Plugin Management
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This article explains how to manage Fluentd plugins, including adding 3rd party plugins.
The fluent-gem command is used to install Fluentd plugins. This is a wrapper around the gem command.
Ruby doesn't guarantee C extension API compatibility between its major versions. If you update Fluentd's Ruby version, you should re-install the plugins that depend on C extension.
If you are using td-agent, please make sure to use td-agent's td-agent-gem command. Otherwise (e.g. you use the command belonging to system, rvm, etc.), you won't be able to find your "installed" plugins.
Please see for more information.
Some plugins depend on natvie extension library. It means you need to install development packages to build it, e.g. gcc, make, autoconf and etc. If you see logs like below, install development packages before plugin installation.
Fluentd's -p option is used to add an extra plugin directory to the load path. For example, if you put the out_foo.rb plugin into /path/to/plugin, you can load the out_foo.rb plugin by specifying the -p option as shown below.
You can specify the -p option more than once.
Fluentd adds the /etc/fluent/plugin directory to its load path by default. Thus, any additional plugins that are placed in /etc/fluent/plugin will be loaded automatically.
For example, if /etc/fluent/plugin/out_foo.rb exists, you can use @type foo in <match>.
If you are using td-agent, Fluentd uses the /etc/td-agent/plugin directory instead of /etc/fluent/plugin. Please put your plugins here instead.
Fluentd and plugins are evolving, so you may hit unexpected error with latest version, e.g. regression by new feature, removed deprecated parameter,, change library dependency, etc. Avoiding these problems, we recommend to fix fluentd and plugin version on production. If you want to update fluentd or plugins, check the behaviour first on your test environment. For example, td-agent fixes fluentd and plugins version in each release.
Fluentd plugins are rubygems and rubygems installs latest version by default. So we don't recommend to execute following commands on production:
gem install fluentd
gem install fluent-plugin-elasticsearch
gem update # This is very dangerous. Update all existing gems
Another problem: if you install the plugin which depends on fluentd v0.14, gem installs fluentd v0.14 together even if you installed fluentd v0.12. This is unexpected result for fluentd v0.12 users.
You should specify target version with -v option.
gem install fluentd -v 0.12.43
gem install fluent-plugin-elasticsearch -v 1.9.3
/usr/sbin/td-agent-gem is also same because /usr/sbin/td-agent-gem uses gem command internally.
For example, if you have following Gemfile at /etc/fluent/Gemfile:
You can pass this Gemfile to Fluentd via the --gemfile option.
When specifying the --gemfile option, Fluentd will try to install the listed gems using Bundler. Fluentd will only load listed gems separated from shared gems, and will also prevent unexpected plugin updates.
In addition, if you update Fluentd's Ruby version, Bundler will re-install the listed gems for the new Ruby version. This allows you to avoid the C extension API compatibility problem.
A Ruby application manages gem dependencies using Gemfile and . Fluentd's --gemfile option takes the same approach, and is useful for managing plugin versions separated from shared gems.
If this article is incorrect or outdated, or omits critical information, please . is a open source project under . All components are available under the Apache 2 License.