DevOps · Flashcard
Which execution model does Cloudflare Workers use to run code?
- AV8 isolates, with one runtime instance hosting thousands of them at once
- BMicro virtual machines, with one hypervisor hosting thousands of them at once
- COCI containers, with one node's runtime hosting thousands of them at once
- DWebAssembly sandboxes, which are the only supported unit of isolation there
Why this is the answer
Workers run in V8 isolates: a single runtime instance can host hundreds or thousands of isolates and switch between them, which is why per-script overhead is almost nil. Micro-VMs describe Firecracker, the model underneath other FaaS platforms. Containers are the unit for Cloud Run and Fargate, not Workers. Workers do support WebAssembly, but it runs inside an isolate rather than replacing it.
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