fix: cap cluster worker count via IFRAMELY_WORKERS_COUNT (OOMKilled on large nodes)#4
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graceful-cluster defaults to os.cpus().length workers, which is the HOST node's vCPU count and ignores the container's CPU limit. On large nodes (e.g. 32 vCPU) this forks ~32 workers, each independently loading ~1886 domains + Redis + Secrets Manager, exhausting the pod memory limit -> OOMKilled/CrashLoopBackOff. Pass workersCount to GracefulCluster.start from CONFIG.CLUSTER_WORKERS_COUNT, settable via IFRAMELY_WORKERS_COUNT (alias IFRAMELY_WORKERS). When unset, behaviour is unchanged (falls back to os.cpus().length). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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Problem (customer incident)
iframely's cluster forks
os.cpus().lengthworkers (graceful-clusterdefault). That's the host node's vCPU count and ignores the container CPU limit. On a 32-vCPU node, a pod with a 1000m CPU limit still forks ~32 workers, each independently loading ~1886 domains + connecting to Redis + fetching AWS Secrets Manager. Combined startup memory blows past the pod memory limit → OOMKilled / CrashLoopBackOff within ~40s.There was no supported way to cap the worker count —
cluster.jsnever passedworkersCount, so neither an env var norconfig.local.jscould limit it.Fix
cluster.js: passworkersCount: CONFIG.CLUSTER_WORKERS_COUNTtoGracefulCluster.start.config.loader.js: setCLUSTER_WORKERS_COUNTfromIFRAMELY_WORKERS_COUNT(aliasIFRAMELY_WORKERS).graceful-clusterfalls back toos.cpus().length).This complements the existing
IFRAMELY_WORKER_MAX_MEMORY_MBknob (added in #3): cap the worker count to the CPU/memory the container actually has.Example
Testing
node --checkon both files.0→ignored, non-numeric→ignored — all pass.Note
This is a follow-up to the merged #3 (released as v2.5.2). A customer hit this on 32-vCPU nodes. Recommend cutting a patch release once merged so it can flow through downstream image mirrors.
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