InfraHub Multi-CDN

Why Multi-CDN?

Using a single cloud provider exposes your infrastructure to a single point of failure. A notable example is the Cloudflare incident on November 18, 2025. A database permission change caused a critical configuration file to double in size, triggering HTTP 5xx errors across their network. This outage illustrates the importance of redundancy across multiple CDNs.

• Core CDN and security services returned 5xx errors.
• Authentication systems experienced failures.
• Latency increased due to debugging processing errors.

Cloud Single Point of Failure

Any cloud provider can experience hardware failures, software bugs, or misconfigurations. Multi-CDN reduces this risk by distributing traffic and providing failover paths.

Step 1: Primary CDN – CloudFront

CloudFront serves as the main entry point for user traffic, routing requests to the origins you configure (containers, EC2 instances, or S3 buckets). Proper setup ensures reliable delivery.

• CloudFront Developer Guide
• Distributions & Origins

Step 2: DNS with Route 53

DNS resolution works as follows:

1. Enter domain (e.g., www.example.com) in browser.
2. Browser checks local cache for IP.
3. If not cached, query goes to a recursive resolver (ISP or public).
4. Resolver queries DNS hierarchy: root → TLD → authoritative server.
5. Resolver returns IP to browser, which connects to the server.

• Route 53 Developer Guide
• DNS Resolution Explained

After linking CloudFront with Route 53, CloudFront automatically creates an A or AAAA record.

Step 3: Add a Secondary CDN – Fastly

Add a second CDN (e.g., Fastly) pointing to the same origin(s) to allow failover if CloudFront fails.

• Origin can be container, EC2, or S3 as long as it's publicly reachable.
• Fastly gets its own DNS record in Route 53.

• Fastly Documentation
• CDN Setup & Origins

Step 4: Route 53 Health Checks & Failover

1. Create a dedicated, complex domain pointing to the CloudFront distribution for monitoring.
2. Set up a Route 53 health check for this domain.
3. Edit A records of both CDNs in Route 53.
4. Set routing policy to Failover: assign primary/secondary and attach health check ID.

Route 53 will automatically redirect traffic if a health check fails, ensuring full fault tolerance.

• DNS Failover Guide
• Health Checks

Conclusion

Multi-CDN with Route 53 health checks removes single points of failure, keeping your users connected even if one provider fails.