Current Setup: Qlik 3.2 on 4 nodes -- 1 central, 2 rims, 1 scheduler.
We were experiencing performance issues with our apps at random times, and we discovered it might be due to our scheduler node not being passed the reload tasks from the central node. Originally, we had our setup such that the central node had a scheduler on it and was set to master and slave with a max of 2 concurrent reload tasks, and our scheduler node had a scheduler on it and was set to slave with a max of 4 concurrent reload tasks. The QMC said all appropriate services were running on the scheduler node, but if more than 2 reload tasks were trying to run simultaneously, we noticed the first two would be handled by the central node, and the third one would be queued. That third reload task was never reaching the scheduler node.
When we tried to set the central node to master only, no reload tasks would run at all, and the QMC would give errors for those reload tasks.
We have tried to restart the services on the scheduler node, but no dice. What are we missing?
It's interesting that the engine must be enabled. I haven't tested that, but I was under the impression that the engine's purpose was calculations only, not reloading. However, I did find out the problem for our particular situation.
Ports. Same as it ever was.
We didn't have the ports opened for the scheduler service to be able to talk to the central node. For anyone else reading this -- if you are setting up Qlik Sense in a multi-node configuration, and something's not working properly, CHECK YOUR PORTS FIRST!!!! Even if you are sure you got them all opened the way you're supposed to, go back and check your ports against the documentation, every time! It should be the first step in your troubleshooting, especially if you have an extra layer of bureaucracy in having sys admins who are in charge of managing those ports. Otherwise, you'll find yourself banging your head against a wall. We've had tons of major headaches with setup, and just about every one of them was due to either not knowing certain ports should be opened or the sys admins not opening the ports like you told them to.