If I understand correctly, what really matters at least in case of Hadoop is network proximity between instances. Hence, maybe Neutron would be a better fit to provide such information. In particular, depending on virtual network configuration, having 2 instances on the same node does not guarantee that the network traffic between them will be routed within the node. Physical layout could be useful for availability-related purposes. But even then, it should be abstracted in such a way that it will not reveal details that a cloud provider will typically prefer not to expose. Maybe this can be done by Ironic -- or a separate/new project (Tuskar sounds related).
Regards, Alex From: Mike Spreitzer <mspre...@us.ibm.com> To: OpenStack Development Mailing List <openstack-dev@lists.openstack.org>, Date: 13/09/2013 08:54 AM Subject: Re: [openstack-dev] [nova] [savanna] Host information for non admin users > From: Nirmal Ranganathan <rnir...@gmail.com> > ... > Well that's left upto the specific block placement policies in hdfs, > all we are providing with the topology information is a hint on > node/rack placement. Oh, you are looking at the placement of HDFS blocks within the fixed storage volumes, not choosing where to put the storage volumes. In that case I understand and agree that simply providing identifiers from the infrastructure to the middleware (HDFS) will suffice. Coincidentally my group is working on this very example right now in our own environment. We have a holistic scheduler that is given a whole template to place, and it returns placement information. We imagine, as does Hadoop, a general hierarchy in the physical layout, and the holistic scheduler returns, for each VM, the path from the root to the VM's host. Regards, Mike_______________________________________________ OpenStack-dev mailing list OpenStack-dev@lists.openstack.org http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
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