>> Jenkins silently and erroneously deletes workspaces on slaves for matrix projects that are not old
We just hit this problem (or what appears to be this problem) as well.

An extract from $JENKINS_HOME/Workspace clean-up.log:

Deleting /Users/dlshudson/jenkins_slave/workspace/dials_distribute on dials-mac-mini
Deleting /scratch/jenkins_slave/workspace/dials_distribute on dials-ws133
Deleting /scratch/jenkins_slave/workspace/dials_distribute on dials-ws154

side-note: it's a shame those log lines are not time-stamped
The 3 mentioned workspaces are from a matrix project, and all workspaces had been accessed recently.

Presumably there is a bug in the workspace cleanup code that means it does not handle matrix projects correctly.

Note that the job configuration specifies 4 slaves: 1 by label, and 3 by individual nodes. The workspaces that were deleted were those on the 3 slaves that were specified as individual notes, but the workspace on the slave that was specified by label was not deleted. Possibly a clue o the bug?

The workaround is to set hudson.model.WorkspaceCleanupThread.disabled=true.

Daniel knows about this area, so assigning to him for comment (sorry, Daniel!)

Since JENKINS-30916 has been closed as a duplicate: Here the ticket description only says that workspaces that aren't old are deleted. In fact a workspace can even be deleted while a build using the workspace is in progress. The lines from the system log for such a case:

Okt 13, 2015 3:29:27 AM INFORMATION hudson.slaves.CommandLauncher launch
slave agent launched for BonefishMac-Ubuntu-12.04
Okt 13, 2015 3:31:15 AM INFORMATION hudson.model.AsyncPeriodicWork$1 run
Started Workspace clean-up
Okt 13, 2015 3:31:21 AM INFORMATION hudson.model.Run execute
Bar-Nightly/label=Ubuntu-12.04 #222 main build action completed: FAILURE

bonefish Same reason, workspace cleanup uses the root workspace directory modification date to determine whether it's old. As matrix jobs only build in subdirectories (corresponding to axes), it's trivial for these to appear unmodified for a long time.

I experienced this bug last night. The workspace of a matrix job was deleted while the job was running.

We are running Jenkins 2.40 with Multi-Branch Project Plugin 0.3.

Please could this issue be assigned to someone?

davida2009 In the absence of a proper fix, we are using the workaround described in my earlier comment, and that works for us.

Matthew, please forgive my ignorance but where do I set hudson.model.WorkspaceCleanupThread.disabled=true?

davida2009 It's passed as a Java system property when you start Jenkins. Something like:

java -Dhudson.model.WorkspaceCleanupThread.disabled=true -jar jenkins.war

See https://wiki.jenkins-ci.org/display/JENKINS/Features+controlled+by+system+properties

Exactly how you change this on your system will depend on how you installed Jenkins, and what scripts you use to start it.

Thanks for your help Matthew.

Thanks to all who wrote on this bug in 2017. I think the recent activity helped me find this bug when I searched for something to explain what was happening. This workaround does seem to work and I'm very grateful.  

Respectfully, I only wish I'd found it when I searched for the same, last year. 

Also experienced for scripted pipeline (on master-only Jenkins installation): I think this issue should really just be fixed (instead of being addressed by implementing one of the various possible and more or less nice workarounds), especially because I hope it should not be too difficult for a Jenkins (core) developer? => I dare to put my money on jglick

According to https://github.com/jenkinsci/jenkins/blob/master/core/src/main/java/hudson/model/WorkspaceCleanupThread.java (see #shouldBeDeleted() method) there is "only special" support for AbstractProject (and thus FreeStyleProject) – but even that is IMHO not 100% safe (only the workspace on the node of the last build is kept, i.e. in case of concurrently running builds it may delete the non-last still running one too)...

My naive search in Jenkins JavaDoc only showed a very easy (but unfortunately also non-perfect) possibility, based on
http://javadoc.jenkins-ci.org/hudson/model/Job.html#isBuilding--

if (item instanceof Job<?,?>) {
  Job<?,?> j = (Job<?,?>) item;
  if (j.isBuilding()) {
    return false;
  }
}

Here the problem might be that old workspaces on other nodes might never be deleted, I think. (Maybe that might be nonetheless still better than the current behaviour.)

=> Actually only in case when Job#isBuilding() returns true, then all the (possible concurrent) running builds need to be checked and only their (active) workspace should be skipped from deletion? => Therefore still hoping and praying for Jesse...

(Very) naive PR: https://github.com/jenkinsci/jenkins/pull/3444

I, too, have been seeing this happen recently.  It's happening on slave jobs (they are restricted to which slave they run on and this configuration never changes) but also on jobs utilizing Publish over SSH plugin for copying files to/from other machines and executing commands via SSH Publishers.

We run under tomcat - I'm not sure how to affect a change in this troubling behavior.  The workarounds mentioned there don't look like something I can use.  If anyone has guidance, I'm all ears.

rupunzlkim to your problem report, can you please add the version of Jenkins you are running.

also seeing this happen recently, version 2.60.3

Sorry for the delay.  The version that we've noticed this on is 2.7.4

Code changed in jenkins
User: Reinhold Füreder
Path:
core/src/main/java/hudson/model/WorkspaceCleanupThread.java
http://jenkins-ci.org/commit/jenkins/f258aff7a736a81306ecb7d3c56cacc9b3a09a68
Log:
JENKINS-27329 Less aggressive WorkspaceCleanupThread (#3444)

• JENKINS-27329 Less aggressive WorkspaceCleanupThread

I dare to claim that the default behaviour of WorkspaceCleanupThread is too aggressive => this little change is by no means perfect (or admittedly even far from perfect), but IMHO a saner or slightly more defensive default behaviour.

Mind that according to https://github.com/jenkinsci/jenkins/blob/9e64bcdcb4a2cf12d59dfa334e09ffb448d361e9/core/src/main/java/hudson/model/Job.java#L301 this "only" checks whether or not the last build of a job is in progress, while the JavaDoc says "Returns true if a build of this project is in progress." (cf. http://javadoc.jenkins-ci.org/hudson/model/Job.html#isBuilding--)

• Fix compilation

• Dummy commit to trigger pipeline

Previous pipeline execution (https://ci.jenkins.io/blue/organizations/jenkins/Core%2Fjenkins/detail/PR-3444/2/tests) failed with one failing test that at first glance appears to be unrelated with my change(s) and looks like a flaky test?

• Add fine logging message

*NOTE:* This service been marked for deprecation: https://developer.github.com/changes/2018-04-25-github-services-deprecation/

Functionality will be removed from GitHub.com on January 31st, 2019.

Fix has been applied in 2.125. IMHO the fix is not complete for parallel AbstractProject builds, but it is better than nothing. Will create a follow-up ticket

danielbeck this thing is marked as RFE in the changelog, but I think this is a bug. Would you agree if I recategorize it?