I'm not sure if this discussion is still going on. I want to advocate using persistent storage.
We can consider power-down or power-up of some compute nodes to save power at the low usage of cloud. (As far as I know) It is not supported by OpenStack now, but I believe it will be. Let's assume that it is done by zone-manager. If zone manager keeps capabilities of the compute nodes not in a persistent storage, and zone manager dies and restarts, it will lose the information (capabilities) of the power-downed nodes. And the power-downed nodes cannot send its capabilities to the zone manager because it is down. One way to resolve this problem is that zone manager power-up those power-downed node to get their capabilities. But, using persistent storage to store capabilities of computes nodes seems to be better solution. We USC/ISI are working on heterogeneous architecture support. The issue of using persistent storage is related to our work. Currently a compute node sends the information of heterogeneous architecture (such as accelerator type, number of accelerators, etc.) as a part of its capability to zone manager. Zone manager treats it as a ephemeral data. So, the information of heterogeneous architecture is not stored to a persistent storage. So, if a zone manager dies and restarts and a compute node with extra information of heterogeneous architecture was powered-down, the zone manager may never be aware of the capability of the power-downed node. Thanks, Dong-In ---------------------- Dr. Dong-In David Kang Computer Scientist USC/ISI ----- Original Message ----- From: "Sandy Walsh" <[email protected]> To: "Jay Pipes" <[email protected]>, "Ed Leafe" <[email protected]> Cc: "Mark Washenberger" <[email protected]>, [email protected] Sent: Friday, April 15, 2011 2:24:21 PM 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
