Using DPDK and RDMA - Hardware networks | Networking

Example use of a virtual function in a pod
Using a virtual function in DPDK mode with an Intel NIC
Using a virtual function in DPDK mode with a Mellanox NIC
Using the TAP CNI to run a rootless DPDK workload with kernel access
Overview of achieving a specific DPDK line rate
Using SR-IOV and the Node Tuning Operator to achieve a DPDK line rate
Using a virtual function in RDMA mode with a Mellanox NIC
A test pod template for clusters that use OVS-DPDK on OpenStack
Additional resources

The containerized Data Plane Development Kit (DPDK) application is supported on OKD. You can use Single Root I/O Virtualization (SR-IOV) network hardware with the Data Plane Development Kit (DPDK) and with remote direct memory access (RDMA).

Before you perform any tasks in the following documentation, ensure that you installed the SR-IOV Network Operator.

Example use of a virtual function in a pod

You can run a remote direct memory access (RDMA) or a Data Plane Development Kit (DPDK) application in a pod with SR-IOV VF attached.

This example shows a pod using a virtual function (VF) in RDMA mode:

Pod spec that uses RDMA mode

apiVersion: v1
kind: Pod
metadata:
  name: rdma-app
  annotations:
    k8s.v1.cni.cncf.io/networks: sriov-rdma-mlnx
spec:
  containers:
  - name: testpmd
    image: <RDMA_image>
    imagePullPolicy: IfNotPresent
    securityContext:
      runAsUser: 0
      capabilities:
        add: ["IPC_LOCK","SYS_RESOURCE","NET_RAW"]
    command: ["sleep", "infinity"]

The following example shows a pod with a VF in DPDK mode:

Pod spec that uses DPDK mode

apiVersion: v1
kind: Pod
metadata:
  name: dpdk-app
  annotations:
    k8s.v1.cni.cncf.io/networks: sriov-dpdk-net
spec:
  containers:
  - name: testpmd
    image: <DPDK_image>
    securityContext:
      runAsUser: 0
      capabilities:
        add: ["IPC_LOCK","SYS_RESOURCE","NET_RAW"]
    volumeMounts:
    - mountPath: /dev/hugepages
      name: hugepage
    resources:
      limits:
        memory: "1Gi"
        cpu: "2"
        hugepages-1Gi: "4Gi"
      requests:
        memory: "1Gi"
        cpu: "2"
        hugepages-1Gi: "4Gi"
    command: ["sleep", "infinity"]
  volumes:
  - name: hugepage
    emptyDir:
      medium: HugePages

Using a virtual function in DPDK mode with an Intel NIC

Prerequisites

Install the OpenShift CLI (oc).
Install the SR-IOV Network Operator.
Log in as a user with cluster-admin privileges.

Procedure

Create the following SriovNetworkNodePolicy object, and then save the YAML in the intel-dpdk-node-policy.yaml file.

apiVersion: sriovnetwork.openshift.io/v1
kind: SriovNetworkNodePolicy
metadata:
  name: intel-dpdk-node-policy
  namespace: openshift-sriov-network-operator
spec:
  resourceName: intelnics
  nodeSelector:
    feature.node.kubernetes.io/network-sriov.capable: "true"
  priority: <priority>
  numVfs: <num>
  nicSelector:
    vendor: "8086"
    deviceID: "158b"
    pfNames: ["<pf_name>", ...]
    rootDevices: ["<pci_bus_id>", "..."]
  deviceType: vfio-pci (1)

1	Specify the driver type for the virtual functions to `vfio-pci`.

See the Configuring SR-IOV network devices section for a detailed explanation on each option in SriovNetworkNodePolicy.

When applying the configuration specified in a SriovNetworkNodePolicy object, the SR-IOV Operator may drain the nodes, and in some cases, reboot nodes. It may take several minutes for a configuration change to apply. Ensure that there are enough available nodes in your cluster to handle the evicted workload beforehand.

After the configuration update is applied, all the pods in openshift-sriov-network-operator namespace will change to a Running status.

Create the SriovNetworkNodePolicy object by running the following command:
```
$ oc create -f intel-dpdk-node-policy.yaml
```
Create the following SriovNetwork object, and then save the YAML in the intel-dpdk-network.yaml file.
```
apiVersion: sriovnetwork.openshift.io/v1
kind: SriovNetwork
metadata:
  name: intel-dpdk-network
  namespace: openshift-sriov-network-operator
spec:
  networkNamespace: <target_namespace>
  ipam: |-
# ... (1)
  vlan: <vlan>
  resourceName: intelnics
```
1 Specify a configuration object for the ipam CNI plugin as a YAML block scalar. The plugin manages IP address assignment for the attachment definition.

