4.3 DNS, CDN and the edge
You can put a domain in front of your service and make it fast for users far away.
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The same thing, three names
One idea, sold under a different brand by each provider. Learn it once and you can read any job advertisement.
- On AWS
- Route 53 + CloudFront
- On Azure
- Azure DNS + Front Door/CDN
- On Google Cloud
- Cloud DNS + Cloud CDN
A domain in front of a service, a CDN in front of the domain, and TLS terminated at the edge — this topic is the last mile between your deployment and a fast experience far away. Managed DNS zones, health-checked routing, cache keys and invalidation are the moving parts. It sits late in the networking module because it composes the earlier pieces into what users actually touch. The common confusion is treating a CDN as a magic accelerator; it caches what your headers allow, and a cache that cannot be invalidated is a bug you shipped to every edge location at once.
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Managed DNS zones, records and health-checked routing
A managed name service holds your domain's records and can route requests based on where a user is or whether a location is healthy. That routing is the foundation of both speed and failover.
CDN caching, cache keys and invalidation
A content delivery network keeps copies near users, and what counts as the same request is decided by the cache key. Getting the key wrong either caches nothing or serves one user's content to another.
TLS termination at the edge
Ending the encrypted connection at the edge lets the network cache and inspect content, and it means the leg behind the edge needs its own protection. Knowing where encryption stops is part of the design.
Origin protection and rate limiting
Once a delivery network fronts your service, the origin should accept requests only from it, and limits should stop one client consuming everything. Otherwise the protection is decoration.
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