logstash - 配置 logstash 转发器时观察到错误

Question

尝试在中央服务器上配置 logstash 转发器时，出现以下错误logstash.log：

 {:timestamp=>"2015-07-07T09:05:14.742000-0500", :message=>"Unknown setting 'timestamp' for date", :level=>:error}
 {:timestamp=>"2015-07-07T09:05:14.744000-0500", :message=>"Error: Something is wrong with your configuration."}

有人可以帮忙解决这个问题吗？

这是配置文件/etc/logstash/conf.d/central.conf：：

input {
    lumberjack {
        port => 6782
        ssl_certificate => "/etc/logstash/server.crt"
        ssl_key => "/etc/logstash/server.key"
        type => "lumberjack"
    }
}
output {
    stdout { }
    elasticsearch {
        cluster => "logstash"
    }
}