See the "Configuring SR-IOV additional network" section for a detailed explanation on each option in SriovNetwork.

An optional library, app-netutil, provides several API methods for gathering network information about a container’s parent pod.
Create the SriovNetwork object by running the following command:
```
$ oc create -f intel-dpdk-network.yaml
```

Create the following Pod spec, and then save the YAML in the intel-dpdk-pod.yaml file.

apiVersion: v1
kind: Pod
metadata:
  name: dpdk-app
  namespace: <target_namespace> (1)
  annotations:
    k8s.v1.cni.cncf.io/networks: intel-dpdk-network
spec:
  containers:
  - name: testpmd
    image: <DPDK_image> (2)
    securityContext:
      runAsUser: 0
      capabilities:
        add: ["IPC_LOCK","SYS_RESOURCE","NET_RAW"] (3)
    volumeMounts:
    - mountPath: /mnt/huge (4)
      name: hugepage
    resources:
      limits:
        openshift.io/intelnics: "1" (5)
        memory: "1Gi"
        cpu: "4" (6)
        hugepages-1Gi: "4Gi" (7)
      requests:
        openshift.io/intelnics: "1"
        memory: "1Gi"
        cpu: "4"
        hugepages-1Gi: "4Gi"
    command: ["sleep", "infinity"]
  volumes:
  - name: hugepage
    emptyDir:
      medium: HugePages

1	Specify the same `target_namespace` where the `SriovNetwork` object `intel-dpdk-network` is created. If you would like to create the pod in a different namespace, change `target_namespace` in both the `Pod` spec and the `SriovNetwork` object.
2	Specify the DPDK image which includes your application and the DPDK library used by application.
3	Specify additional capabilities required by the application inside the container for hugepage allocation, system resource allocation, and network interface access.
4	Mount a hugepage volume to the DPDK pod under `/mnt/huge`. The hugepage volume is backed by the emptyDir volume type with the medium being `Hugepages`.
5	Optional: Specify the number of DPDK devices allocated to DPDK pod. This resource request and limit, if not explicitly specified, will be automatically added by the SR-IOV network resource injector. The SR-IOV network resource injector is an admission controller component managed by the SR-IOV Operator. It is enabled by default and can be disabled by setting `enableInjector` option to `false` in the default `SriovOperatorConfig` CR.
6	Specify the number of CPUs. The DPDK pod usually requires exclusive CPUs to be allocated from the kubelet. This is achieved by setting CPU Manager policy to `static` and creating a pod with `Guaranteed` QoS.
7	Specify hugepage size `hugepages-1Gi` or `hugepages-2Mi` and the quantity of hugepages that will be allocated to the DPDK pod. Configure `2Mi` and `1Gi` hugepages separately. Configuring `1Gi` hugepage requires adding kernel arguments to Nodes. For example, adding kernel arguments `default_hugepagesz=1GB`, `hugepagesz=1G` and `hugepages=16` will result in `16*1Gi` hugepages be allocated during system boot.

Create the DPDK pod by running the following command:
```
$ oc create -f intel-dpdk-pod.yaml
```

Using a virtual function in DPDK mode with a Mellanox NIC

You can create a network node policy and create a Data Plane Development Kit (DPDK) pod using a virtual function in DPDK mode with a Mellanox NIC.

Prerequisites

You have installed the OpenShift CLI (oc).
You have installed the Single Root I/O Virtualization (SR-IOV) Network Operator.
You have logged in as a user with cluster-admin privileges.

Procedure

Save the following SriovNetworkNodePolicy YAML configuration to an mlx-dpdk-node-policy.yaml file:

apiVersion: sriovnetwork.openshift.io/v1
kind: SriovNetworkNodePolicy
metadata:
  name: mlx-dpdk-node-policy
  namespace: openshift-sriov-network-operator
spec:
  resourceName: mlxnics
  nodeSelector:
    feature.node.kubernetes.io/network-sriov.capable: "true"
  priority: <priority>
  numVfs: <num>
  nicSelector:
    vendor: "15b3"
    deviceID: "1015" (1)
    pfNames: ["<pf_name>", ...]
    rootDevices: ["<pci_bus_id>", "..."]
  deviceType: netdevice (2)
  isRdma: true (3)

1	Specify the device hex code of the SR-IOV network device.
2	Specify the driver type for the virtual functions to `netdevice`. A Mellanox SR-IOV Virtual Function (VF) can work in DPDK mode without using the `vfio-pci` device type. The VF device appears as a kernel network interface inside a container.
3	Enable Remote Direct Memory Access (RDMA) mode. This is required for Mellanox cards to work in DPDK mode.

