What Happened (and Why It Hurt So Many Apps)
On October 20–21, 2025, AWS experienced a widespread disruption centered in us-east-1. The immediate trigger was DNS resolution failures for the DynamoDB API endpoint, which cascaded into issues for multiple AWS services and customers that depend on DynamoDB and related control/management planes. As services retried and dependencies stacked up, the blast radius widened to popular apps and internal AWS functions before stabilization later in the day.
AWS’ public updates and independent reporting consistently pointed to the same root: DynamoDB endpoint DNS resolution breaking in us-east-1, alongside downstream effects (e.g., load balancer health/launch and other services coupled to regional dependencies).
Put simply: the “phone book” couldn’t reliably resolve a critical service, which caused a cascade of service failures.
If you felt this in Slack, Zoom, Atlassian, Snapchat, and others, you weren’t alone. A long tail of SaaS and enterprise backends either degraded or failed outright during the event. AWS later said services had returned to normal, but the outage renewed scrutiny on single-region and single-provider dependencies.
Why a DNS Glitch Knocked Over So Many Dominos
Hidden single points of failure. Many workloads concentrated control-plane and data-plane dependencies (e.g., IAM updates, global tables, service discovery) on us-east-1—often for historical or latency reasons. When DNS resolution to DynamoDB faltered, it starved control planes and broke app data paths.
Service chaining & retries. Microservices that rely on SDKs with exponential backoff can inadvertently create thundering herds (an overwhelming amount of requests that come after a delay), amplifying an already stressed subsystem. ThousandEyes and others observed the ripple effects at Internet scale.
DNS is critical path. If your resolver path or provider-hosted private DNS can’t return healthy answers—and your clients don’t have alternate resolvers/records—failover becomes theory, not practice.
The Uncomfortable Truth
Even world-class clouds have bad days. What matters for you is designing blast-radius boundaries and escape hatches so your business stays up while a provider recovers.
That’s exactly where Aviatrix Cloud Native Security Fabric (CNSF) shines.
How Aviatrix CNSF Reduces Your Outage Blast Radius
Below are concrete ways Aviatrix would have helped customers either continue serving traffic or recover faster during this event—and how to design for the next one.
1) Multicloud transit with deterministic, policy-based routing
Problem: If your east-coast AWS region can’t resolve or reach a core service, you need the ability to steer traffic to an alternative region or cloud (Azure, GCP, OCI) where equivalents are healthy.
Solution: Consider multicloud solutions that don’t rely on a single cloud service provider (CSP). CSPs offer 99.9% service reliability for any service before they offer service credits. You only get to 100% payback for the month when they get below 95%, which is about 36 hours of down time in a month. Most of the CSPs recommend using multiple Availability Zones/Regions for failover.
CNSF capability:
Aviatrix Transit & Spoke Gateways build a provider-agnostic data plane that can be tuned per-application. You can pre-establish active/standby or active/active paths between AWS and other clouds—then flip traffic in seconds using centralized policy controls, not bespoke route-table surgery.
Encrypted, high-performance overlays keep your intercloud paths consistent without exposing internal networks.
Outcome: When AWS DNS → DynamoDB resolution failed, apps with warm paths into Azure/GCP equivalents (e.g., Cosmos DB/Bigtable, or even a read-only cache) could shift API calls via Aviatrix policy—without redeploying network components mid-incident.
Caveats: You’ll need to have your application running duplicate services in multiple clouds. If you are reliant on cloud native services, you’ll need to ensure an analogue is available with another CSP and handle data migration/replication at scale. The good news is that Aviatrix CNSF runs in all the CSPs. We can handle the network heavy lifting securely and at scale. We can’t write your application, but we can make sure traffic gets where it needs to go.
2) Segmentation and least-privilege routing to contain control-plane dependencies
Problem: Over-centralized control-plane lack of reachability (IAM, STS, KMS, DynamoDB Global Tables) increases blast radius.
CNSF capability:
Distributed Cloud Firewall (DCF) and segmentation let you separate control-plane traffic from app data paths and constrain which VNets/VPCs can reach which endpoints, in which regions/clouds.
Combined with multi-region attachments, you can preserve east-west functionality even if north-south (provider control plane) is impaired.
Outcome: Your internal east-west services can keep running while control-plane catch-up happens in the background.
3) Observability that tells you where to fail over (not just that you’re down)
Problem: During incidents, teams waste precious time guessing: “Is it DNS? App? Database? Network?”
CNSF capability:
Aviatrix CoPilot provides flow-level visibility, path health, and topology across all clouds. You see which flows are failing at which hop (resolver, API endpoint, NAT/egress, etc.).
Export NetFlow/IPFIX/OTel to your SIEM/observability stack for forensics and runbooks.
Outcome: Faster diagnosis → faster, safer failover decisions → shorter outages.
4) Portability via automation
Problem: If your only database/queue/cache lives in one provider and region, your RTO/RPO depend on their day.
CNSF capability:
Keep network landing zones and security posture consistent across providers via Terraform/automation with Aviatrix.
Make the network boring and repeatable so apps can multi-home: primary in AWS, warm standby in Azure/GCP, or read-mostly replicas elsewhere.
Outcome: Pre-wired portability turns a provider outage into a traffic steering exercise, not a fire drill.
A Prescriptive Playbook for Practitioners: Creating Resilience through Aviatrix
Day 0 (Design)
Multicloud transit baseline: Build Aviatrix Transit in AWS and one secondary cloud. Attach spokes for the tiers you can realistically fail over (web/API, not necessarily stateful writes on day one).
Dual DNS resolver strategy: Operate two resolver paths and use secondary DNS caches. Keep TTLs low-but-sane on the primary resolver (if running in AWS will need to be Route53). Use DNS caches and overwrite the TTLS to something much longer like 604,800 (7-days) for the DNS entries you own and point your caches at another DNS Service Provider.
Warm data paths: For stateful tiers, start with read replicas or event-sourced feeds in a second cloud—even if write cutover remains a manual decision.
Runbooks + tests: Quarterly game days to exercise DNS failover, policy flips, and rollback.
Day 1 (During incident)
Use Aviatrix CoPilot to confirm where paths are failing. If DNS/DynamoDB in us-east-1 is the bottleneck, flip resolver path or shift API traffic to healthy region/provider using Aviatrix policy.
Throttle non-critical retries to avoid self-inflicted DDoS.
Prioritize customer-facing read paths first (serve cached content, read replicas) while writes queue/degrade gracefully.
Day 2 (Post-mortem hardening)
Inventory every provider-locked endpoint in your critical path and give it a multicloud/region alternative.
Bake DNS failover and policy flips into CI/CD pipelines with change-control guardrails.
Would Aviatrix have “prevented” the outage?
No vendor can prevent a provider’s internal DNS or database endpoint from failing. But with Aviatrix, you can contain the blast radius and keep serving traffic by:
Steering around a failed resolver chains and services
Failing over to a healthy region/provider
Observing the problem quickly enough to act with confidence
Determine root cause and the need for recovery/failback
That’s the practical definition of resilience.
Final takeaways
The root trigger was DNS resolution failures to DynamoDB in us-east-1, with cascading impacts across dependent services. Design as if that can and will happen again.
Multicloud networking + application segmentation = smaller blast radius and faster failover.
Aviatrix CNSF gives you the deterministic, policy-driven controls and visibility you need to execute that strategy—before the next bad day.
Schedule a demo to learn how CNSF provides network-wide visibility, segmentation, and resiliency.
