server {
    listen 8081;
    location / {
        root /usr/share/nginx/html;
        index unresolvable-file-html.html;
        try_files $uri @index;
    }

     location @index {
        root /usr/share/nginx/html;
        add_header Cache-Control no-cache;
        expires 0;
        try_files /index.html =404;
    }
}