Table of Contents
Look at Logs
If things aren’t happening as expected, please first look at your logs. For td-agent (rpm/deb), the logs are located at
Turn on Verbose Logging
You can get more information about the logs if verbose logging is turned on. Please follow the steps below.
# at /etc/init.d/td-agent ... TD_AGENT_ARGS="... -vv" ...
# at /etc/init.d/td-agent ... DAEMON_ARGS="... -vv" ...
-vv to your command line.
$ fluentd .. -vv
Dump fluentd internal information
Fluentd uses sigdump for dumping fluentd internal information to local file, e.g. thread dump, object allocation and etc.
If you have a problem with fluentd like process hang, please send
SIGCONT to fluentd parent and child processes.
High CPU usage issue
If fluentd suddenly hits unexpected high CPU usage problem, there are several reasons:
- a plugin has a race condition or similar bug
- dependent gems have a bug
- regular expression with broken data
- system calls has a bug, e.g.
inotifywith lots of files
Check uncaught logs
You sometimes hit unexpected shutdown with non-zero exit status like below.
2016-01-01 00:00:00 +0800 [info]: starting fluentd-0.12.28 2016-01-01 00:00:00 +0800 [info]: reading config file path="/etc/td-agent/td-agent.conf" [...snip...] 2016-01-01 00:00:02 +0800 [info]: process finished code=6
If the problem happens inside ruby, e.g. segmentation fault, C extension bug, etc,
you can’t get entire log when fluentd process is daemonized.
For example, td-agent launches fluentd with
--daemon option. In td-agent case,
you can get entire log using following command to simulate
/etc/init.d/td-agent start without daemonize.
$ sudo LD_PRELOAD=/opt/td-agent/embedded/lib/libjemalloc.so /usr/sbin/td-agent -c /etc/td-agent/td-agent.conf --user td-agent --group td-agent
If this article is incorrect or outdated, or omits critical information, please let us know. Fluentd is a open source project under Cloud Native Computing Foundation (CNCF), originally invented by Treasure Data, Inc. All components are available under the Apache 2 License.