Fix stale nginx upstream keepalive connections causing broken pipe errors - #674
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stephanme merged 2 commits intoJul 30, 2026
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…rors Add keepalive_timeout=15s to nginx upstream block so nginx evicts idle connections before Puma closes them (persistent_timeout=20s), preventing writev() EPIPE errors on stale connections.
stephanme
reviewed
Jul 22, 2026
Replace hardcoded keepalive 32 with cc.puma.workers * cc.puma.max_threads so the pool size always matches the actual Puma concurrency without requiring a separate property.
stephanme
approved these changes
Jul 30, 2026
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A short explanation of the proposed change:
Add keepalive_timeout=15s to nginx upstream block so nginx evicts idle connections before Puma closes them (persistent_timeout=20s), preventing writev() EPIPE errors on stale connections.
An explanation of the use cases your change solves
This change solves the case where nginx reuses an idle upstream connection to Puma that Puma has already closed. Setting keepalive_timeout=15s, shorter than Puma's persistent_timeout=20s, ensures nginx always evicts idle connections from its pool before Puma closes them. The stale connection window is eliminated entirely.
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developbranchI have run CF Acceptance Tests on bosh lite