Websocket server should listen port 8080. And ELB type should be `application ELB` NOT CLASSIC ONE !

nginx_ws_support.config

files:
  "/etc/nginx/conf.d/01_websockets.conf":
    mode: "000644"
    owner: root
    group: root
    content: |
      upstream nodejs {
        server 127.0.0.1:8081;
        keepalive 256;
      }

      server {
        listen 8080;

        location / {
          proxy_pass  http://nodejs;
          proxy_set_header Upgrade $http_upgrade;
          proxy_set_header Connection "upgrade";
          proxy_http_version 1.1;
          proxy_set_header  Host  $host;
          proxy_set_header  X-Real-IP $remote_addr;
          proxy_set_header  X-Forwarded-For $proxy_add_x_forwarded_for;
        }
      }
  "/opt/elasticbeanstalk/hooks/appdeploy/enact/41_remove_eb_nginx_confg.sh":
    mode: "000755"
    owner: root
    group: root
    content : |
      mv /etc/nginx/conf.d/00_elastic_beanstalk_proxy.conf /etc/nginx/conf.d/00_elastic_beanstalk_proxy.conf.old