The only error I get when running it as a daemon is found in /var/log/logstash/logstash.err
WARNING: Default JAVA_OPTS will be overridden by the JAVA_OPTS defined in the environment. Environment JAVA_OPTS are -Djava.io.tmpdir=/opt/logstash
That field is commented out in /etc/default/logstash. It looks exactly like the one in init.d/logstash
I've not changed that field.
Not knowing enough about java, is that how it's supposed to be?
The line in the init.d/logstash file relating to that reads like this:
LS_JAVA_OPTS="-Djava.io.tmpdir=${LS_HOME}"
And LS_HOME looks like this:
LS_HOME=/opt/logstash