Understanding how CDNs work
In order to understand how the cache operates, and for anyone interested in the general topology of the CDN setup, or how to diagnose issues — it's extremely critical to understand how Fastly works in general.
Below are some pages and notes that describe the overall architecture of Fastly, how we leverage it, and why it works the way it does.
<aside> 👉 Heads up: If you're a cache operator, you MUST read and understand the following material!
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<aside> 💡 Insight: You might think Fastly is just "Varnish-as-a-Service" (VaaS), but it's a powerful distributed system loosely based around Varnish and HTTP. Don't let the outward simplicity of our use case deceive you! Complex systems introduce complex dependencies, failure modes, and operational characteristics by nature, not accident.
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Notes on how Fastly is designed
Fastly Varnish ⋆ Mark McDonnell
Thoughts about future integrations
How to program against Varnish & Fastly
Useful links to understand Fastly's Varnish