Ignore "Host not found" in nginx location

[veerendra2]

Ngnix is failing to start if any of specified location is down

/docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration
/docker-entrypoint.sh: Looking for shell scripts in /docker-entrypoint.d/
/docker-entrypoint.sh: Launching /docker-entrypoint.d/10-listen-on-ipv6-by-default.sh
10-listen-on-ipv6-by-default.sh: info: can not modify /etc/nginx/conf.d/default.conf (read-only file system?)
/docker-entrypoint.sh: Launching /docker-entrypoint.d/20-envsubst-on-templates.sh
/docker-entrypoint.sh: Launching /docker-entrypoint.d/30-tune-worker-processes.sh
/docker-entrypoint.sh: Configuration complete; ready for start up
2022/12/27 20:36:03 [emerg] 1#1: host not found in upstream "pihole" in /etc/nginx/conf.d/locations/pihole.conf:2
nginx: [emerg] host not found in upstream "pihole" in /etc/nginx/conf.d/locations/pihole.conf:2
/docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration
/docker-entrypoint.sh: Looking for shell scripts in /docker-entrypoint.d/
/docker-entrypoint.sh: Launching /docker-entrypoint.d/10-listen-on-ipv6-by-default.sh

Solutions

• proxy_read_timeout (https://stackoverflow.com/questions/18740635)
  • Need to set upstream
• try_files?

[veerendra2]

• https://stackoverflow.com/questions/32845674
• https://serverfault.com/questions/935096
  It is only working for down location. If the host is up, it not working

UPDATE; It worked due to browser cache

[veerendra2]

Tried below config

location /admin/ {
  resolver 127.0.0.11 valid=30s;
  set $upstream pihole;

  proxy_pass http://$upstream/admin/;  #http://pihole:80/admin/; #$upstream;
  proxy_set_header Host $http_host;
  proxy_set_header X-Real-IP $remote_addr;
  proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
  proxy_hide_header X-Frame-Options;
  proxy_set_header X-Frame-Options "SAMEORIGIN";
  proxy_read_timeout 90;
}

• Above config is not working in browser with This problem can sometimes be caused by disabling or refusing to accept cookies. and HTTP 302 error, but the endpoint seems up when try with httpie

$  http --verify=no  --check-status https://192.168.0.120/admin/login.php
HTTP/1.1 302 Found
Cache-Control: no-store, no-cache, must-revalidate
Connection: keep-alive
Content-Length: 0
Content-Security-Policy: default-src 'self' 'unsafe-inline';
Content-Type: text/html; charset=UTF-8
Date: Thu, 29 Dec 2022 22:30:27 GMT
Expires: Thu, 19 Nov 1981 08:52:00 GMT
Location: login.php
Pragma: no-cache
Referrer-Policy: same-origin
Server: nginx/1.23.2
Set-Cookie: PHPSESSID=33cobiugh16cqg4i89aus42l8i; path=/; HttpOnly; SameSite=Strict
X-Content-Type-Options: nosniff
X-Permitted-Cross-Domain-Policies: none
X-Pi-hole: The Pi-hole Web interface is working!
X-XSS-Protection: 1; mode=block

• Even the browser gets redirect to https://192.168.0.120/admin/login.php when homer has https://192.168.0.120/admin/
• Tried with upstream with max_fails=3 fail_timeout=30s; and resolver, but no luck!
• DNS resolving is work

veerendra@atom:/opt/apps/nginx$ docker exec -it nginx nslookup pihole 127.0.0.11
Server:         127.0.0.11
Address:        127.0.0.11:53

Non-authoritative answer:
Name:   pihole
Address: 172.18.0.5

Non-authoritative answer:

[veerendra2]

• Working when I remove varaible in proxy_pass
• The nginx is failing to start if it cant resolve the host. Can't found a why how to prevent stopping the host is down. Tried with set too

[veerendra2]

Closing the issue, cant find fix. Maybe switch to caddy in future