Our production environment consists in n Apache web servers accessed by browsers via a frontal load balancer. Very typical. 99% of our HTTP requests are gracefully handled by this parallelized architecture with no problem.
Unfortunately, 1% of the requests handled by Apache need to access to a tier SOAP webservice, on a foreign server, which is absolutely unable to handle concurrency, resulting in many critical errors.
I'm looking for a way to canalise those SOAP requests through a sort of proxy, able to queue and lock synchronously the requests to the foreign server.
Do standard proxies like Pound, Nginx, Squid or Varnish implement such queues ?