Chapter 5. Configuring PCI passthrough

Procedure

1. Log in to the undercloud as the stack user.

2. Source the stackrc file:

   [stack@director ~]$ source ~/stackrc

3. Generate a new roles data file named roles_data_pci_passthrough.yaml that includes the Controller, Compute, and ComputePCI roles:

   (undercloud)$ openstack overcloud roles \
    generate -o /home/stack/templates/roles_data_pci_passthrough.yaml \
    Compute:ComputePCI Compute Controller

4. Open roles_data_pci_passthrough.yaml and edit or add the following parameters and sections:

   Section/Parameter	Current value	New value
   Role comment	Role: Compute	Role: ComputePCI
   Role name	name: Compute	name: ComputePCI
   description	Basic Compute Node role	PCI Passthrough Compute Node role
   HostnameFormatDefault	%stackname%-novacompute-%index%	%stackname%-novacomputepci-%index%
   deprecated_nic_config_name	compute.yaml	compute-pci-passthrough.yaml

5. Register the PCI passthrough Compute nodes for the overcloud by adding them to your node definition template, node.json or node.yaml. For more information, see Registering nodes for the overcloud in the Director Installation and Usage guide.

6. Inspect the node hardware:

   (undercloud)$ openstack overcloud node introspect \
    --all-manageable --provide

   For more information, see Creating an inventory of the bare-metal node hardware in the Director Installation and Usage guide.

7. Create the compute-pci-passthrough overcloud flavor for PCI passthrough Compute nodes:

   (undercloud)$ openstack flavor create --id auto \
    --ram <ram_size_mb> --disk <disk_size_gb> \
    --vcpus <no_vcpus> compute-pci-passthrough

   • Replace <ram_size_mb> with the RAM of the bare metal node, in MB.
   • Replace <disk_size_gb> with the size of the disk on the bare metal node, in GB.

   • Replace <no_vcpus> with the number of CPUs on the bare metal node.

     Note

     These properties are not used for scheduling instances. However, the Compute scheduler does use the disk size to determine the root partition size.

8. Tag each bare metal node that you want to designate for PCI passthrough with a custom PCI passthrough resource class:

   (undercloud)$ openstack baremetal node set \
    --resource-class baremetal.PCI-PASSTHROUGH <node>

   Replace <node> with the ID of the bare metal node.

9. Associate the compute-pci-passthrough flavor with the custom PCI passthrough resource class:

   (undercloud)$ openstack flavor set \
    --property resources:CUSTOM_BAREMETAL_PCI_PASSTHROUGH=1 \
     compute-pci-passthrough

   To determine the name of a custom resource class that corresponds to a resource class of a Bare Metal service node, convert the resource class to uppercase, replace all punctuation with an underscore, and prefix with CUSTOM_.

   Note

   A flavor can request only one instance of a bare metal resource class.

10. Set the following flavor properties to prevent the Compute scheduler from using the bare metal flavor properties to schedule instances:

    (undercloud)$ openstack flavor set \
     --property resources:VCPU=0 --property resources:MEMORY_MB=0 \
     --property resources:DISK_GB=0 compute-pci-passthrough

11. Add the following parameters to the node-info.yaml file to specify the number of PCI passthrough Compute nodes, and the flavor to use for the PCI passthrough designated Compute nodes:

    parameter_defaults:
      OvercloudComputePCIFlavor: compute-pci-passthrough
      ComputePCICount: 3

12. To verify that the role was created, enter the following command:

    (undercloud)$ openstack overcloud profiles list

Procedure

1. Create an environment file to configure the Controller node on the overcloud for PCI passthrough, for example, pci_passthrough_controller.yaml.

2. Add PciPassthroughFilter to the NovaSchedulerDefaultFilters parameter in pci_passthrough_controller.yaml:

   parameter_defaults:
     NovaSchedulerDefaultFilters: ['AvailabilityZoneFilter','ComputeFilter','ComputeCapabilitiesFilter','ImagePropertiesFilter','ServerGroupAntiAffinityFilter','ServerGroupAffinityFilter','PciPassthroughFilter','NUMATopologyFilter']

3. To specify the PCI alias for the devices on the Controller node, add the following configuration to pci_passthrough_controller.yaml:

   parameter_defaults:
     ...
     ControllerExtraConfig:
       nova::pci::aliases:
         - name: "a1"
           product_id: "1572"
           vendor_id: "8086"
           device_type: "type-PF"

   For more information about configuring the device_type field, see PCI passthrough device type field.

