Support for SR-IOV

User should be able to deploy compute nodes with dedicated network interface into SR-IOV mode, then create direct-attached port and boot a VM with it.

Problem description

SR-IOV allows to bind network interface virtual functions to the different virtual machines like a PCI device. It gives a boost to the networking performance. This feature is already implemented in OpenStack, but requires complex discovery process and configuration.

This feature is compatible with DVR: traffic between tenant networks from or to SR-IOV enabled instances will be routed through the centralized router. L3 HA is not affected by this feature and should be working as expected.

Proposed changes

Enabling SR-IOV requires:

  • Discovering of compatible hardware and settings, and check that hardware is configured properly
  • Providing operator with information about SR-IOV compatible interfaces and whether it’s working or not
  • Making configurations on both controller and compute sides, including nova, neutron, and interface setup

Web UI

On Nodes tab, in Interfaces configuration dialog for every interface should be:

  • Information whether interface is SR-IOV capable
  • Visual controls to enable SR-IOV and configure additional parameters:
    • Input how many virtual functions should be initialized on the interface
    • Input physical network name for pci_passthrough_whitelist configuration in Nova. Defaults to physnet2

The following validation should be done in both UI and API:

  • SR-IOV can be enabled on SR-IOV capable interfaces where no networks are assigned. Physical network name could be set to any name on per interface basis, defaults to physnet2 on each interface
  • It should not be allowed to assign any network (or network role) to SR-IOV enabled interface
  • SR-IOV enabled interface(s) cannot be part of a bond

The following validation is needed in UI only:

  • In case Operator specifies physical network name not equal to physnet2, a warning should be shown that only physnet2 is going to be configured by Fuel in Neutron. Configuration of other physical networks is up to Operator or plugin. Fuel will just configure appropriate pci_passthrough_whitelist option in nova.conf for such interface and physical networks

The proposed change to Node Interfaces configuration screen will look like this:




The nailgun-agent should collect and send information about SR-IOV enabled NIC:

  • Number of available virtual functions (sriov_totalvfs)
  • SR-IOV availability (IOMMU groups should be checked)
  • PCI-ID of NIC virtual functions of this NIC (it’s same for all VFs)

Collected information should be passed to nailgun in the next format

  'meta': {
    'interfaces': [
        "sriov" : {
          "sriov_totalvfs": Number,
          "available": Boolean,
          "pci_id": String


In order to check SR-IOV availability, additional kernel parameters intel_iommu=on amd_iommu=on should be passed to bootstrap.

Data model

Information from the nailgun-agent and user input should be stored in interface_properties field of NodeNICInterface in format that described:

  • Whether SR-IOV is enabled by operator or not (enabled)
  • Number of enabled VFs (sriov_numvfs)
  • Number of available virtual functions (sriov_totalvfs)
  • SR-IOV availability (available)
  • PCI-ID of NIC virtual functions of this NIC, it’s same for all VFs (pci_id)
  • Physical network name, defaults to “physnet2” (physnet)
    "interface_properties" : {
      "sriov" : {
        "enabled": Boolean or null,
        "sriov_numvfs": Number or null,
        "sriov_totalvfs": Number, Read only,
        "available": Boolean, Read only,
        "pci_id": String, Read only,
        "physnet": String

When operator configures interface as SR-IOV:

  • Network transformations should add port using add-port action with provider sriov and fill vendor_specific attributes as following.
  • Cluster-wide parameter supported_pci_vendor_devs will be generated and contains PCI-ID of NIC virtual functions from all interfaces where operator enabled SR-IOV. If this parameter is empty, it means SR-IOV is not enabled at all.

For each SR-IOV enabled interface deployment information (astute.yaml) will be extended and will look like this:

  - action: add-port
    name: enp1s0f0
    provider: sriov
      sriov_numvfs: <NUM>
      physnet: <PHYSNET>
    - <PCI-ID>

where <NUM> is number, <PCI-ID> is string like “8086:1515” and <PHYSNET> is string with specified physical network name (defaults to “physnet2”).


Only payload for interfaces and node agent API handlers will be changed as described in Nailgun-agent and Data model sections.

Network Checker

Network checker will not be able to check traffic through SR-IOV enabled interface before and/or after deployment. So no changes in network verification are needed.


  • Additional kernel parameters intel_iommu=on amd_iommu=on should be passed to SR-IOV enabled nodes.
  • After compute nodes addition or removal, nova-scheduler and neutron-server configuration should be updated on controllers.

RPC Protocol

Only payload changes.

Fuel Client




Fuel Library

  • l23network will configure interfaces virtual functions, set them up, and store network configuration into Operating System config
  • additional filters will be enabled for nova-scheduler
  • additional mechanism driver will be enabled for Neutron
  • firewall_driver for Neutron ML2 plugin will be set to Noop
  • pci_passthrough_whitelist will be configured in nova-compute. New function will be introduced, that returns this mapping between interface name and physical network from network_scheme transformations.
  • supported_pci_vendor_devs will be configured in neutron-server directly from corresponding field from astute.yaml.


SR-IOV is more hardware-specific feature than DPDK. However, SR-IOV should provide less overhead than DPDK.

Upgrade impact


Security impact

Security Groups can not currently be used with SR-IOV enabled ports.

Notifications impact


End user impact

User interface impact described in Web UI section.

Performance impact

  • Information about PCI devices will be periodically sent by nova-compute.
  • Additional PciPassthroughFilter scheduler filter is required.

Deployment impact

  • Fuel will configure SR-IOV on enabled interfaces and add appropriate pci_passthrough_whitelist configuration option to nova.conf file:
  • VM Live Migration with SR-IOV attached instances is not supported.

Developer impact


Infrastructure impact

This feature could not be tested on virtual environment. Special lab is required for manual verification.

Documentation impact




Primary assignee:
yottatsa skolekonov
Mandatory design review:

Work Items

  • Collecting information about SR-IOV interfaces
  • Enable SR-IOV configuration in fuel-library
  • Enable SR-IOV related orchestrations
  • Support of configuring SR-IOV via fuel API
  • Support of SR-IOV on UI
  • Manual testing



Testing, QA

  • Manually test that SR-IOV is discovered properly
  • Manually test that SR-IOV is configured properly via API/CLI/WEB UI (deployment information is correct)
  • Manually test that SR-IOV is set up on nodes properly (manifests configure node interfaces properly)
  • Performance testing

Acceptance criteria

User should be able to deploy compute nodes with dedicated network interface into SR-IOV mode, then create direct-attached port and boot a VM with it.