EBS multi node configuration for Apps Tier with load balancer
A multi node architecture for Oracle EBS is normal for a large enterprise with houndreds of users. This kind of architecture is characterized with both load sharing and high availability. Although It is a three tier architecture with application server and database server, Its application tier is more complex in some way.
There 're form server, report server ,concurrent processing and admin server in addition to the usual Apache server and java server in the middle tier(The application server tier). Which make it more complex to configure load balancing because you have to consider multiple components in the middle tier other than the usual Apache server and java server.
The following graph is a typical architecutre for EBS multi node configuration
For this configuration , The hardware load balancer is neccessary ( might be some kind of software load balancer is also appliable), But you cann't configure a common domain for this architecture without the load balancer.
Suppose we have one application server with domain name 'a1.mydomain.com' and the sencond application server with domain name 'a2.mydomain.com' .
Without the load balancer, The login request will always be redirected to the last application tier where autoconfig has been run!
This is a fact which is not clearly pointed out in Oracle 's documents! So if the last apps tier where we executed autoconfig is down. There 's no way we could login into the EBS even the other apps server is up and normal. And there 's no meaning for high availability with such configuration.
With a load balancer configured with the domain name of 'a.mydomain.com' itself as the common entry for a1 and a2. We could configure apps tier high availability , We could still login into EBS with any of the apps tier !