If an Oracle Integration Classic (user-managed) instance is provisioned when the virtual load balancer has temporarily switched from, for example, three IP addresses to one IP address due to a load situation, the instance’s four load balancer access rules are created with only that one IP address even though the virtual load balancer has multiple IP addresses. The access rule ideally should have all load balancer IP addresses in comma-separated fashion.
The missing two IP addresses mean that when the Oracle Integration
Classic instance requests are routed through all load balancer IP addresses to the Oracle Integration
Classic instance, the requests coming from the unknown two IP addresses time out (
504 Gateway Timeout errors). Only requests routed from the registered IP address route successfully.
To resolve this situation, manually disable (from the Oracle Platform Service Manager console) the four load balancer access rules (
ora_lb2ms_8001_1) and add a duplicate set of four rules (with different names) with all load balancer IP addresses included.