Apache proxy load balancing backend server failure detection

Question

Here\'s my scenario (designed by my predecessor):

Two Apache servers serving reverse proxy duty for a number of mixed backend web servers (Apache, IIS, Tomcat, etc.). T

Answer 1

There is a property 'ping' in the 'BalancerMember parameters'

Reading the documentation it sounds like 'ping' set to 500ms will send a request before mod_proxy directs you to a BalancerMember. mod_proxy will wait 500ms for a response from a BalancerMember, and if mod_proxy doen't get a response it will but the BalancerMember into an error state.

I tired implementing this but it did not appear to help with directing to a live BalancerMember.

    BalancerMember https://api01 route=qa-api1 ttl=5 ping=500ms
    BalancerMember https://api02 route=qa-api2 ttl=5 ping=500ms
    ProxySet lbmethod=bybusyness stickysession=ROUTEID

http://httpd.apache.org/docs/2.4/mod/mod_proxy.html

Ping property tells the webserver to "test" the connection to the backend before forwarding the request. For AJP, it causes mod_proxy_ajp to send a CPING request on the ajp13 connection (implemented on Tomcat 3.3.2+, 4.1.28+ and 5.0.13+). For HTTP, it causes mod_proxy_http to send a 100-Continue to the backend (only valid for HTTP/1.1 - for non HTTP/1.1 backends, this property has no effect). In both cases, the parameter is the delay in seconds to wait for the reply. This feature has been added to avoid problems with hung and busy backends. This will increase the network traffic during the normal operation which could be an issue, but it will lower the traffic in case some of the cluster nodes are down or busy. By adding a postfix of ms, the delay can be also set in milliseconds.