You can absolutely have instances in the same network span different compute nodes. As an admin, you can run ‘nova show <instanceid>’ and see the host in the output:
root@controller01:~# nova show 7bb18175-87da-4d1f-8dca-2ef07fee9d21 | grep host | OS-EXT-SRV-ATTR:host | compute02 | That info is not available to non-admin users by default. James > On Jun 26, 2015, at 7:38 AM, YANG LI <yan...@clemson.edu> wrote: > > Thanks, James for the explanation. it make more sense now. <http://now.it/> > 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.den...@rackspace.com >> <mailto:james.den...@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 <yan...@clemson.edu >>> <mailto:yan...@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 >>> <http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack> >>> Post to : openstack@lists.openstack.org >>> <mailto:openstack@lists.openstack.org> >>> Unsubscribe : http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack >>> <http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack> >> >
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