{{tag>nginx docker}}

====== Avoid upstream not found in nginx when using only one upstream server ======
If you have a situation where there is only one upstream that you need to proxy_pass, use a variable in the ''proxy_pass'' directive, e.g.

<code nginx>
server {
  listen 80;
  resolver 127.0.0.11 valid=30s; # docker's resolver
  set $target "http://target-host:3005";  # variable definition
  location / { 
    proxy_pass $target; 
  }
}
</code>

This will not error out if the target-host is not available (for example in some Docker setup). 

<WRAP center round help 60%>
resolver is probably needed even when the target host is not a docker container
</WRAP>

The following example however will give you an error if the target-host can not be resolved:
<code nginx>
upstream target {
    server target-host:3005;
}

server {
  listen 80;

  location / { proxy_pass $target; }
}
</code>
====== Tested on ======
  * nginx/1.22.1

====== See also ======
  * [[wiki:nginx_troubleshooting|Nginx troubleshooting]]
====== References ======
  * https://stackoverflow.com/questions/32845674/setup-nginx-not-to-crash-if-host-in-upstream-is-not-found