   Note

   If the nova-api service is running in a role different from the Controller role, replace ControllerExtraConfig with the user role in the format <Role>ExtraConfig.

4. Optional: To set a default NUMA affinity policy for PCI passthrough devices, add numa_policy to the nova::pci::aliases: configuration from step 3:

   parameter_defaults:
     ...
     ControllerExtraConfig:
       nova::pci::aliases:
         - name: "a1"
           product_id: "1572"
           vendor_id: "8086"
           device_type: "type-PF"
           numa_policy: "preferred"

5. To configure the Compute node on the overcloud for PCI passthrough, create an environment file, for example, pci_passthrough_compute.yaml.

6. To specify the available PCIs for the devices on the Compute node, use the vendor_id and product_id options to add all matching PCI devices to the pool of PCI devices available for passthrough to instances. For example, to add all Intel® Ethernet Controller X710 devices to the pool of PCI devices available for passthrough to instances, add the following configuration to pci_passthrough_compute.yaml:

   parameter_defaults:
     ...
     ComputePCIParameters:
       NovaPCIPassthrough:
         - vendor_id: "8086"
           product_id: "1572"

   For more information about how to configure NovaPCIPassthrough, see Guidelines for configuring NovaPCIPassthrough.

7. You must create a copy of the PCI alias on the Compute node for instance migration and resize operations. To specify the PCI alias for the devices on the PCI passthrough Compute node, add the following to pci_passthrough_compute.yaml:

   parameter_defaults:
     ...
     ComputePCIExtraConfig:
       nova::pci::aliases:
         - name: "a1"
           product_id: "1572"
           vendor_id: "8086"
           device_type: "type-PF"

   Note

   The Compute node aliases must be identical to the aliases on the Controller node. Therefore, if you added numa_affinity to nova::pci::aliases in pci_passthrough_controller.yaml, then you must also add it to nova::pci::aliases in pci_passthrough_compute.yaml.

8. To enable IOMMU in the server BIOS of the Compute nodes to support PCI passthrough, add the KernelArgs parameter to pci_passthrough_compute.yaml. For example, use the following KernalArgs settings to enable an Intel IOMMU:

   parameter_defaults:
     ...
     ComputePCIParameters:
       KernelArgs: "intel_iommu=on iommu=pt"

   To enable an AMD IOMMU, set KernelArgs to "amd_iommu=on iommu=pt".

   Note

   When you first add the KernelArgs parameter to the configuration of a role, the overcloud nodes are automatically rebooted. If required, you can disable the automatic rebooting of nodes and instead perform node reboots manually after each overcloud deployment. For more information, see Configuring manual node reboot to define KernelArgs.

9. Add your custom environment files to the stack with your other environment files and deploy the overcloud:

   (undercloud)$ openstack overcloud deploy --templates \
     -e [your environment files] \
     -e /home/stack/templates/pci_passthrough_controller.yaml \
     -e /home/stack/templates/pci_passthrough_compute.yaml \

10. Create and configure the flavors that your cloud users can use to request the PCI devices. The following example requests two devices, each with a vendor ID of 8086 and a product ID of 1572, using the alias defined in step 7:

    (overcloud)# openstack flavor set \
     --property "pci_passthrough:alias"="a1:2" device_passthrough

11. Optional: To override the default NUMA affinity policy for PCI passthrough devices, you can add the NUMA affinity policy property key to the flavor or the image:

    • To override the default NUMA affinity policy by using the flavor, add the hw:pci_numa_affinity_policy property key:

      (overcloud)# openstack flavor set \
       --property "hw:pci_numa_affinity_policy"="required" \
       device_passthrough

      For more information about the valid values for hw:pci_numa_affinity_policy, see Flavor metadata.

    • To override the default NUMA affinity policy by using the image, add the hw_pci_numa_affinity_policy property key:

      (overcloud)# openstack image set \
       --property hw_pci_numa_affinity_policy=required \
       device_passthrough_image

      Note

      If you set the NUMA affinity policy on both the image and the flavor then the property values must match. The flavor setting takes precedence over the image and default settings. Therefore, the configuration of the NUMA affinity policy on the image only takes effect if the property is not set on the flavor.

Verification

1. Create an instance with a PCI passthrough device:

   # openstack server create --flavor device_passthrough \
    --image <image> --wait test-pci

2. Log in to the instance as a cloud user. For more information, see Connecting to an instance.

3. To verify that the PCI device is accessible from the instance, enter the following command from the instance:

   $ lspci -nn | grep <device_name>