In previous Check_MK versions, there was no real user friendly and correcthandling of too long web request processing. So if a user issued a requestto the Multisite GUI which took longer than the system apache request timeout,it resulted in a default webserver error page showing a "proxy timeout" errormessage.
Another issue: The timeout was dependent on your system apache configurationand, if you did not change the settings on your own, on the Linux distributiondefaults.
We have now changed the timeout mechanism as follows:
The system apache process will end the communication with the client afterthe timeout configured for the proxy connection from system apache to siteapache. This is done in /omd/sites/[site]/etc/apache/proxy-port.conf filein the "timeout=x" parameter of the ProxyPass statement. The client timeouthas been configured to 120 seconds.
The application (Check_MK GUI) request timeout should always be lower thanthe client timeout to make it possible to abort the page processing and senda helpful response page to the client. The default timeout is set to 110seconds.
It is possible to disable the applications request timeout (temoporarily)or totally for specific calls, but the timeout to the client will alwaysbe applied by the system webserver. So the client will always get a errorpage while the site apache continues processing the request (until thefirst try to write anything to the client) which will result in anexception.