Amazon Web Service’s default nginx configuration does not have websocket support enabled by default. I am running SailsJS with Socket.io on NodeJS with the default nginx proxy and discovered that websockets were failing to connect. Creating a directory named .ebextensions in the root of my application and a file named 01_files.config within it with the configuration below solved the problem as it instructs nginx to pass websockets through. Just drop this in, deploy your app, and you should be good to go with your websockets functioning.

.ebextensions/01_files.config contents:

files:
    "/etc/nginx/conf.d/websocketupgrade.conf" :
        mode: "000755"
        owner: root
        group: root
        content: |
             proxy_set_header        Upgrade         $http_upgrade;
             proxy_set_header        Connection      "upgrade";

I searched high and low for a solution to this problem and after finding several similar but functioning solutions I combined them to get the above.