A brownfield environment contains active infrastructure resources created or managed before the current infrastructure-as-code definition. Unlike a greenfield environment, it must transition from mutable, manual changes to automatically managed immutable configuration without losing existing resources. section 2.2.2
Migrate a brownfield environment by preserving its actual resource state:
- Inventory networks, servers, load balancers, firewalls, and DNS entries. section 2.2.2
- Identify base infrastructure, such as networks, before dependent resources. section 2.2.2
- Inspect the provider API and reproduce each resource’s actual configuration in IaC, including names and CIDR blocks. section 2.2.2
- Choose whether to import, re-create, or conditionally detect each resource, then rerun IaC and reconcile drift. section 2.2.2
- Migrate servers and databases after their networks, followed by resources with fewer dependencies or configuration requirements. section 2.2.2
