On Mon, Jul 25, 2011 at 4:58 AM, Ishimoto, Ryu <r...@midokura.jp> wrote:
> Hi Sumit, > > Comments inline > > Thanks Dan for your detailed response. My question was indeed based on the >> understanding that the current nova network managers (in the network >> service) do perform some L3/DHCP/VPN configurations apart from L2 >> configuration. As of today’s implementation in the network-refactoring-l2 >> branch, one would need to run the nova-network service configured with >> either one of Flat/DHCP/VLANManagers even when running Quantum as a separate >> service, right? If that is the case, how does one correlate an entry in the >> network table in the nova database, with a network created in Quantum? (I do >> realize that one could write a different network manager within nova, but my >> question is more in the context of what is available today.) >> > > Because Nova still relies on certain features provided by the Nova network > managers(like IP management), you have to run one of Flat/DHCP/VlanManagers > as a network service, or define your own manager. I understand the > confusion about the correlation between Networks in Nova and Quantum, and I > don't think this topic has been adequately discussed, so might as well start > here :-) > > The confusion comes from the fact that Nova Network includes both L3 and L2 > information. As far as I understand it, when integrating with Quantum, the > L2 data is ignored. However, since currently the IP management is still > being done by the network managers, for Quantum to work with Nova L3 > networking, these Network records must still exist to act as subnets in > which the VIFs get their IP addresses from. This means that Networks in > Quantum and Nova are managed separately, and mean different things. Dan, > please comment if you were thinking something different. > That's right. Essentially, if you are using one of the existing nova NetworkManagers, you need to make sure the L2 Quantum networks you "match" the IP subnets used by nova (e.g., if two VMs are on the same L2 network, they are on the same subnet). > > I am guessing that the current approach is to use the Flat/DHCP/VLANManger >> to configure the L3/DHCP/VPN artifacts, and to use Quantum to configure the >> L2 network (in cases where it’s not a Linux bridge). >> > > The network host, when you run one of the existing Nova network managers, > still uses Linux bridge and VLAN to set up L2 connectivity. This should be > eventually refactored, but for now, one could extend the NetworkManager > class to setup L2 networking on the network host to match that of the VIF > plugins. > I hacked on nova this weekend to introduce vif-plugging into the network-host code as well. Still need to do some more work before merge-propping it though. > > ** ** >> >> But, I did also want to ask, as to what is the thinking around nova >> communicating with Quantum (if required). You have rightly pointed out >> “reporting the interface binding” as one of the cases when this might need >> to be done. Another case wherein I think this might be relevant is if the >> VIF driver (within nova virt layer) needs some information about the network >> from Quantum. There would need to be a communication channel between the VIF >> driver and Quantum to achieve this. I believe your suggestion is that in any >> of these cases, the Quantum client library can be used to communicate with >> the Quantum API (either core or extensions). >> > > I think we can do either: > > - Have the VIF driver directly communicate with Quantum to get the > relevant data at the time of 'plugging' in the VIF in the virt layer. > - At the time in which the compute manager gets network information > from the network manager(allocate_for_instance), have the extended > Quantum-aware network manager get the relevant data from Quantum, and > return > it to the compute manager, which in turn passes this data down to the virt > layer(network_info dictionary). > > The first one is easier to implement, but you will end up with a dependency > of a particular VIF type(802.1Qbh) to a Quantum service. > Yes, currently the first approach is probably best. The API that your 802.1qbh vif-plugging code hits can actually just be an extension to your Quantum 802.1qbh plugin. > > **** >> >> ** ** >> >> As for the part on APIs which was not clear in my email, yes I was >> referring to the “nova-api (i.e. the OpenStack API) will expose >> interface-ids as an API extension”, as you point out. I believe, the >> extension referred to here is on the nova API side (and not on the Quantum >> side as my email seemed to suggest), right? >> > > Right, the exposure of interface IDs will be done through Nova's OpenStack > API extension. I will get this extension in for the next milestone. > Awesome Ryu :) > > Hope that helped! > > Thanks, > Ryu > > **** >> >> ** ** >> >> Thanks,**** >> >> ~Sumit.**** >> >> ** ** >> >> *From:* Dan Wendlandt [mailto:d...@nicira.com] >> *Sent:* Sunday, July 24, 2011 10:46 PM >> *To:* Sumit Naiksatam (snaiksat) >> *Cc:* Ishimoto, Ryu; netstack@lists.launchpad.net >> *Subject:* Re: "network-refactoring-l2" branch, and Quantum**** >> >> ** ** >> >> Hi Sumit,**** >> >> ** ** >> >> Very good questions. I'll give you my take inline, and Ryu should jump in >> as well :) **** >> >> ** ** >> >> Dan**** >> >> On Sun, Jul 24, 2011 at 12:50 PM, Sumit Naiksatam (snaiksat) < >> snaik...