We are running Jenkins with a master executor and using declarative Jenkins pipeline syntax. We have our project set up as a multi-branch pipeline. Builds are initiated via a webhook from GitHub pull requests. The master executor starts the stage and then delegates to a docker container that is brought up in a docker swarm. When using throttle with 2 maximum total concurrent builds and 1 maximum concurrent build per node, we are able to run more than 2 concurrent builds. Please see the attached images for our configuration and our pipeline