logstash6.3.0 通过配置文件启动报错

配置文件内容：
input {

file {
path => "/var/log/messages"
type => "system"
start_position => "beginning"
}

}

output {

elasticsearch {
hosts => ["11.19.10.128:9200"]
index => "system-%{+YYYY.MM.dd}"
}
}
报错信息：
[ERROR][logstash.outputs.elasticsearch] Failed to install template.

{:message=>"Template file '' could not be found!", :class=>"ArgumentError",

:backtrace=>["/usr/local/logstash-6.3.0/vendor/bundle/jruby/2.3.0/gems/logstash-

output-elasticsearch-9.1.1-

java/lib/logstash/outputs/elasticsearch/template_manager.rb:31:in

`read_template_file'",