A generated config file turns one gradual database rollout into repeating edge outages
01Symptom
You run a global edge network. At 11:28 UTC customers start seeing 5xx pages. Your tests catch it by 11:31, and the error rate spikes, falls to baseline, and spikes again every few minutes. You recently weathered record DDoS attacks, so the pattern looks like another one. The status page, which is hosted outside your own infrastructure, also goes down.
02Constraints
- A feature file is pushed to the entire network every few minutes so new bot tactics can be deployed quickly
- A query on a ClickHouse cluster generates that file every five minutes, while the cluster is being updated node by node
- The bot module preallocates memory for 200 features; normal use is about 60
- Two proxy generations are live: the old proxy and the new proxy
- Object storage, identity proxying, and the web login challenge widget all depend on the same core proxy
03Evidence
- The 5xx rate jumps at 11:28, recovers, jumps again, and only later fails continuously
- A database access-control change finished deploying at 11:05, 23 minutes before the first errors
- Every failing new-proxy worker logs `thread new_proxy_worker_thread panicked: called Result::unwrap() on an Err value`
- Failing feature files contain well over 200 features; good files contain about 60
- The file-building query asks for a table's column names without restricting it to one database
- On the new proxy, bot-dependent traffic gets 5xx. On the old proxy, it keeps serving but every bot score becomes zero
- CPU use rises because debugging and observability systems spend it on uncaught errors
- The first hour and a half points at degraded object storage, which is adjacent infrastructure rather than the cause
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Recent
Previously diagnosed.
- No deploy, no traffic change — every internal call fails at exactly 00:00:07tls · mtls · certificates · expiry · observabilityeasy
- Cache hit rate fell to 34% and stayed there. Stopping the rollout 18 minutes in changed nothing.caching · cascading-failure · sharding · control-plane · load-sheddinghard
- One customer's 50,000 req/min spreads across 20 instances. Only shared state sees the whole stream.redis · rate-limiting · distributed-systems · concurrency · slahard
- 100,000 requests in. The counter says 97,832 — every run, a different shortfall.go · concurrency · race-condition · atomics · runtimemedium