View the original community article here
Last tested: Jan 5, 2018
Schedule execution is distributed equally across the cluster. Each node will run the scheduler thread amount (default 10 per node and 2 render tasks per node).
For example, if you have a 3 node cluster with default settings, you can have 30 concurrent schedules (assuming none were rendered tasks) or 6 concurrent schedules (if they are rendered tasks). You can change default scheduler thread and render job limit with startup flags on Looker.