upstream poolhtml5servers {
  zone poolhtml5servers 32k;
  least_conn;
  server 127.0.0.1:4100 fail_timeout=5s max_fails=3;
  server 127.0.0.1:4101 fail_timeout=5s max_fails=3;
  server 127.0.0.1:4102 fail_timeout=5s max_fails=3;
  server 127.0.0.1:4103 fail_timeout=5s max_fails=3;
  server 127.0.0.1:4104 fail_timeout=5s max_fails=3;
  server 127.0.0.1:4105 fail_timeout=5s max_fails=3;
  server 127.0.0.1:4106 fail_timeout=5s max_fails=3;
  server 127.0.0.1:4107 fail_timeout=5s max_fails=3;
}