I was running 6.6.1 on FreeBSD without problems. When updating to 6.7.1 I was unable to start logstash as the logstash user (I never start it as root). I tried as root out of curiosity and it worked.
The complaint was the failure to find a temporary directory. Suspecting some Java temporary directory issue I added this to jvm.options
set the I/O temp directory
But it still didn't work.
Investigating the issue with ktrace I found that during startup it tried to access a directory called /nonexistent. Creating it and changing owner to logstash (the unprivileged user I use for it) it begun working.
Any clues of what could be causing this behavior? I looked over the documentation searching for some new setting and I didn't find anything.
Looks like a JRuby bug?