Thanks, I understand the Nova scheduler part. One of the gaps there is related to the blueprint we have are working on [1]. I was wondering regarding the role of Ironic, and the exact interaction between the user, Nova and Ironic. In particular, initially I thought that Ironic is going to have its own scheduler, resolving some of the issues and complexity within Nova (which could focus on VM management, maybe even getting rid of hosts versus nodes, etc). But it seems that Ironic aims to stay at the level of virt driver API.. It is a bit unclear to me what is the desired architecture going forward - e.g., if the idea is to standardize virt driver APIs but keep the scheduling centralized, maybe we should take the rest of virt drivers into separate projects as well, and extend Nova to schedule beyond just compute (if it is already doing so for virt + bare-metal). Alternatively, each of them could have its own scheduler (like the approach we took when splitting out cinder, for example) - and then someone on top (e.g., Heat) would need to do the cross-project logic. Taking different architectural approaches in different cases confuses me a bit.
Thanks, Alex [1] https://blueprints.launchpad.net/nova/+spec/multiple-scheduler-drivers From: Devananda van der Veen <devananda....@gmail.com> To: "OpenStack Development Mailing List (not for usage questions)" <openstack-dev@lists.openstack.org>, Date: 13/11/2013 10:29 PM Subject: Re: [openstack-dev] [Nova] [Ironic] [TripleO] scheduling flow with Ironic? On Wed, Nov 13, 2013 at 8:02 AM, Alex Glikson <glik...@il.ibm.com> wrote: Hi, Is there a documentation somewhere on the scheduling flow with Ironic? The reason I am asking is because we would like to get virtualized and bare-metal workloads running in the same cloud (ideally with the ability to repurpose physical machines between bare-metal workloads and virtualized workloads), and would like to better understand where the gaps are (and potentially help bridging them). Hi Alex, Baremetal uses an alternative scheduler, nova.scheduler.baremetal_host_manager.BaremetalHostManager, so giving that a read may be helpful. It searches the available list of baremetal nodes for one that matches the CPU, RAM, and disk capacity of the requested flavor, and compares the node's extra_specs:cpu_arch to that of the requested image, then consumes 100% of that node's available resources. Otherwise, I believe the scheduling flow is basically the same: http request to n-api, rpc passes to n-scheduler, which selects a node, and calls to n-conductor & n-cpu to do the work of spawn()ing it. As far as the gaps in running both baremetal and virtual -- I have been told by several folks that it's possible to run both baremetal and virtual hypervisors in the same cloud by using separate regions, or separate host-aggregates, for the simple reason that these require distinct nova-scheduler processes. A single scheduler, today, can't serve both. I haven't seen any docs on how to do this, though. As for moving a workload between them, the TripleO team has discussed this and, afaik, decided to hold off working on it for now. It would be better for them to fill in the details here -- my memory may be wrong, or things may have changed. Cheers, Devananda _______________________________________________ OpenStack-dev mailing list OpenStack-dev@lists.openstack.org http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
_______________________________________________ OpenStack-dev mailing list OpenStack-dev@lists.openstack.org http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
