Jagane, good question. There can be many schedulers running within a Zone (each with their own ZoneManager). They service scheduler requests round-robin thanks the AMQP. We can have them not listen for events until, let's say, 30 seconds has elapsed (the update interval).
Thanks for the note about hadoop ... didn't know that! -S ________________________________________ From: Jagane Sundar [[email protected]] Sent: Friday, April 15, 2011 3:39 PM To: Sandy Walsh; Jay Pipes; Ed Leafe Cc: Mark Washenberger; [email protected] Subject: RE: [Openstack] distributed and heterogeneous schedulers What happens if a ZoneManager process dies? When the ZoneManager restarts, the compute nodes will send their attributes to the newly restarted ZoneManager and the in-memory list of attributes will be reconstructed, right? The only downside to this approach is the (probably short) time that it takes for the restarted ZoneManager to reconstruct its in-memory db of host attributes. As an unrelated side note, the folks over in Hadoop land use this sort of 'in-memory data-structures fed by heartbeats' approach with much success. - Jagane ________________________________________ From: [email protected] [[email protected]] On Behalf Of Sandy Walsh [[email protected]] Sent: Friday, April 15, 2011 2:24 PM To: Jay Pipes; Ed Leafe Cc: Mark Washenberger; [email protected] Subject: Re: [Openstack] distributed and heterogeneous schedulers Each update from the services are atomic updates ... fully self contained. Why does this need to be in a persistent store? -S ________________________________________ From: Jay Pipes [[email protected]] > you still need a persistent data store for attributes of the host. Just > because you > store a cached in-memory copy of instance attributes, doesn't mean you > don't need a persistent data store. You still need a persistent data > store regardless of whether it's a database table, a FLAG value, or > /proc/cpuinfo. _______________________________________________ Mailing list: https://launchpad.net/~openstack Post to : [email protected] Unsubscribe : https://launchpad.net/~openstack More help : https://help.launchpad.net/ListHelp _______________________________________________ Mailing list: https://launchpad.net/~openstack Post to : [email protected] Unsubscribe : https://launchpad.net/~openstack More help : https://help.launchpad.net/ListHelp
