they began managing infrastructure as an engineering artifact at the same level as application code.

For tooling, the team chose OpenTofu and Terragrunt. OpenTofu is an open-source fork of Terraform that maintains compatibility with existing HCL syntax and Providers while offering an open-source license, which lowers the learning curve and allows reuse of existing modules.

Currently, about 1,500 resources are managed as code, and infrastructure changes across 7 services are all applied through PR reviews. The team has also established a system that automatically detects discrepancies between code and actual infrastructure every day and sends alerts.