build - How can I modify the Load Balancing behavior Jenkins uses to control slaves?

Question

We use Jenkins for our CI build system. We also use 'concurrent builds' so that Jenkins will build each change independently. This means we often have 5 or 6 builds of the same job running simultaneously. To accommodate this, we have 4 slaves each with 12 executors.

The problem is that Jenkins doesn't really 'load balance' among its slaves. It tries to build a job on the same slave that it previously built on (presumably to reduce the time syncing from source control). This is a problem because Jenkins will build all 6 instances of our build on the same slave (or more likely between 2 slaves). One build machine gets bogged down and runs very slowly while the rest of them sit idle.

How do I configure the load balancing behavior of Jenkins, and how it controls its slaves?

Answer 1

We were facing a similar issue. So I've put together a plugin that changes the Load Balancer in Jenkins to select a node that currently has the least load - https://plugins.jenkins.io/leastload/

Any feedback is appreciated.