On 6/8/2018 8:17 AM, Markus Jelsma wrote:

It's not a problem that I've heard of.  There are no Solr classes in the
stacktrace, only Jetty and Java classes.  I won't try to tell you that a
bug in Solr can't be the root cause, because it definitely can.  The
threads appear to be created by Jetty, but the supplied info doesn't
indicate WHY it's happening.

Presumably there's a previous version you've used where this problem did
NOT happen.  What version would that be?

Can you share the solr.log file from both nodes when this happens? 
There might be a clue there.

It sounds like you probably have a small number of collections in the
dev cluster.  Can you confirm that?