change UTC to getLocalTime
logstash 2.1.1
/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-2.1.1-java/lib/logstash/string_interpolation.rb
change @formatter = org.joda.time.format.DateTimeFormat.forPattern(@format)
.withZone(org.joda.time.DateTimeZone::UTC)
to @formatter = org.joda.time.format.DateTimeFormat.forPattern(@format)
.withZone(org.joda.time.DateTimeZone.getDefault())
logstash 2.2.1
/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-event-2.2.1-java/lib/logstash/string_interpolation.rb
change @formatter = org.joda.time.format.DateTimeFormat.forPattern(@format)
.withZone(org.joda.time.DateTimeZone::UTC)
to @formatter = org.joda.time.format.DateTimeFormat.forPattern(@format)
.withZone(org.joda.time.DateTimeZone.getDefault())
useful doc