Open Stack

One way would be to achieve this via "Availabilty zones". Just create 2
host aggregates (and with it a such a zone) and add a hypervisor to each
of them (host aggreate to availability zone is 1:1 mapping)

The instance launch dialog allows you to select the zone.

Hope this helps


On Fr, 2015-06-26 at 12:38 +0000, YANG LI wrote:
> Thanks, James for the explanation. it make more sense now. it is
> possible that a instances on same tenant network reside on different
> compute nodes right? how do I tell which compute node a instance is
> on?  
> 
> 
> Thanks,
> Yang
> 
> > On Jun 24, 2015, at 10:27 AM, James Denton
> > <james.denton at rackspace.com> wrote:
> > 
> > Hello.
> > 
> > > all three nodes will have eth0 on management/api network. since I
> > > am using ml2 plugin with vlan for tenant network, I think all
> > > compute node should have eth1 as the second nic on provider
> > > network. Is this correct?  I understand provider network is for
> > > instance to get external access  to internet, but how is instance
> > > live on compute1  communicate with instance live on compute2? are
> > > they also go through provider network?
> > 
> > In short, yes. If you’re connecting instances to vlan “provider”
> > networks, traffic between instances on different compute nodes will
> > traverse the “provider bridge”, get tagged out eth1, and hit the
> > physical switching fabric. Your external gateway device could also
> > sit in that vlan, and the default route on the instance would direct
> > external traffic to that device.
> > 
> > In reality, every network has ‘provider’ attributes that describe
> > the network type, segmentation id, and bridge interface (for
> > vlan/flat only). So tenant networks that leverage vlans would have
> > provider attributes set by Neutron automatically based on the
> > configuration set in the ML2 config file. If you use Neutron routers
> > that connect to both ‘tenant’ vlan-based networks and external
> > ‘provider’ networks, all of that traffic could traverse the same
> > provider bridge on the controller/network node, but would be tagged
> > accordingly based on the network (ie. vlan 100 for external network,
> > vlan 200 for tenant network).
> > 
> > Hope that’s not too confusing!
> > 
> > James
> > 
> > > On Jun 24, 2015, at 8:54 AM, YANG LI <yangli at clemson.edu> wrote:
> > > 
> > > I am working on install openstack from scratch, but get confused
> > > with network part. I want to have one controller node, two compute
> > > nodes.
> > > 
> > > the controller node will only handle following services:
> > > glance-api
> > > glance-registry
> > > keystone
> > > nova-api
> > > nova-cert
> > > nova-conductor
> > > nova-consoleauth
> > > nova-novncproxy
> > > nova-scheduler
> > > qpid
> > > mysql
> > > neutron-server
> > > 
> > > compute nodes will have following services:
> > > neutron-dhcp-agent
> > > neutron-l3-agent
> > > neutron-metadata-agent
> > > neutron-openvswitch-agent
> > > neutron-ovs-cleanup
> > > openvswtich
> > > nova-compute
> > > 
> > > all three nodes will have eth0 on management/api network. since I
> > > am using ml2 plugin with vlan for tenant network, I think all
> > > compute node should have eth1 as the second nic on provider
> > > network. Is this correct?  I understand provider network is for
> > > instance to get external access  to internet, but how is instance
> > > live on compute1  communicate with instance live on compute2? are
> > > they also go through provider network?
> > > _______________________________________________
> > > Mailing list:
> > > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack
> > > Post to     : openstack at lists.openstack.org
> > > Unsubscribe :
> > > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack
> > 
> > 
> 
> 
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-- 
Andreas
(IRC: scheuran)