[Kimchi-devel] RFC: Templates API changes for 'networks' attribute

Daniel Henrique Barboza dhbarboza82 at gmail.com
Mon Aug 15 14:10:58 UTC 2016


Hi Chandra,

Thanks for this detailed summary. I have a better idea of the problem 
and the proposal now.

First a generic comment: Kimchi also supports a libvirt network called 
passthrough.

Second, I think we may have a different approach here. I am seeing that 
the 'network'
key isn't required in those APIs, they are optional. If we're going into 
the trouble of changing
an existing API why not add a new optional parameter 'interface' to 
attach the interface
into the VM without relying on libvirt networks?

This way you have a clearer functionality difference in the API and it 
will be easier to code
because you will not mess with existing code that relies on libvirt 
networks. And, in my opinion,
it can be used not only by s390x but for everyone that, for any given 
reason, might want
to attach directly an interface to the VM instead of relying in a 
libvirt network.

Most of the work will be in adapting the existing UI to provide both 
options (with or without
libvirt network) and show the user that they are mutually exclusive.

Is the idea feasible? Making the 2 approaches coexist?


Daniel

On 08/12/2016 10:45 AM, Chandra Shekhar Reddy Potula wrote:
>
> Hi All,
>
> Let me put the detailed summary !!!
>
> In case of platform s390x, any of the libvirt networks are not 
> supported. The only way is attaching the physical interface macvtap or 
> attaching ovs bridge directly to the guest at this point of time.
>
> *Expectation of the RFC is to attach macvtap and ovs directly to the 
> guest with out libvirt API calls.*
>
> Example domain xml translations of macvtap and ovs (with out any 
> libvirt calls):
>
> *OVS: *
> <interface type="bridge">
>   <source bridge="vswitch0"/>
>   <virtualport type="openvswitch"/>
>   <model type="virtio"/>
> </interface>
>
> *Macvtap:*
> macvtap with bridge mode:
> <interface type="direct">
>   <source dev="eth0" mode="bridge"/>
>   <model type="virtio"/>
> </interface>
>
>  macvtap with vepa mode:
> <interface type="direct">
>   <source dev="bond0" mode="vepa"/>
>   <model type="virtio"/>
> </interface>
>
> In order to achieve above functionality on s390x, recommend the 
> following proposal to the templates and guest networking API’s 
> (/templates and /vms/:name/ifaces):
> **Note : the same functionality can also exploited on other platforms 
> too like on x86/ppc etc…*
>
> *1. Templates*
> A. Current : template.conf contains the following details for networks :
>
> [main]
>
> 
# List of networks separated by comma
# Represents the virtual 
> network interfaces to be assigned to guest
#networks = default,
>
> Proposal : is to have dictionary based network details in the conf 
> file similar to storage pools.
>
> [interfaces]

