AWS Application Recovery Controller (ARC) Region Switch now lets application teams execute self-service regional failover even when ingress traffic flows through centrally managed proxy fleets. The pattern combines Transit Gateway peering, Route 53 Private Hosted Zones, and VPC Lattice to preserve security guardrails while removing cross-team coordination during disaster recovery.
Architecture Overview
The solution separates the control plane from the data plane. A central networking team owns the ingress proxy fleet — typically Network Load Balancers or third‑party appliances — that terminates external TLS and enforces WAF rules. Application teams own the backend services deployed across primary and standby Regions. ARC Region Switch sits in the application team's account and orchestrates the failover of those backend endpoints without touching the central ingress layer.
Transit Gateway connects the central ingress VPC to each application VPC in both Regions. Peering attachments carry traffic from the proxies to the active Region's workload. Route 53 Private Hosted Zones, associated with the application VPCs, hold the internal DNS names that the proxies resolve. When ARC Region Switch initiates a failover, it updates the Private Hosted Zone records so the proxies automatically route to the standby Region.
VPC Lattice adds a layer of service‑to‑service connectivity that works across accounts and VPCs. Application teams register their services as Lattice targets; the central ingress proxies forward to the Lattice service DNS name. Lattice handles the cross‑Region routing shift when ARC updates the underlying target groups, keeping the proxy configuration static.
Step‑by‑Step Implementation
Provision a Transit Gateway in the central networking account and share it with application accounts via Resource Access Manager. Create peering attachments from the Transit Gateway to each application VPC in the primary and standby Regions. Configure static routes in the Transit Gateway route tables so traffic from the ingress VPC reaches the correct application VPC CIDR.
In each application account, create a Route 53 Private Hosted Zone (for example, app.internal) and associate it with the application VPCs in both Regions. Deploy ARC Region Switch (a CloudFormation stack or CDK construct) that manages a Routing Control for the application. The Routing Control's health checks monitor the primary Region endpoints; when triggered, ARC updates the Private Hosted Zone's weighted alias records to point to the standby Region's load balancer or Lattice service IP.
Register the application endpoints as VPC Lattice services in both Regions. Configure the central ingress proxies to forward traffic to the Lattice service DNS name (e.g., my‑service.lattice.us-east-1.on.aws). Because Lattice resolves to the active target group, the proxies require no configuration change during failover. Test the end‑to‑end flow by invoking the ARC Routing Control and verifying that DNS resolution shifts within the configured TTL.
Operational Guardrails
Restrict ARC Routing Control permissions with IAM conditions so only designated application team roles can initiate failover. Use Service Control Policies to prevent modification of the central Transit Gateway attachments or Route 53 Private Hosted Zone associations. Enable CloudTrail data events on Route 53 and ARC to audit every failover action.
Configure health checks that reflect true application readiness — not just TCP reachability. ARC supports Route 53 health checks, CloudWatch metric alarms, and custom Lambda validators. Set evaluation periods and thresholds that avoid flapping while meeting your RTO. Document the runbook: who can trigger, escalation path, and post‑failover validation steps.
Monitor the end‑to‑end latency from ingress proxy to backend after failover. VPC Lattice emits CloudWatch metrics for target group health, request count, and latency. Set alarms on error rate spikes and latency percentiles. Run quarterly DR drills that exercise the full ARC Region Switch workflow, including rollback to the primary Region.
What to do next
Start by inventorying your centralized ingress proxies and mapping each application's primary/standby Regions. Deploy the Transit Gateway peering and Private Hosted Zone foundation once, then onboard applications incrementally using the ARC Region Switch CloudFormation template. Schedule a tabletop exercise this sprint to validate the runbook.
FAQ
Does ARC Region Switch require the central networking team to change proxy configuration during failover?
No. The proxies resolve the application's internal DNS name (Private Hosted Zone or VPC Lattice service DNS), which ARC updates automatically. Proxy configuration stays static.
Can this pattern work with third‑party ingress appliances instead of AWS Network Load Balancers?
Yes. Any appliance that forwards based on DNS resolution — and respects TTL — works. The key is that the appliance points to a Private Hosted Zone or Lattice DNS name managed by ARC.
What is the typical failover time with this architecture?
Failover time equals the DNS TTL (commonly 60 seconds for Private Hosted Zones) plus ARC Routing Control propagation (usually under 30 seconds). End‑to‑end RTO typically falls in the 90–120 second range.
Source: Self-service regional failover with Amazon Application Recovery Controller Region Switch and centralized ingress controls (AWS).
