Tamper-evident audit log

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  • Lock 17

Difficulty 4 of 5

Services send 5,000 audit events/s, 6 KB each, from 2,000 actors. Each actor's events form a hash chain, appended in order. The chain writer runs in a locked vault in us-east. A log partition carries 10 MB/s. Keep order, lose nothing, p99 under 50 ms, lag under 2 s.

Play level

HTTP/2Users5,000 req/sAPI server2 vCPU · 1 GBWorker1 vCPU · 1 GB × 4
HTTP/2HTTP/2Users5,000 req/sAPI server2 vCPU · 1 GBWorker
The board at the start of the level
A graph for each resourceTap to add or remove the probes

One CPU graph · CPU 40% · disk no graph · the fault is hidden

Goals and limits

Out of order
none
Error rate
under 0.1%
Lost writes
none
Queue lag
under 2 s
p99 latency
under 50 ms
Monthly cost
under 60 USD/mo
Parts you can add
Kafka log, Managed queue, Worker, Message broker
Part limit
6

Concepts

How players did

Player results load from the server.

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