On Sun, Apr 29, 2012 at 9:08 AM, Salman Malik <salma...@live.com> wrote:
> Thank you both for furnishing the references and providing great > explanations. Though I had looked at some of them earlier, but now looking > at them again with your explanations in mind, makes a lot of sense. > However, there is one last question: I understand that the API client calls > are made to the REST API server running at port 9696 (by default), but what > I haven't yet understood is how these API calls are passed to/fro the > Quantum plugin. > > After some searching through the Quantum plugins' code directory, I found > a rest.py file in Ryu plugin directory that (seems to ) register handler > functions with API server that may get called when API server receives a > call, but I am not sure. Is it how the OVS plugin works as well? I mean > does all plugin register callback functions with API server (just asking > because I couldn't find anything similar in rest of plugins' code). > No, just look at the "Developing a Quantum Plugin" section of: http://wiki.openstack.org/QuantumDevelopment . Plugins get calls from the main rest API by implementing the methods in quantum/quantum_plugin_base.py dan > > Thanks, > Salman > > > ------------------------------ > Date: Sun, 29 Apr 2012 15:01:03 +0530 > Subject: Re: [Netstack] [Openstack] OpenStack Quantum plugins > From: hitesh.wade...@gmail.com > To: salma...@live.com; netst...@lists.launchpad.net; > openstack@lists.launchpad.net > CC: d...@nicira.com > > > Hi Salman, > > I think Dan explained pretty well, which will be covered all the quantum > thoughts that you have asked me. There might be some code changes are going > to happen for Folsom design feature implementation. > > Also, please have a look at here, > > 1. http://wiki.openstack.org/QuantumAPIUseCases > 2. > http://qconlondon.com/dl/qcon-london-2012/slides/SalvatoreOrlando_QuantumVirtualNetworksForOpenStackClouds.pdf > 3. > http://www.slideshare.net/danwent/quantum-folsom-summit-developer-overview > 4. > http://www.slideshare.net/danwent/openstack-quantum-intro-os-meetup-32612 > > > If you go to Salvatore's 'Inside_Quamtum' 'slide, It provides quite a > good deal of details concerning about How the nova interacts with Quantum. > > On the VIF driver side, that is a piece which runs in the nova address > space, and tells VM being spawned how their VIF should be plugged into > networks. There are VIF drivers for Quantum as well as VIF drivers for the > other network managers. VIF drivers can be both plugin and hypervisor > specific. For instance, nova/virt/<hypervisor_driver>/vif (e.g.: > nova/virt/xenapi/vif). > > For OVS and more on Network, please refer this link, > http://openvswitch.org/support/, go for > > 1. J. Pettit, J. Gross “Open vSwitch Overview,” > 2. S. Horman, “An Introduction to Open vSwitch,” > > If you want to see advance networking virtualization, refer these papers, > > 1. J. Pettit, J. Gross, B. Pfaff, M. Casado, S. Crosby, “Virtual Switching > in an Era of Advanced Edges,” > 2. B. Pfaff, J. Pettit, T. Koponen, K. Amidon, M. Casado, S. Shenker, > “Extending Networking into the Virtualization Layer,” > > I hope these will help. I am also exploring the code :) (still learner) > > Thanks, > Hitesh > > On Sun, Apr 29, 2012 at 2:41 AM, Dan Wendlandt <d...@nicira.com> wrote: > > > > On Fri, Apr 27, 2012 at 4:44 PM, Salman Malik <salma...@live.com> wrote: > > Hi Dan, > > Thanks for replying. There are few more questions: > > > > I am trying to learn the functionality of Quantum plugins used in > OpenStack. I have read through the Quantum Admin Guide and had few > basic/quick question about quantum and OVS interaction with it: > > > 1) OVS can have ports in which vNICS can be plugged, so why does it need > to use an integration bridge for connecting all VMs on the same node to a > network? > > > I'm not sure I follow what question you're asking. When OVS is running on > a host, it has one or more "bridges", and bridges have "ports". A linux > device representing the vNIC must be added as a port of a bridge being > managed by the Quantum plugin. We call this bridge the "integration > bridge". The Quantum plugin can then configure the ports and bridges > appropriately to forward traffic based on the logical model created via the > Quantum API. Can you be more precise about what you're asking here? > > In short it means that the OVS is managing the linux bridges and the linux > devices representing vNICs must be added to these bridges (Does Quantum > manager adds these devices to bridges?). > > > You have to be a bit careful here, because the linux bridge and open > vswitch are two different things (you can think of open vswitch as an > advanced version of the linux bridge). > > A driver in the Nova virt layer is actually the one who creates the linux > devices that map to vNICs. For example, libvirt creates these devices as > directed by the libvirt driver code: > https://github.com/openstack/nova/blob/master/nova/virt/libvirt/vif.py . > This code attaches the linux device to an OVS bridge as a "port". The > rest of the configuration of that port and the OVS bridge is up to the OVS > plugin agent. > > > And when you say that quantum plugin configures the ports and bridges > appropriately to forward traffic, you mean that it updates the database and > then quantum agent then assures the correct mapping of ports/network ids to > logical networks at the switch level(by adding flow entries to vSwitch? or > by adding the vNICs to right bridges, as there is one bridge per tenant's > network on compute node). Right? > > > Its not correct that there is one bridge per tenant network on the compute > node. In the case of the OVS plugin, there is a single bridge (e.g., > br-int) and different tenants are isolated based on configuration pushed > down by the agent. Really the "plugin" consists of both the code running > on the server, and (optionally) agents running on the compute nodes. Not > all plugins require agents, for example, if they have some other way of > managing the vswitch. > > > > > Thanks for the reference. I have looked at the code and just to affirm my > understanding please confirm/correct/answer the following: > Quantum manager is responsible for configuring the network for new > instances that spin up. When a tenant adds a port to his logical network > the request will be forwarded to this manager by Nova and then Manager > (using quantum client) would talk to quantum service/server (where can I > see its code?) with the REST API. According to documentation, the quantum > service is responsible for loading the plugin and passing the REST API > calls to the plugin. The plugin then updates the database. Rest of the work > is done by quantum agent. > > > See: > http://docs.openstack.org/incubation/openstack-network/admin/content/Using-dle455.html > > The workflow is actually that you create a VM with one or more vNICs, and > as part of the VM creation process, nova-network is invoked using the > allocate_for_instance RPC call. When you are running nova-network with > QuantumManager, this code uses the main Quantum REST API to create ports > for each vNIC. This is the code I pointed you to before: > https://github.com/openstack/nova/blob/master/nova/network/quantum . > Specifically, manager.py is the QuantumManager code, and > quantum_connection.py and client.py are libraries used to talk to Quantum's > REST API. > > Dan > > > Salman > > > > _______________________________________________ > Mailing list: https://launchpad.net/~openstack > Post to : openstack@lists.launchpad.net > Unsubscribe : https://launchpad.net/~openstack > More help : https://help.launchpad.net/ListHelp > > > > > -- > ~~~~~~~~~~~~~~~~~~~~~~~~~~~ > Dan Wendlandt > Nicira, Inc: www.nicira.com > twitter: danwendlandt > ~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > > > > -- > ~~~~~~~~~~~~~~~~~~~~~~~~~~~ > Dan Wendlandt > Nicira, Inc: www.nicira.com > twitter: danwendlandt > ~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > > -- > Mailing list: https://launchpad.net/~netstack > Post to : netst...@lists.launchpad.net > Unsubscribe : https://launchpad.net/~netstack > More help : https://help.launchpad.net/ListHelp > > > -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~ Dan Wendlandt Nicira, Inc: www.nicira.com twitter: danwendlandt ~~~~~~~~~~~~~~~~~~~~~~~~~~~
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