执行./logstash -f /etc/logstash/pipelines.yml ,输出中提示"Couldn't find any input plugin named 'log4j',这个log4j是需要单独安装的插件吗,这个如何安装
[2018-05-29T17:27:56,748][ERROR][logstash.agent ] Failed to execute action {:action=>LogStash::PipelineAction::Create/pipeline_id:main, :exception=>"LogStash::PluginLoadingError", :message=>"Couldn't find any input plugin named 'log4j'. Are you sure this is correct? Trying to load the log4j input plug