>
> # List of interfaces in the form of dictionary 
# Supports attaching 
> virtual networks, macvtap and ovs bridge to the guest.
> # type can be of ‘network’ | ‘macvtap’ | ‘ovs’
> # source can be list network or interface or resource bridge name. 
> Comma separated values allowed if they are of same type.
> # mode required only for macvtap. mode can be either bridge or vepa
>
> [interfaces.0]
> #type=network
> #source=default
> #mode=NA
>
> For example to understand other possible types:
> [interfaces.1]
> #type=macvtap
> #source=eth0, eth1
> #mode=bridge or vepa
>
> [interfaces.2]
> #type=ovs
> #source=ovsswitch1
> #mode=NA
>
> B. API changes for the templates
>
> Current: network attributes for create/update of template
> networks (optional): list of networks will be assigned to the new VM.
>
> Proposal:
> networks (optional): list of dictionary of networks will be assigned 
> to the new VM.
>                                 type : ‘network’ | ‘macvtap’ | ‘ovs’. 
> By specifying macvtap or ovs these interface will be attaching to 
> guest directly.
>                                 source : network or interface or 
> resource bridge name
>                                 mode(optional) : kimchi supports 
> ’bridge’ or ‘vepa’. required only if type=‘macvtap’
>
>
> *2. Virtual Machine Network Interfaces*
> *URI: */plugins/kimchi/vms/:name/ifaces
>
> Current:
> POST: attach a network interface to VM
> * model (optional): model of emulated network interface card. It can 
> be one of these models: ne2k_pci, i82551, i82557b, i82559er, rtl8139, 
> e1000, pcnet and virtio. When model is missing, libvirt will set 
> 'rtl8139' as default value.
> * network (optional): the name of resource network, it is required 
> when the interface type is network.
> * type: The type of VM network interface that libvirt supports. Now 
> kimchi just supports 'network' type.
>
> Proposal:
> POST: attach a network interface to VM
> * model (optional): model of emulated network interface card. It can 
> be one of these models: ne2k_pci, i82551, i82557b, i82559er, rtl8139, 
> e1000, pcnet and virtio. When model is missing, libvirt will set 
> 'rtl8139' as default value.
> * source : the name of resource network or interface or resource 
> bridge name
> * type: kimchi supports 'network'  | ‘macvtap’ | ‘ovs’ type.
> * mode : kimchi supports ’bridge’ or ‘vepa’. required only if 
> type=‘macvtap’
>
> *3. Virtual Machine Network Interface**
> **URI:* /plugins/kimchi/vms/:name/ifaces/:mac
>
> Current:
> GET: Retrieve the full description of the VM network interface
> * bridge (optional): the name of resource bridge, only be available 
> when the interface type is bridge.
> * mac: Media Access Control Address of the VM interface.
> * ips: A list of IP addresses associated with this MAC.
> * model (optional): model of emulated network interface card. It will 
> be one of these models: ne2k_pci, i82551, i82557b, i82559er, rtl8139, 
> e1000, pcnet and virtio.
> * network (optional): the name of resource network, only be available 
> when the interface type is network.
> * type: The type of VM network interface that libvirt supports. It 
> will be one of these types: 'network', 'bridge', 'user','ethernet', 
> 'direct', 'hostdev', 'mcast', 'server' and 'client'.
>
> Proposal:
> GET: Retrieve the full description of the VM network interface
> * mac: Media Access Control Address of the VM interface.
> * ips: A list of IP addresses associated with this MAC.
> * model (optional): model of emulated network interface card. It will 
> be one of these models: ne2k_pci, i82551, i82557b, i82559er, rtl8139, 
> e1000, pcnet and virtio.
> * source: the name of resource network or resource bridge or interface
> * type: It will be one of these types: 'network', ‘macvtap’, ‘ovs’, 
> ’bridge', 'user','ethernet', 'direct', 'hostdev', 'mcast', 'server' 
> and 'client'.
> * mode : kimchi supports ’bridge’ or ‘vepa’. required only if 
> type=‘macvtap’
>
> Please feel free to suggest any other better ways of doing !!!
>
> Regards
> Chandra
> On 8/11/16 4:46 PM, Suresh Babu Angadi wrote:
>>
>>
>> On 08/10/2016 11:56 PM, Daniel Henrique Barboza wrote:
>>> A lot of changes to be made.
>>>
>>> The changes in Ginger -> Gingerbase regarding OVS bridges is the 
>>> simplest
>>> to do. Gingerbase already has some OVS legacy functions from before 
>>> Ginger
>>> developed the OVS bridges backend in the module netinfo.py. We can 
>>> see if
>>> there's something there to list OVS interfaces (can't recall now) 
>>> and, if not, we
>>> can add it.
>>>
>>> The remaining Kimchi changes will need to either do in small chunks, 
>>> avoiding
>>> changing the working code we have today, or all at once with UI 
