Disaster Recovery with IaC — Rebuild Your Entire Infrastructure from Code

Traditional disaster recovery relies on running duplicate infrastructure in a standby region — expensive and complex to maintain. IaC changes the equation. If your entire infrastructure is defined in Terraform, recreating it in a new region is a terraform apply with different variables. You do not need to maintain a hot standby; you need to maintain your code and your data backups.

This is the pilot light or warm standby approach to DR. The infrastructure code is always ready. Data is replicated to the DR region via cross-region replication (S3, RDS, DynamoDB). When a disaster occurs, you apply the Terraform code against the DR region, point DNS to the new infrastructure, and restore data from backups. Recovery time depends on resource provisioning speed and data volume, but it is measured in minutes to hours rather than days.

The key requirement is that your Terraform code must be region-agnostic. Hardcoded AMI IDs, AZ names, and region-specific resources break this. We parameterize everything so the same code works in us-east-1 and eu-west-1 by changing a single variable.

Data Replication: We configure cross-region replication for all stateful services. S3 buckets replicate to the DR region with the same lifecycle policies. RDS uses cross-region read replicas that can be promoted to primary. DynamoDB global tables provide active-active replication. Terraform manages all replication configuration as code.

Infrastructure Code: We parameterize your Terraform modules for multi-region deployment. Region, AZ count, AMI mappings, and VPC CIDR blocks are all variables. A DR deployment uses the same modules with a DR-specific variable file. We verify this by actually deploying to the DR region during testing — not just hoping it works.

DNS Failover: Route 53 health checks monitor your primary region. When health checks fail, DNS automatically routes to the DR region. The failover is configured in Terraform with appropriate TTLs and health check intervals. We test the failover path regularly to ensure it works when needed.

Recovery Testing: We set up a quarterly DR drill pipeline that deploys the full infrastructure to the DR region, restores data from backups, runs smoke tests, and then tears everything down. This validates that your code, data backups, and recovery procedures actually work. The drill results are documented and any issues are fixed immediately.

For teams requiring lower RTO, we implement a warm standby with a minimal infrastructure running in the DR region at all times — a small database replica, a minimal compute cluster, and pre-provisioned networking. Scaling up during a disaster is faster than provisioning from scratch.

A complete disaster recovery strategy backed by infrastructure as code:

• Multi-region Terraform — parameterized modules that deploy identically to any region
• Data replication — S3, RDS, and DynamoDB cross-region replication managed as code
• DNS failover — Route 53 health checks and automatic failover configuration
• Recovery runbook — step-by-step procedure for DR activation and failback
• Quarterly DR drills — automated pipeline that tests the full recovery path
• RTO/RPO documentation — measured recovery metrics from actual drill results
• Backup verification — automated backup integrity checks with alerting on failures