Update: This blog post is deprecated by the official documentation. Please take a look at the official Networking Guide: Using SRIOV functionality. Patch set that added the official documentation: changeset.

Terms used
Term Definition
SRIOV Single Root IO Virtualization. SRIOV allows a PCIe device to appear to be multiple separate physical PCIe devices. What's SRIOV? By Scott Lowe
PF & VFPF is a physical function. VF is a virtual function. A PF is the physical PCI-e network card. A VF is a virtual network card with it's own PCI address.

This post describes how to enable Neutron SRIOV functionality on Mirantis OpenStack Juno deployed with Fuel 6.1 using Ubuntu 14.04 as host OS. This tutorial assumes you already have deployed OpenStack with OVS + vlan mode for networking. Next to that for the private interface we have selected eth3, which serves both as PF for the VFs and also as private vlan trunk for non SRIOV instances. In our environment we're using the "Intel Corporation 82599" network card which is assigned to eth3. We will create 7 VFs per PF.

I have created an ansible playbook to automate the whole process. You can view this Ansible playbook here: Fuel Ansible SRIOV Automated methods are recommended over manual configuring!

The following steps have to be taken to enable SRIOV manually for reference:

  1. Enabling Virtual Functions in the host Operating System
  2. Whitelist which PCI devices should be used for SRIOV in nova.conf on computes
  3. Configuring Neutron server for SRIOV
  4. Enabling the PCIDeviceScheduler in nova-scheduler
  5. Creating your SRIOV instance

1. Enable Virtual Functions in Host OS

First we need to make sure SRIOV is enabled in BIOS, check for VT-d and make sure it's enabled. After enabling VT-d we also need enable IOMMU on Linux by adding intel_iommu=on to kernel parameters.

vim /etc/default/grub
change "GRUB_CMDLINE_LINUX_DEFAULT="nomdmonddf nomdmonisw"
to "GRUB_CMDLINE_LINUX_DEFAULT="nomdmonddf nomdmonisw intel_iommu=on"

If you added new parameters you need to run:

update-grub
reboot

On each compute node we need to create the VFs via the PCI SYS interface.

echo '7' > /sys/class/net/eth3/device/sriov_numvfs

Now verify that the VFs have been created correctly

lspci | grep Ethernet

We just created the VFs for this session. If we would reboot the node these changes would get lost. So we also add a line to /etc/rc.local to apply these settings on a reboot. Note: The suggested way of making these settings persistent seems to be through sysfs.conf, but for some reason it did not work for me hence the rc.local workaround.

echo "echo '7' > /sys/class/net/eth3/device/sriov_numvfs" >> /etc/rc.local

Verify by rebooting your node that the settings persist.

2. Whitelist PCI devices nova.conf on computes

In /etc/nova/nova.conf add the line pci_passthrough_whitelist={ "devname": "eth3", "physical_network": "physnet2"}, this tells nova that all VFs belonging to eth3 are allowed to be passed through to VMs. Restart nova compute to let the changes have effect service restart nova-compute

3. Configuring Neutron server

Add sriovnicswitch to neutron ml2 conf

sed -i "s/mechanism_drivers =openvswitch/mechanism_drivers =openvswitch,sriovnicswitch/g" /etc/neutron/plugins/ml2/ml2_conf.ini

Find out the vendor_id and product_id of your VFs. Please note this should be the VF not the PF

lspci -nn | grep -i ethernet
87:00.0 Ethernet controller [0200]: Intel Corporation 82599 10 Gigabit Dual Port Backplane Connection [8086:10f8] (rev 01)
87:10.1 Ethernet controller [0200]: Intel Corporation 82599 Ethernet Controller Virtual Function [8086:10ed] (rev 01)
87:10.3 Ethernet controller [0200]: Intel Corporation 82599 Ethernet Controller Virtual Function [8086:10ed] (rev 01)

In our case the vendor_id is 8086 and the product_id is 10ed. We need to tell Neutron the vendor_id and product_id of the VFs that are supported.

sed -i "s/# supported_pci_vendor_devs.*=.*/supported_pci_vendor_devs = 8086:10ed/g" /etc/neutron/plugins/ml2/ml2_conf_sriov.ini

Neutron also has support for running a special sriov-agent which is able set the admin state. I didn't see any need for setting admin state, so to reduce complexity, we've disabled sriov-agent.

sed -i "s/# agent_required =.*/agent_required=false/g" /etc/neutron/plugins/ml2/ml2_conf_sriov.ini

We now need to add these new config files as parameter to the neutron-server daemon.

vim /etc/init/neutron-server.conf
change "--config-file /etc/neutron/neutron.conf"
to "--config-file /etc/neutron/neutron.conf --config-file /etc/neutron/plugin.ini --config-file /etc/neutron/plugins/ml2/ml2_conf_sriov.ini"

Restart neutron-server on every controller

service neutron-server restart

4. Enabling the PCIDeviceScheduler in nova-scheduler

On every controller node running nova-scheduler we need to add PCIDeviceScheduler to the filters.

vim /etc/nova/nova.conf
change "scheduler_default_filters=DifferentHostFilter,RetryFilter,AvailabilityZoneFilter,RamFilter,CoreFilter,DiskFilter,ComputeFilter,ComputeCapabilitiesFilter,ImagePropertiesFilter,ServerGroupAntiAffinityFilter,ServerGroupAffinityFilter"

to "scheduler_default_filters=DifferentHostFilter,RetryFilter,AvailabilityZoneFilter,RamFilter,CoreFilter,DiskFilter,ComputeFilter,ComputeCapabilitiesFilter,ImagePropertiesFilter,ServerGroupAntiAffinityFilter,ServerGroupAffinityFilter,PciPassthroughFilter"

also add the following line: "scheduler_available_filters=nova.scheduler.filters.pci_passthrough_filter.PciPassthroughFilter"
below the line: "scheduler_available_filters=nova.scheduler.filters.all_filters"

# Restart nova-scheduler
service nova-scheduler restart

5. Launching an Instance with SRIOV ports

After configuring all components we can start trying to launch an instance through the CLI or API. Horizon currently does not support creating SRIOV instances.

Get the id of the neutron network where you want the SR-IOV port to be created.

net_id=`neutron net-show net04 | grep "\ id\ " | awk '{ print $4 }'`

Create the SR-IOV port. We specify vnic_type direct, which means that this a SR-IOV port.

port_id=`neutron port-create $net_id --name sriov_port --binding:vnic_type direct | grep "\ id\ " | awk '{ print $4 }'`

Create the VM specifying that as 1st nic we want to use the previously created sr-iov port.

nova boot --flavor m1.large --image ubuntu_14.04 --nic port-id=$port_id --key-name sam test-sriov

References which deserve credit: Red Hat Documentation on using SRIOV OpenStack Wiki: SR-IOV-Passthrough-For-Networking


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