See Configuring an SR-IOV network device for a detailed explanation of each option in the SriovNetworkNodePolicy object.

When applying the configuration specified in an SriovNetworkNodePolicy object, the SR-IOV Operator might drain the nodes, and in some cases, reboot nodes. It might take several minutes for a configuration change to apply. Ensure that there are enough available nodes in your cluster to handle the evicted workload beforehand.

After the configuration update is applied, all the pods in the openshift-sriov-network-operator namespace will change to a Running status.

Create the SriovNetworkNodePolicy object by running the following command:
```
$ oc create -f mlx-dpdk-node-policy.yaml
```

Save the following SriovNetwork YAML configuration to an mlx-dpdk-network.yaml file:

apiVersion: sriovnetwork.openshift.io/v1
kind: SriovNetwork
metadata:
  name: mlx-dpdk-network
  namespace: openshift-sriov-network-operator
spec:
  networkNamespace: <target_namespace>
  ipam: |- (1)
...
  vlan: <vlan>
  resourceName: mlxnics

1	Specify a configuration object for the IP Address Management (IPAM) Container Network Interface (CNI) plugin as a YAML block scalar. The plugin manages IP address assignment for the attachment definition.

See Configuring an SR-IOV network device for a detailed explanation on each option in the SriovNetwork object.

The app-netutil option library provides several API methods for gathering network information about the parent pod of a container.

Create the SriovNetwork object by running the following command:
```
$ oc create -f mlx-dpdk-network.yaml
```

Save the following Pod YAML configuration to an mlx-dpdk-pod.yaml file:

apiVersion: v1
kind: Pod
metadata:
  name: dpdk-app
  namespace: <target_namespace> (1)
  annotations:
    k8s.v1.cni.cncf.io/networks: mlx-dpdk-network
spec:
  containers:
  - name: testpmd
    image: <DPDK_image> (2)
    securityContext:
      runAsUser: 0
      capabilities:
        add: ["IPC_LOCK","SYS_RESOURCE","NET_RAW"] (3)
    volumeMounts:
    - mountPath: /mnt/huge (4)
      name: hugepage
    resources:
      limits:
        openshift.io/mlxnics: "1" (5)
        memory: "1Gi"
        cpu: "4" (6)
        hugepages-1Gi: "4Gi" (7)
      requests:
        openshift.io/mlxnics: "1"
        memory: "1Gi"
        cpu: "4"
        hugepages-1Gi: "4Gi"
    command: ["sleep", "infinity"]
  volumes:
  - name: hugepage
    emptyDir:
      medium: HugePages

1	Specify the same `target_namespace` where `SriovNetwork` object `mlx-dpdk-network` is created. To create the pod in a different namespace, change `target_namespace` in both the `Pod` spec and `SriovNetwork` object.
2	Specify the DPDK image which includes your application and the DPDK library used by the application.
3	Specify additional capabilities required by the application inside the container for hugepage allocation, system resource allocation, and network interface access.
4	Mount the hugepage volume to the DPDK pod under `/mnt/huge`. The hugepage volume is backed by the `emptyDir` volume type with the medium being `Hugepages`.
5	Optional: Specify the number of DPDK devices allocated for the DPDK pod. If not explicitly specified, this resource request and limit is automatically added by the SR-IOV network resource injector. The SR-IOV network resource injector is an admission controller component managed by SR-IOV Operator. It is enabled by default and can be disabled by setting the `enableInjector` option to `false` in the default `SriovOperatorConfig` CR.
6	Specify the number of CPUs. The DPDK pod usually requires that exclusive CPUs be allocated from the kubelet. To do this, set the CPU Manager policy to `static` and create a pod with `Guaranteed` Quality of Service (QoS).
7	Specify hugepage size `hugepages-1Gi` or `hugepages-2Mi` and the quantity of hugepages that will be allocated to the DPDK pod. Configure `2Mi` and `1Gi` hugepages separately. Configuring `1Gi` hugepages requires adding kernel arguments to Nodes.

Create the DPDK pod by running the following command:
```
$ oc create -f mlx-dpdk-pod.yaml
```

Using the TAP CNI to run a rootless DPDK workload with kernel access

DPDK applications can use virtio-user as an exception path to inject certain types of packets, such as log messages, into the kernel for processing. For more information about this feature, see Virtio_user as Exception Path.

In OpenShift Container Platform version 4.14 and later, you can use non-privileged pods to run DPDK applications alongside the tap CNI plugin. To enable this functionality, you need to mount the vhost-net device by setting the needVhostNet parameter to true within the SriovNetworkNodePolicy object.