>>> changes included
>>> to avoid breaking the existing UI with the API change. I'll leave it 
>>> up to you which
>>> approach to go, as long as we don't break the existing network 
>>> support in Kimchi
>>> in the process.
>> Agree.
>>>
>>> Assuming that all this precautions are made, I approve this RFC. 
>>> However, note that
>>> this is *my* opinion. I am not the official maintainer of this 
>>> plug-in and it would
>>> be unwise to rely solely on it. It is safer to wait for Aline's 
>>> opinion in this
>>> RFC before taking any step toward the implementation.
>> To support s390x architecture which doesn't support libvirt virtual 
>> networks as of today,, its necessary to allow attaching physical 
>> interface to guest. Hence would start implementing, however any 
>> changes/suggestions can be accommodated.
>>>
>>>
>>> Daniel
>>>
>>> On 08/10/2016 05:46 AM, Archana Singh wrote:
>>>>
>>>> On 08/10/2016 12:23 PM, Suresh Babu Angadi wrote:
>>>>>
>>>>>
>>>>> On 08/10/2016 12:24 AM, Daniel Henrique Barboza wrote:
>>>>>> I am worried not only by the API.json changes but also in the
>>>>>> potential backend changes required. Do you have any prediction of
>>>>>> how far these changes might go?
>>>>> from backend, it would remain same for virtual network. For 
>>>>> macvtap, validation of interface would be okay since interfaces 
>>>>> listing is moved to gingerbase and kimchi is using it for networks 
>>>>> hence same code can be utilized. For openvswitch, ginger code will 
>>>>> have to be moved to gingerbase to enable kimchi to list host ovs 
>>>>> interfaces.
>>>> On high level I guess below needs to be done, and both point below 
>>>> are independent of each-other.
>>>> 1) Listing of networks based on selected type. (This will mostly 
>>>> use to show list in UI, based on type).
>>>> 2) Once network is selected/provided, an REST API call which will 
>>>> land to control and model. From control point of view it will be 
>>>> addition of parameters. And from model point of view, we need to 
>>>> add if and else to check type.
>>>> And for virtual type, existing code implementation should work. And 
>>>> for other two type, we need add code for addition of these options 
>>>> in template params. And also code to generate corresponding xml 
>>>> based on type.
>>>> It will be mostly on template/guest edit/create code and network 
>>>> add/remove from guest/template.
>>>>
>>>> May be validation of network(s) to check if network(s) exist( for 
>>>> type macvtap and ovs) or not can be done as improvement to feature.
>>>>
>>>>>>
>>>>>> On 08/09/2016 06:12 AM, Suresh Babu Angadi wrote:
>>>>>>> Hi All,
>>>>>>> To support, attaching a physical interface to guest as macvtap 
>>>>>>> or attaching ovs bridge to guest without creating libvirt 
>>>>>>> network, I propose following changes to 'networks' attribute of 
>>>>>>> templates josn.
>>>>>>>
>>>>>>> current implementation:
>>>>>>> 'networks' attribute expects list of virtual network names
>>>>>>>
>>>>>>> changes:
>>>>>>> 'networks': list of dictionary
>>>>>>>                 type: can be direct, network or bridge
>> Small change in type, to be explicit, its good to have type as 
>> macvtap(instead of direct), ovs(instead of bridge) and 
>> virtualnetwork(instead of network).
>>>>>>>                 interface: name of physical 
>>>>>>> interface(type=direct) or ovs (type=bridge) or virtual 
>>>>>>> network(type=direct)
>>>>>>>                 mode(required if type=direct): bridge or vepa
>>>>>>>
>>>>>>> for macvtap: type is direct and mode can be bridge or vepa
>>>>>>> for ovs: type is bridge and mode is not required
>>>>>>> for virtual network: type=network(current implementation)
>>>>>>>
>>>>>>> Examples of network xml for attaching macvtap and ovs to guest 
>>>>>>> without libvirt:
>>>>>>> OVS:
>>>>>>> <interface type="bridge">
>>>>>>>   <source bridge="vswitch0"/>
>>>>>>>   <virtualport type="openvswitch"/>
>>>>>>>   <model type="virtio"/>
>>>>>>> </interface>
>>>>>>>
>>>>>>> macvtap with bridge mode:
>>>>>>> <interface type="direct">
>>>>>>>   <source dev="eth0" mode="bridge"/>
>>>>>>>   <model type="virtio"/>
>>>>>>> </interface>
>>>>>>>
>>>>>>>  macvtap with vepa mode:
>>>>>>> <interface type="direct">
>>>>>>>   <source dev="bond0" mode="vepa"/>
>>>>>>>   <model type="virtio"/>
>>>>>>> </interface>
>>>>>>>
>>>>>>
>>>>>> _______________________________________________
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>>>>>> Kimchi-devel at ovirt.org
>>>>>> http://lists.ovirt.org/mailman/listinfo/kimchi-devel
>>>>>>
>>>>>
>>>>
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>>>
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>>
>
>
>
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