We've got some independent servers, connected behind a hardware balancer. All the machines is running Apache 2.2, Tomcat 5. and mod_proxy_ajp because the connector.

Everything works fine, however when Tomcat is shutdown, Apache returns error code 503 (as it is likely to do, I suppose). The issue is our load balancer, which does not interpret error codes. It simply thinks "oh, server at machine X has clarified -503 blah blah blah, whatever- to my request, it appears to become working, let us keep delivering individuals to that server".

Can there be in whatever way to inform Apache to not return anything within this situation, rather than the 503 error?

It's not possible. Your request balancer sucks. Change it.

Also, 'three tier' does not mean "balancer, apache and tomcat on the top from itInch. Balancer should speak with tomcat directly, and let apache for everyone the static content from the separate domain/server. This could also solve your condition immediately.

Also: goes to serverfault!

I have a similar problem. For me personally the simplest way ended up being to setup Apache to come back a 404 error. To alter the balancer configuration I must send a request towards the Communication department and also to sit awaiting the solution.