Apache configuration requirement when we upgrade to the ALB

[hans-zand]

When did the performance test after upgrade the Classic load balancers(CLB) to Application load balancers(ALB), metric shows that, there were about 5% 5xx-errors.

here is the list of the issues:

Timeout was 60 seconds, which is the same as ALB timeout. so apache terminate the connections before the ALB
CPU usage in the dispatchers is too high and instances keep terminating before scale-up
The maximum number of keep-alive requests was low, so the queue will be full and connections will time out with 5xx error