Hi, I am using a custom 200 response file so that my upstream load balancer can determine if my haproxy instance is operating correctly.
errorfile 200 /home/haproxy/responses/200_resp.http Additionally I am using the monitor-uri /healthcheck. So when my upstream load balancer calls haproxyhost:port/healthcheck haproxy will return the contents of the 200_resp.http file. This all works fine, however if I change the contents of the 200 response file when haproxy is running I have noticed that haproxy is actually caching this file. The caching part is fine, however in order for haproxy to see the updated response file I must restart/reload haproxy so it picks up the new contents. You might be asking why am I changing this file? Well basically if I need to perform rolling restarts on my haproxy instances I need a method of signaling the upstream load balancer health check to remove the haproxy instance from the available pool. So if I change the contents of the 200 response I can basically automatically remove the haproxy instance from the pool and traffic will no longer flow to the haproxy instance. However, because haproxy caches this file I need to restart/reload haproxy. I would like to not have to perform this restart though. Is there any way to signal haproxy to invalidate the error file cache and reread the errorfiles without restarting? Can this be done through the stats socket? Is anybody else doing this and have a better method? How do I make a feature request if this functionality is not available? thanks, Corey Osman
