host not found in up stream

[cedvdb]

I'm trying to run nginx as a reverse proxy inside docker. The issue is that nginx is exiting because it doesn't find the host in upstream (nginx strts faster than keycloak I assume) so it just exits.

docker compose

 version: '2'
 services:
  keycloak:
    image: jboss/keycloak-postgres
    ports:
      - "8080:8080"
  nginx:
    build:
      context: ./nginx
      dockerfile: dockerfile
    ports:
      - "80:80"
      - "443:443"
    depends_on:
      - keycloak
    entrypoint: ['sleep', '25']

 > nginx conf
  server {
    listen 80;

    location / {
      index index.html;
      root /usr/share/nginx/html;
    }

    location /auth {
      proxy_pass http://keycloack:8080/auth;
      proxy_set_header Host $host;
      proxy_set_header X-Real-IP $remote_addr;
      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
      proxy_set_header X-Forwarded-Proto $scheme;
    }
  }

[UpCoder]

have you solved the problems? can you teach me ?thanks!

[stephanlindauer]

@cedvdb which version of docker-compose are you running? i think in older versions depends_on didn't link containers.

[andreif]

Try adding networks, e.g.

version: '2'
networks:
  front:
  back:
services:
  keycloak:
    image: jboss/keycloak-postgres
    ports:
      - "8080:8080"
    networks:
      - back
  nginx:
    build:
      context: ./nginx
      dockerfile: dockerfile
    ports:
      - "80:80"
      - "443:443"
    depends_on:
      keycloak:
        condition: service_started
    entrypoint: ['sleep', '25']
    networks:
      - front
      - back

Also maybe depends_on expects dictionary:

      keycloak:
        condition: service_started

[andreif]

Sorry, I am blind, here is what my awesome colleague wrote to fix it:

    # nginx can't resolve hosts using resolv.conf, and one can't be sure
    # which IP address the nameserver has.
    command: [/bin/sh, -c,
      "export NAMESERVER=$$(cat /etc/resolv.conf \
        | grep 'nameserver' | awk '{print $$2}' | tr '\\n' ' ') && env \
      && echo Creating /etc/nginx/conf.d/resolver.conf \
      using nameserver $$NAMESERVER from /etc/resolv.conf \
      && echo 'resolver' $$NAMESERVER ';' > /etc/nginx/conf.d/resolver.conf; \
      (test -e /etc/nginx/conf.d/default.conf \
       && rm /etc/nginx/conf.d/default.conf); nginx -g 'daemon off;'"]

It would be awesome if Nginx did it natively.

[andreif]

btw, is it alpine image?

[cedvdb]

@andreif I think the docker was an alpine image (I made this question 6 months ago). Thanks!

[andreif]

If it was alpine, then it's related to #78

[imarotte]

I'm having this exact issue. I have 4 computers at work running docker. 2 of them have this issue, two of them don't when running the exact same docker-compose. Any idea what could be causing this?