nginx 502: Debugging Cross-Compose Container DNS Resolution
Service names aren't resolvable across Compose projects — you need to add a network alias so nginx can find the container.
#nginx
5 postsnginx Restarted Fine, but Cloudflare Keeps Returning 502 — Even Though the Origin Is Healthy
A brief error during nginx restart caused Cloudflare to mark the origin as unhealthy and stop forwarding requests, returning 502 on its own. The key clues: localhost hits to the origin return 200, and nginx access logs are completely empty. Just wait for Cloudflare to automatically re-check the origin — it recovers on its own.
Managing Multi-Service Reverse Proxy with nginx conf.d: A Daodao Case Study
A monolithic nginx.conf becomes unwieldy as services grow. Splitting it into per-service files under conf.d/ via include is the standard solution.
nginx First Request Always 502, All Subsequent Requests Fine
When nginx uses the `set $variable` pattern for dynamic upstreams, the DNS cache expires every 30 seconds — the first request after expiry hits a 502 because no IP is available. Upgrading to nginx 1.27.3 and switching to an upstream block with the resolve parameter fixes this: DNS updates happen asynchronously in the background.
Cloudflare Free Plan Maintenance Page: Custom Error Pages Unavailable, Use a Worker Instead
Cloudflare Custom Error Pages require a paid plan. On the Free Plan, use a Worker with inline HTML to intercept 5xx responses instead.