OneLinersCommand workbench
Verified diagnostic signature

duplicate upstream

A duplicate upstream name prevents NGINX from loading the configuration. Match this output from nginx, then continue with sourced, read-only checks.

Confidence
high
Platforms
linux
Verified
2026-08-16
Recognized output

Signature matched locally

duplicate upstream

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Likely causes

What usually produces this signal

  1. Two included files define an upstream group with the same name
  2. A backup or generated file is still matched by an include wildcard
  3. A configuration deployment left both the old and new upstream definitions enabled
Safe next checks

Collect evidence before changing the system

01

Validate the NGINX configuration

nginx -t

The output matches the expected target and exits without an error.

02

Dump the resolved NGINX configuration

nginx -T 2>&1 | head -30

The output matches the expected target and exits without an error.