Undertow can be configured to serve static content per host via the location resource. This location resource is exposed to the mod_cluster balancer.
However, all EAP standalone profiles have enabled root location by default. This root location is then exposed to the balancer( Application root "/" is registered).
Root application matches with any application call and therefore mod_cluster balancer is unable to correctly route requests.
To make mod_cluster work, one must delete root location from worker nodes.
or excluding context ROOT
Exclude ROOT context by default