Build scalable AWS multi-account structures: Organization, security, cost

One AWS account means one security perimeter, shared billing, blast radius spanning everything.

Multiple accounts separate concerns. Prod account for production. Staging account for testing. Dev account for development. Security account for centralized security.

Account structure

Root account: holds billing, reserved instances, organization setup. Nobody works in it.

Security account: centralized logging, guardduty, network firewall.

Prod account: production workloads only.

Staging account: pre-prod testing.

Dev account: development, experiments.

Benefits

Security blast radius limited to one account.

Cost per environment visible.

IAM easier (each account is separate).

Audit trails per account.

Setup

Use AWS Organizations. Create accounts in one command. Set up consolidated billing.

Link accounts with Transit Gateway for inter-account networking.

Centralize logging: SecurityHub, CloudTrail, Config logs in security account.

Cost

Organizations: free. Additional accounts: free to create.

Transit Gateway attachments: £0.05/hour per attachment.

Centralized services: small increase from multi-account overhead.

At 5+ accounts, multi-account pays for itself in operational ease.

Where Critical Cloud comes in

Multi-account complexity grows fast. Cross-account permissions, routing, logging. Requires deep understanding.

We simplify multi-account setups. Single dashboard across all accounts. You see health everywhere.

If multi-account management is overwhelming, see how Critical Support works.