What do MBean parameters mean in collectd

collectdjmxkafkamonitoring

I'm using JMX to monitor an Apache Kafka cluster with collectd's GenericJMX plugin. However, I'm not sure what some of the MBean parameters mean.

Particularly, I have one metric called kafka.server:type=BrokerTopicMetrics,name=MessagesInPerSec, showing the number of messages per second received by one machine. This is my configuration file for this MBean:

<MBean "kafka-all-messages">
  ObjectName "kafka.server:type=BrokerTopicMetrics,name=MessagesInPerSec"
  InstancePrefix "all"
  <Value>
    InstancePrefix "kafka-messages-in"
    Type "counter"
    Table false
    Attribute "MeanRate"
  </Value>
</MBean>

I don't know which Type is the correct one for this measurement, such as gauge, counter or another one. I've tried reading this documentation on collectd by couldn't really understand where I should apply each measurement type.

Could someone explain me it?

Best Answer

This looks like a gauge, by virtue of being a 'Per' value -- Kafka is already normalizing this into a particular time frame. If the name was just 'MessagesIn' I'd expect it to be a counter -- a number that continually increases as messages come in.

In other words, if the bean returns the 'right now' of something, it is a gauge. If it returns the 'total so far' of something, it is a counter. MessagesInPerSec is a 'current state' value so is a gauge.

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