Case Study: Jenkins speeds up CI failure debugging with Undo Live Recorder

Jenkins - Customer Case Study

Jenkins, the open-source continuous integration system, needed a faster way to diagnose failing tests, especially intermittent and hard-to-reproduce issues that often left developers with only a terse error report. Undo’s Live Recorder was used to capture failing test runs so engineers could inspect the exact execution leading up to the failure.

Undo added a small change to the test runner so any failed test would be re-run and recorded to an UndoDB trace file. With Undo’s recording and reverse-debugging, developers could replay the crash, step backward through execution, and identify the root cause quickly: a missing `_PyRandom_Init()` call before command-line parsing in cpython. The result was a much faster path to resolution for CI failures, with the case study highlighting reduced debugging effort and improved handling of both reproducible and intermittent bugs.

Jenkins

Kohsuke Kawaguchi

Founder