In currently ceilometer architecture, the collector will only pick the message from the MQ (eg. rabbitmq etc) and save them into data store via storage abstract layer, there are 2 type of agents in ceilometer currently
- polling agents - compute and central agent daemons designed to poll OpenStack services.
- notification agent - daemon designed to listen to message queue.
as for polling agent, it will poll the data like vm io cpu etc as well as the data from datacenter like thermal fan speed etc using various technology available and send them to notification bus via pipeline
as for notification agent, it will listen on the notification bus and process the data got then send them back via pipeline the collector will collect the data sent form notification agent in the end.
Hope that helps!
Vic
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