Tag: Zero-Downtime

Zero-Downtime Deployments Without Kubernetes: PM2 Rolling Restarts + Nginx Upstream Switching Explained

Feb 18, 2026

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by

Harsimrat Singh

How to eliminate 502 Bad Gateway errors during Node.js deploys using PM2 cluster mode, graceful shutdown signals, and Nginx proxy_next_upstream — no Kubernetes required. You push a critical hotfix at 11 PM. The deploy completes in under five seconds. Then Slack erupts — 502 Bad Gateway. Fourteen users hit the error wall. Your CDN already…