----- Original Message ----- > From: "Sangeeta Singh" <sin...@yahoo-inc.com> > To: "OpenStack Development Mailing List (not for usage questions)" > <openstack-dev@lists.openstack.org> > Sent: Wednesday, March 26, 2014 6:54:18 PM > Subject: Re: [openstack-dev] [nova][scheduler] Availability Zones and Host > aggregates.. > > > > On 3/26/14, 10:17 AM, "Khanh-Toan Tran" <khanh-toan.t...@cloudwatt.com> > wrote: > > > > > > >----- Original Message ----- > >> From: "Sangeeta Singh" <sin...@yahoo-inc.com> > >> To: "OpenStack Development Mailing List (not for usage questions)" > >><openstack-dev@lists.openstack.org> > >> Sent: Tuesday, March 25, 2014 9:50:00 PM > >> Subject: [openstack-dev] [nova][scheduler] Availability Zones and Host > >>aggregates.. > >> > >> Hi, > >> > >> The availability Zones filter states that theoretically a compute node > >>can be > >> part of multiple availability zones. I have a requirement where I need > >>to > >> make a compute node part to 2 AZ. When I try to create a host aggregates > >> with AZ I can not add the node in two host aggregates that have AZ > >>defined. > >> However if I create a host aggregate without associating an AZ then I > >>can > >> add the compute nodes to it. After doing that I can update the > >> host-aggregate an associate an AZ. This looks like a bug. > >> > >> I can see the compute node to be listed in the 2 AZ with the > >> availability-zone-list command. > >> > > > >Yes it appears a bug to me (apparently the AZ metadata indertion is > >considered as a normal metadata so no check is done), and so does the > >message in the AvailabilityZoneFilter. I don't know why you need a > >compute node that belongs to 2 different availability-zones. Maybe I'm > >wrong but for me it's logical that availability-zones do not share the > >same compute nodes. The "availability-zones" have the role of partition > >your compute nodes into "zones" that are physically separated (in large > >term it would require separation of physical servers, networking > >equipments, power sources, etc). So that when user deploys 2 VMs in 2 > >different zones, he knows that these VMs do not fall into a same host and > >if some zone falls, the others continue working, thus the client will not > >lose all of his VMs. It's smaller than Regions which ensure total > >separation at the cost of low-layer connectivity and central management > >(e.g. scheduling per region). > > > >See: http://www.linuxjournal.com/content/introduction-openstack > > > >The former purpose of regouping hosts with the same characteristics is > >ensured by host-aggregates. > > > >> The problem that I have is that I can still not boot a VM on the > >>compute node > >> when I do not specify the AZ in the command though I have set the > >>default > >> availability zone and the default schedule zone in nova.conf. > >> > >> I get the error ³ERROR: The requested availability zone is not > >>available² > >> > >> What I am trying to achieve is have two AZ that the user can select > >>during > >> the boot but then have a default AZ which has the HV from both AZ1 AND > >>AZ2 > >> so that when the user does not specify any AZ in the boot command I > >>scatter > >> my VM on both the AZ in a balanced way. > >> > > > >I do not understand your goal. When you create two availability-zones and > >put ALL of your compute nodes into these AZs, then if you don't specifies > >the AZ in your request, then AZFilter will automatically accept all hosts. > >The defaut weigher (RalWeigher) will then distribute the workload fairely > >among these nodes regardless of AZ it belongs to. Maybe it is what you > >want? > > With Havana that does not happen as there is a concept of > default_scheduler_zone which is none if not specified and when we specify > one can only specify a since AZ whereas in my case I basically want the 2 > AZ that I create both to be considered default zones if nothing is > specified.
If you look into the code of the AvailabilityFilter, you'll see that the filter automatically accepts host if there is NO availability-zone in the request, which is the case when user does not specify AZ. This is exactly what I see in my Openstack platform (Hanava stable). FYI, I didn't set up a default AZ in config. So whenever I creates several VMs without specifying an AZ, the scheduler spreads the VMs into all hosts regardless of their AZ. What I think lacking is that user can not select a set of AZs instead of one or none right now. > > > >> Any pointers. > >> > >> Thanks, > >> Sangeeta > >> > >> _______________________________________________ > >> 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 > > > _______________________________________________ > 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
