Cloudflare - the case study

Boards

The nine boards on one canvas.

Before you start. You need to know that when you open a web address, some machine somewhere has to answer it, and that the nearer that machine is, the faster the page arrives. That is all the background this story needs.

The idea in 30 seconds

Cloudflare stands in front of more than a fifth of the web, and every server it owns runs the same software and answers the same address.
Anycast means one address announced from many cities, with the routing system choosing. Failover comes free; the price is that you can only steer in blocks of 256 addresses.
An isolate is a compartment inside one running program, not a computer: 5 milliseconds and 3 megabytes against a container’s half-second and 35 megabytes.
Spectre cannot be fixed, so Workers freeze the clock instead. No threads and no shared memory are security rules, because a clock is anything that counts.
A Durable Object is one named object, in one place, on one thread. Consistency becomes a property of the address rather than a protocol.
Everything that makes this fast is sameness, and sameness is why a bad regular expression or a doubled configuration file takes down everything at once.

Read the story · Skip to the numbers