Long log lines read by fluentd are split into several documents sent to Elasticsearch

Issue

• How to make docker's max log line (of 16Kb) configurable?
• Why do long lines in my container logs get split into multiple lines?
• The max size of the message seems to be 16KB therefore for a message of 85KB the result is that 6 messages were created in different chunks;
• Fluentd is configured with the default configuration (docker json-file log driver).