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heartbeats for compute nodes?

asked 2011-06-09 20:18:58 -0500

fred-yang gravatar image

nova-compute creates "nova-compute" into CC DB.service table and new entry into table. nova-compute then periodically update and report_count fields.

Any way for CC to know a compute node is restarted or the nova-compute service is restarted? any event notification method than continually polling nova DB in monitoring update_at & report_count?

Thanks -Fred

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answered 2011-06-14 11:00:43 -0500

np Fred, happy to help ... don't hesitate to ping me if you run into issues.

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answered 2011-07-11 21:25:10 -0500

fred-yang gravatar image


Continue ZoneManager.service_states[] locking question on this same thread.

ZoneManager.update_service_capabilities() is updating service_states per compute_node periodic_tasks, where JsonFilter.filter_hosts() is also looping through service_states[] to filter each hosts. There is no data locking while accessing service_states[] from both controls, is it implicitly serialized through AMQP by nova-scheduler executing zoneManger and filter_hosts. Am I read it correct?!

nova-scheduler also schedules periodically through greenthread. If we derive ping() from SchedulerManager() to update service_states[] periodically on the same scheduler node, any data locking needed or what will be the better locking method?

Thanks, -Fred

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answered 2011-07-11 22:31:06 -0500

Hey Fred,

Correct, it's my understanding that since we're using Eventlet (a Reactor pattern), we shouldn't run into concurrency issues since the service is essentially single threaded. GreenPool is an Eventlet-aware mechanism, so it should be safe too.

Downside is it won't take advantage of multi-core/processors, but we can fire up more than one service.


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answered 2011-07-12 16:10:46 -0500

fred-yang gravatar image

GreenThread is a cooperative yield model according to Eventlet doc, so it should be safe. Thanks for sharing the light.

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Asked: 2011-06-09 20:18:58 -0500

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Last updated: Jul 12 '11