The Illusion of Regional Disaster Recovery: Lessons from the AWS us-east-1 Incident

TL;DR

The AWS incident in the us-east-1 region on October 20, 2025, caused widespread service disruptions, even for workloads hosted in other regions. This wasn’t just a cloud architecture challenge; it was also a FinOps wake-up call. Regional control plane dependencies can hinder recovery, visibility, and cost governance during outages. This post explores the technical underpinnings of the event and highlights why automation and FinOps must be central to any resilience strategy.

A Global Disruption with Regional Roots

In the early hours of October 20, 2025, AWS experienced an operational event in the us-east-1 region. DNS resolution issues affecting DynamoDB led to cascading impacts across key services like IAM, Route 53, EC2, and CloudWatch. The effects were felt worldwide by services such as Snapchat, Roblox, and several public-sector systems.

Even customers with infrastructure in other AWS regions experienced issues due to how certain global services are orchestrated. Many global services within AWS leverage centralized control planes, which in this case created unexpected challenges.

The Multi-Region Misconception

Deploying across multiple regions is a common resilience strategy. However, regional redundancy must be paired with awareness of which control operations depend on specific regions. Without that understanding, workloads may still be vulnerable to outages outside of their immediate geography.

Services that appear regional in design may still rely on a single region for metadata or orchestration logic. This can create hidden dependencies that surface only under stress.

For FinOps professionals, this means ensuring that your automation, cost controls, and visibility pipelines can function during regional disruptions.

Technical Context: What Actually Happened

The event began with DNS resolution delays for DynamoDB endpoints in us-east-1, leading to cascading effects:

• IAM operations paused due to their control plane locality
• Route 53 DNS record updates stalled (though the data plane continued operating)
• Global Tables in DynamoDB saw replication and coordination delays
• Services dependent on metadata, like Lambda and CloudWatch, were impacted

These disruptions illustrate how control plane concentration can introduce points of failure, even when infrastructure in other regions remains unaffected.

Preemptive Design for Control Plane Awareness

Here’s a breakdown of key services and their regional control plane dependencies:

Service	Control Plane Location	DR Considerations
IAM	us-east-1 only	Role creation and updates blocked
Route 53	us-east-1 only	DNS record changes paused
Organizations, CloudFront	us-east-1 only	No changes to configuration or org structure
CUR & Billing	us-east-1 only	Spend tracking delayed
STS	global default to us-east-1	Prefer regional endpoints

What Can You Do?

1. Pre-Provision Everything

AWS’s guidance is clear: “Do not rely on the control planes of partitional services in your recovery path. Instead, rely on the data plane operations of these services”. This means:

• Pre-create all IAM roles and policies needed for DR scenarios
• Pre-provision all infrastructure in your DR region
• Don’t rely on auto-scaling that requires new IAM roles
• Set up DNS records in advance with weighted routing, not health-check-based updates

2. Use Regional Endpoints Where Available

For STS, configure your SDKs and CLI to use regional endpoints rather than the global endpoint. While IAM’s control plane remains in us-east-1, you can at least avoid the global STS endpoint dependency.

3. Implement “Break Glass” Procedures

Create emergency “break-glass” IAM users with pre-configured credentials that don’t require STS token generation during an incident. Store these securely and test them regularly.

4. Consider AWS Application Recovery Controller (ARC)

AWS Application Recovery Controller provides a managed multi-region recovery service that can help with Region switch capabilities. However, note that ARC itself has control plane operations that depend on specific regions.

5. Design for Degraded Control Plane Scenarios

Accept that during a us-east-1 outage, you may only have data plane operations available. Design your DR procedures to work within these constraints:

• DNS changes may not be possible – can you use weighted routing instead?
• New resource creation may be limited – do you have enough capacity pre-provisioned?
• IAM changes won’t work – are all necessary permissions already in place?

6. Evaluate Multi-Cloud Strategies

For critical workloads with stringent availability requirements, consider multi-cloud architecture. As one analyst noted

While multi-cloud adds complexity and cost, it’s the only way to truly eliminate single-cloud provider dependencies.

7. Document and train teams on failover playbooks. Don’t rely on the knowledge of specific stakeholders to understand what to do in a downtime. Make sure that the affected services are mapped properly and everyone knows what to do in case a failover is needed.

FinOps Under Pressure: Visibility and Response Gaps

During the incident:

• Cost and Usage Reports were delayed
• Billing APIs became inaccessible
• Automated controls relying on IAM or STS could not execute

From a FinOps perspective, this disrupted not just visibility but decision-making. When billing and usage data are unavailable, teams must rely on alternative telemetry sources, such as CloudWatch metrics, CloudTrail logs, and historical baselines, to understand systemic behavior changes and approximate financial impact. These tools become vital during DR events where cost signals are delayed.

Additional FinOps considerations include:

• Monitoring shifts in infrastructure utilization through system metrics rather than spend
• Using pre-defined usage thresholds and alerts to flag anomalies
• Maintaining a map of critical services and their cost attribution in each region
• Ensuring business continuity decisions are supported by operational signals when financial ones are lagging
• Avoid relying on real-time infrastructure creation or scaling in a secondary region during a DR event. Stand up warm standby environments that are periodically tested. There is a discussion of how you balance the business needs and not being wasteful, but that’s a topic for another blog.

For FinOps, the inability to monitor or act on available cloud costs and policies meant increased exposure. This underscores the need to build financial operations processes that can tolerate temporary lapses in telemetry or control.

Automation as a Resilience Enabler

Resilience isn’t just about uptime, it’s also about operational consistency under failure conditions. Automation enables:

• Pre-validated infrastructure readiness
• Policy enforcement even in degraded states
• Data-plane-only operations during control plane outages

FinOps automation must evolve to:

• Tolerate telemetry delays
• Fall back to historical spending profiles
• Execute predefined workflows without relying on IAM or real-time CUR access

It is not just about knowing where your pitfalls are, but it is the ability to quickly understand the status of your infrastructure once things are going back to normal. Don’t trust manual scanning of the environment to understand shifts in costs and financial impact, make sure you have the right automation ready to flag any inconsistencies and anomalies in infrastructure usage over the span of the incident. This enables your team to automatically identify the next action items required to return to financial certainty.

Building for Operational Continuity

The us-east-1 incident highlighted the impact of regional dependencies within global cloud architectures. While AWS’s model supports global scalability and operational consistency, certain control plane centralizations can pose risks during isolated failures.

Architects and FinOps leaders should:

• Incorporate control plane locality into DR planning
• Simulate outages with telemetry and IAM constraints
• Align automation and financial governance to degraded-mode operations

Actionable Checklist

• Audit control plane dependencies per service
• Use regional STS and pre-created IAM assets
• Simulate failure of global service APIs
• Automate fallback and DR workflows based on static configurations
• Ensure FinOps tooling has local data redundancy and offline visibility options

No platform is immune to operational complexity. Planning for it, and aligning both architectural and financial strategies accordingly, is the key to sustainable resilience.