@cisco.com> wrote:**** >> >> Hi Ryu, Dan, and others involved, >> >> I had some questions regarding how the code base in the >> "network-refactoring-l2" branch currently works (or is supposed to) with >> Quantum.**** >> >> ** ** >> >> The network-refactoring-l2 branch itself doesn't actually interact with >> Quantum. It is really just a first step to providing more flexibility >> within nova for how VM interfaces are created and plugged into a "switch". >> This will be very helpful for many people using Quantum, as the existing >> nova code was hard-coded to use the Linux bridge. **** >> >> **** >> >> >> As I understand, eventually we want to get to a point where one should >> be able to run the Quantum service instead of the nova-network service.** >> ** >> >> ** ** >> >> I actually don't think that's necessarily true. The existing nova-network >> service does many things beyond L2 networking, namely: **** >> >> ** ** >> >> - IP address management (melange project is targeting providing an >> improved version of this)**** >> >> - Network Node capabilities, including DHCP, L3 gateway, VPN, metadata >> server, floating IP forwarding, etc (such functionality may grow to be their >> own independent services, or an addon to Quantum in the future). **** >> >> - Network orchestration, in the sense that it automatically attaches VIFs >> to networks based on config (vlan vs. flat manager) and project assignment >> (donabe aims to become the primary mechanism for this type of orchestration, >> though some simple behavior equivalent to the existing flat/flatdhcp/vlan >> models may make sense to stay in nova for a while). **** >> >> ** ** >> >> There are some obvious next steps for D4:**** >> >> - Ryu will continue the work to merge his work that makes sure that other >> nova services retrieve network info via the API (not the DB). This is a >> critical step. **** >> >> - We'll expose interface-ids via the nova API (likely as an extension)*** >> * >> >> - Troy's team will continue integrating the melange code with nova. **** >> >> - We'll probably create an alternate NetworkManager class (and >> corresponding manager utility) that uses melange for IPAM, quantum for L2 >> networks, and supports several different orchestration options. **** >> >> **** >> >> However, we are not there yet. Currently one still needs to run the >> nova-network service in order to be able create the network on the nova >> side of things. If this understanding is correct, here are few thoughts >> and questions - >> >> (1) How are you reconciling the network created within nova, with that >> created in Quantum?**** >> >> ** ** >> >> Current nova networks are a bit tricky, as they represent both L2 networks >> and IP subnets. A new network manager class + utility will give us the >> flexibility to handle this however we want. **** >> >> **** >> >> >> (2) The blueprint for this branch indicates that OpenStack APIs will be >> implemented as extension APIs in Quantum. Do we have any documentation >> on this API? (Also, I did not find any implementation in the Quantum >> trunk, I am guessing we haven't done that yet, right?)**** >> >> ** ** >> >> I'm not sure I follow what you're saying here. I suspect you are >> referring to the fact that nova-api (i.e. the OpenStack API) will expose >> interface-ids as an API extension? Those changes have not gone into nova >> yet, but are on the list I mentioned above. **** >> >> ** ** >> >> **** >> >> >> (3) There was earlier some talk about nova using an "administrative API" >> to communicate with Quantum. Is that still the plan? In general, what is >> the thinking around how nova would communicate with Quantum?**** >> >> ** ** >> >> There are possible uses that I have mentioned for such an admin API:**** >> >> ** ** >> >> - Reporting "interface bindings" from nova to a quantum plugin. Right >> now, since the nature of the binding is specific to the nova vif-plugin >> itself, we're leaving the communication of this binding info up to the >> plugin itself, so you're free to do whatever you want (your quantum plugin >> can expose additional APIs if needed). If there is code to share here, >> we'll probably just do it by sharing a code library (I suspect the new >> network manager we build will also require the quantum client library, which >> I would see an a nova dependency if using quantum). **** >> >> - Communicating permission to plug a vif. There have been a couple emails >> back and forth about this on the list. I am hoping we can use keystone for >> this, which in case no direct nova/quantum communication is needed. >> Otherwise, we'll probably create an admin API for this. **** >> >> ** ** >> >> **** >> >> >> Thanks, >> ~Sumit.**** >> >> >> >> >> -- >> ~~~~~~~~~~~~~~~~~~~~~~~~~~~ >> Dan Wendlandt >> Nicira Networks, Inc. >> www.nicira.com | www.openvswitch.org >> Sr. Product Manager >> cell: 650-906-2650 >> ~~~~~~~~~~~~~~~~~~~~~~~~~~~**** >> > > -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~ Dan Wendlandt Nicira Networks, Inc. www.nicira.com | www.openvswitch.org Sr. Product Manager cell: 650-906-2650 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
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