One Build For One Agent

Situation

Set up the build so that one agent runs only one build at a time. If all agents are occupied, the build should be waiting.

Demonstration

1. Check grid tab on the demo site, and there are two agents available.
2. Visit the control project, and hit the run button to trigger all its children (project1, project2 and project3) concurrently.
3. Check the queue tab. Only two child builds will be running, each occupying one agent. The waiting child build will start to run when one of the running child builds finishes.

Resolution

1. Switch to resources tab and a resource named "Agent" is defined with each agent providing one resource.
2. Check master step definition of child project1, child project2, and child project3. They all set to run on node with resource Agent. If resource requirement of the master step is not satisfied, the build itself will be put into waiting state.