title: failed (104: Connection reset by peer) while reading response header from upstream in docker and ubuntu
body: <p>I created a <code>DockerFile</code> like below</p>
  
  <pre><code>FROM ubuntu:18.04
  
  
  MAINTAINER Amin Keshavarz &lt;ak_1596@yahoo.com&gt;
  
  # Add your github access token if needed in composer update as arg or env var.
  ARG github_access_token
  ENV github_access_token=${github_access_token}
  
  
  ENV DEBIAN_FRONTEND=noninteractive
  
  
  # Install dependency packages
  RUN apt-get update &amp;&amp; apt-get install -yq --no-install-recommends \
      git \
      curl \
      ca-certificates \
  #    php \
      php7.2-fpm php7.2-common \
      php7.2-mongodb php-pear php7.2-dev
  
  RUN apt-get install -y build-essential
  # Install mongodb driver
  RUN pecl install mongodb
  #RUN echo "extension=mongodb.so" &gt;&gt; /etc/php/7.2/fpm/php.ini
  #RUN echo "extension=mongodb.so" &gt;&gt; /etc/php/7.2/cli/php.ini
  
  RUN curl -sS https://getcomposer.org/installer | php -- --install-dir=/usr/local/bin --filename=composer
  
  RUN apt-get install -y php7.2-mbstring \
      php7.2-intl \
      php7.2-soap \
      php7.2-curl \
      php7.2-imap \
      php7.2-zmq \
      php7.2-bcmath \
      php7.2-gd \
      php7.2-zip
  
  # Add working directory and copy files into that.
  RUN mkdir /app
  
  VOLUME /app
  WORKDIR /app
  COPY . /app
  
  # Start application installation by composer update command.
  #RUN composer config -g github-oauth.github.com $github_access_token
  RUN composer global require fxp/composer-asset-plugin
  #RUN composer update -vvv
  
  
  ENTRYPOINT service php7.2-fpm start &amp;&amp; /bin/bash
  
  CMD ["php-fpm"]
  
  EXPOSE 9000
  </code></pre>
  
  <p>And using below <code>docke-compose.yml</code></p>
  
  <pre><code>version: "3"
  services:
    web:
      build:
        context: .
        dockerfile: ./docker/Dockerfile
      container_name: "crm_web"
      tty: true
      ports:
        - "9000:9000"
      networks:
        - default
      volumes:
        - .:/app
    nginx:
      image: nginx:1.10.3
      container_name: "crm_nginx"
      ports:
        - 8080:80
      restart: always
      volumes:
        - ./docker/nginx.conf:/etc/nginx/conf.d/default.conf
        - .:/app
      links:
        - web
      depends_on:
        - web
  </code></pre>
  
  <p>And has below nginx.conf</p>
  
  <pre><code>server {
      client_max_body_size 100M;
      set $host_path "/app";
      access_log  /app/log/access.log  main;
  
      server_name  _ localhost;
      root   $host_path/;
      set $yii_bootstrap "index.php";
  
      charset utf-8;
  
      location / {
          index  index.html $yii_bootstrap;
          try_files $uri $uri/ /$yii_bootstrap?$args;
      }
  
      location ~ ^/(protected|framework|themes/\w+/views) {
          deny  all;
      }
  
      #avoid processing of calls to unexisting static files by yii
      location ~ \.(js|css|png|jpg|gif|swf|ico|pdf|mov|fla|zip|rar)$ {
          try_files $uri =404;
      }
  
      # pass the PHP scripts to FastCGI server listening on web:9000
      #
      location ~ \.php {
          fastcgi_split_path_info  ^(.+\.php)(.*)$;
  
          #let yii catch the calls to unexising PHP files
          set $fsn /$yii_bootstrap;
          if (-f $document_root$fastcgi_script_name){
              set $fsn $fastcgi_script_name;
          }
  
          fastcgi_pass   web:9000;
          include fastcgi_params;
          fastcgi_param  SCRIPT_FILENAME  $document_root$fsn;
  
          #PATH_INFO and PATH_TRANSLATED can be omitted, but RFC 3875 specifies them for CGI
          fastcgi_param  PATH_INFO        $fastcgi_path_info;
          fastcgi_param  PATH_TRANSLATED  $document_root$fsn;
      }
  
      # prevent nginx from serving dotfiles (.htaccess, .svn, .git, etc.)
      location ~ /\. {
          deny all;
          access_log off;
          log_not_found off;
      }
  }
  </code></pre>
  
  <p>But when i try to connect my host <code>http://localhost:8080</code> i get below error in my console from docker:</p>
  
  <blockquote>
    <p>crm_nginx | 2018/12/03 14:48:14 [error] 28#28: *17 recv() failed (104:
    Connection reset by peer) while reading response header from upstream,
    client: 172.18.0.1, server: _, request: "GET /web/ HTTP/1.1",
    upstream: "fastcgi://172.18.0.2:9000", host: "localhost:8080"</p>
  </blockquote>
  
  <p>And get <code>502 Bad Gateway</code> in browser.</p>
  
  <p>Can you help me solve this problem?
  What i missed?</p>