jameshowe I built a local copy of the Jenkins master branch with pull request 5187 and confirmed that it passes the job that was consistently failing on Jenkins 2.275 and Jenkins 2.263.2. You're welcome to use my build to test or you can use the ci.jenkins.io build that will be generated as part of the pull request.

Oh wow. Thank you markewaite for the quick turnaround! This is a show stopper for us (we have custom scripts that look on these artifacts).  Can't wait for this to be in a TLS (We are only allowed to use TLS versions). (And thank you Oleg for verifying the PR works!)

grayaii, if you are doing automatic downloading of artifacts you should probably have a look at JENKINS-64669 that I just filed. Normal "occasional" downloads might not be enough to trigger problems, but high frequency automated downloads was what triggered it for us. (And zip-on-the-fly downloads might not be affected - I've not investigated that.)

Ouchie. Yeah, that a big one.  We use datadog to monitor open file handles, but I didn't even get that far due to this ticket.
Wow.  Thank you so much for pointing that out.  I just voted for that ticket too. You just saved us a ton of headahe.

Thanks njesper we've run into that issue the past couple of nights after upgrading this weekend.  Upped our limits last night, but good to know we need to keep an eye on this.