[ILUG] Apache Load Balancer Monitoring

[Peter Finch]

Hi,

I am running Apache as a load balancer in a production environment. I have 
set up load balancers using the apache ProxyPassMatch and <Proxy> 
directives, e.g.

 	ProxyPassMatch ^(?i)/Test(.*)$  balancer://testcluster/Test$1

         <Proxy balancer://testcluster>
                 BalancerMember http://10.10.10.1 route=node1
                 BalancerMember http://10.10.10.2 route=node2
                 BalancerMember http://10.10.10.3 route=node3
                 BalancerMember http://10.10.10.4 route=node4
                 ProxySet lbmethod=byrequests
         </Proxy>

All works great, but I wish to monitor the environment more closely. Apache
can mark BalancerMembers as not ok an stop using them, I would like to 
know when this happens. I could do this using the following methods:
1) tail the apache error log and alert on problems in there, I can't 
however find an appropriate log entry to do this with, even if I could i'm 
not sure this is a good solution anyway.
2) grab the apache provided "Load Balancer Manager" page and check if 
BalancerMember statuses are not ok.

Does anyone know if there is a nicer way to do the above. And does anyone 
have any tips on general realtime monitoring in apache?

Peter