Fluentd Regular Expression Matching Error
From what I can see, you are missing something in the fluentd config.
Your time_format %Y-%m-%d %H:%M:%S will not work with the timestamp 2018-08-14 13:21:20.013, as it's missing .%3N.
It should be as follows:time_format %Y-%m-%d %H:%M:%S.%3N or time_format %Y-%m-%d %H:%M:%S.%L
Just faced a similar issue.I think the @Crou's answer is correct but maybe try %N instead.according to the document, fluentd parser does not support %3N, %6N, %9N, and %L