Jan 23, 2015 11:43:52 PM hudson.model.Executor run
SEVERE: Unexpected executor death
java.lang.IllegalStateException: /MY_DIR/jenkins/home/jobs/MY_JOB/builds/29 already existed; will not overwite with MY_JOB #29
at hudson.model.RunMap.put(RunMap.java:187)
at jenkins.model.lazy.LazyBuildMixIn.newBuild(LazyBuildMixIn.java:178)
at hudson.model.AbstractProject.newBuild(AbstractProject.java:1001)
at hudson.model.AbstractProject.createExecutable(AbstractProject.java:1200)
at hudson.model.AbstractProject.createExecutable(AbstractProject.java:144)
at hudson.model.Executor.run(Executor.java:213)

I tried to manually start a job via the run button. I see the Dead indicator in the executor status sidebar. I was able to restart the thread and then manually start the job again. This time it started with #30 and appears to be running OK.

Looking at JENKINS_HOME dir in linux, I see that there is a build directory for #29 and the job ran and failed (unrelated). Looking at the Jenkins webpage for the job, the build skips from 28 to (the now running) 30. #29 has no listing.

I know some items related to the major enhancement are not closed yet, like JENKINS-23152, so please close this if the behavior I'm seeing is expected until the next release. If this is unexpected - hopefully this report is informative - this issue happened 4x in a row for each job I had put in the build queue.