Wildfly MOD_CLUSTER tuning

[Sebastian Brack]

Hi All,

we are using Wildfly 25 (with standalone-ha config) with Apache httpd and mod_cluster for load balancing. So far this works good, but there are issues in the details.

If we deploy a new version of our application we make sure at least one cluster node is running so there is no service interruption.

After starting the freshly deployed server mod_cluster registration is already there in Apache before the application is successfully deployed, sometimes leading to HTTP 500 errors in the clients because they are routed to the freshly started server by Apache.

We configured sticky session handling in Apache based on JSESSIONID which works fine.

Is there anyway to handle Apache load balancing in a better way so that only completly deployed app servers are handled? mod_cluster doesn't seem to have additional config settings for such scenarios?

Thanks in advance!

[Sebastian Brack]

After further research it seems that mod_cluster doesn't have support for failover loadbalancing in case of HTTP 500 error codes. mod_proxy does support that tho, so we will dig into mod_proxy a bit more