Figure 1. DPDK and TAP example configuration

Prerequisites

You have installed the OpenShift CLI (oc).
You have installed the SR-IOV Network Operator.
You are logged in as a user with cluster-admin privileges.
Ensure that setsebools container_use_devices=on is set as root on all nodes.

Use the Machine Config Operator to set this SELinux boolean.

Procedure

Create a file, such as test-namespace.yaml, with content like the following example:

apiVersion: v1
kind: Namespace
metadata:
  name: test-namespace
  labels:
    pod-security.kubernetes.io/enforce: privileged
    pod-security.kubernetes.io/audit: privileged
    pod-security.kubernetes.io/warn: privileged
    security.openshift.io/scc.podSecurityLabelSync: "false"

Create the new Namespace object by running the following command:
```
$ oc apply -f test-namespace.yaml
```

Create a file, such as sriov-node-network-policy.yaml, with content like the following example::

apiVersion: sriovnetwork.openshift.io/v1
kind: SriovNetworkNodePolicy
metadata:
 name: sriovnic
 namespace: openshift-sriov-network-operator
spec:
 deviceType: netdevice (1)
 isRdma: true (2)
 needVhostNet: true (3)
 nicSelector:
   vendor: "15b3" (4)
   deviceID: "101b" (5)
   rootDevices: ["00:05.0"]
 numVfs: 10
 priority: 99
 resourceName: sriovnic
 nodeSelector:
    feature.node.kubernetes.io/network-sriov.capable: "true"

1	This indicates that the profile is tailored specifically for Mellanox Network Interface Controllers (NICs).
2	Setting `isRdma` to `true` is only required for a Mellanox NIC.
3	This mounts the `/dev/net/tun` and `/dev/vhost-net` devices into the container so the application can create a tap device and connect the tap device to the DPDK workload.
4	The vendor hexadecimal code of the SR-IOV network device. The value 15b3 is associated with a Mellanox NIC.
5	The device hexadecimal code of the SR-IOV network device.

Create the SriovNetworkNodePolicy object by running the following command:
```
$ oc create -f sriov-node-network-policy.yaml
```
Create the following SriovNetwork object, and then save the YAML in the sriov-network-attachment.yaml file:
```
apiVersion: sriovnetwork.openshift.io/v1
kind: SriovNetwork
metadata:
 name: sriov-network
 namespace: openshift-sriov-network-operator
spec:
 networkNamespace: test-namespace
 resourceName: sriovnic
 spoofChk: "off"
 trust: "on"
```
See the "Configuring SR-IOV additional network" section for a detailed explanation on each option in SriovNetwork.

An optional library, app-netutil, provides several API methods for gathering network information about a container’s parent pod.
Create the SriovNetwork object by running the following command:
```
$ oc create -f sriov-network-attachment.yaml
```

Create a file, such as tap-example.yaml, that defines a network attachment definition, with content like the following example:

apiVersion: "k8s.cni.cncf.io/v1"
kind: NetworkAttachmentDefinition
metadata:
 name: tap-one
 namespace: test-namespace (1)
spec:
 config: '{
   "cniVersion": "0.4.0",
   "name": "tap",
   "plugins": [
     {
        "type": "tap",
        "multiQueue": true,
        "selinuxcontext": "system_u:system_r:container_t:s0"
     },
     {
       "type":"tuning",
       "capabilities":{
         "mac":true
       }
     }
   ]
 }'

1	Specify the same `target_namespace` where the `SriovNetwork` object is created.

Create the NetworkAttachmentDefinition object by running the following command:
```
$ oc apply -f tap-example.yaml
```

Create a file, such as dpdk-pod-rootless.yaml, with content like the following example:

apiVersion: v1
kind: Pod
metadata:
  name: dpdk-app
  namespace: test-namespace (1)
  annotations:
    k8s.v1.cni.cncf.io/networks: '[
      {"name": "sriov-network", "namespace": "test-namespace"},
      {"name": "tap-one", "interface": "ext0", "namespace": "test-namespace"}]'
spec:
  nodeSelector:
    kubernetes.io/hostname: "worker-0"
  securityContext:
      fsGroup: 1001 (2)
      runAsGroup: 1001 (3)
      seccompProfile:
        type: RuntimeDefault
  containers:
  - name: testpmd
    image: <DPDK_image> (4)
    securityContext:
      capabilities:
        drop: ["ALL"] (5)
        add: (6)
          - IPC_LOCK
          - NET_RAW #for mlx only (7)
      runAsUser: 1001 (8)
      privileged: false (9)
      allowPrivilegeEscalation: true (10)
      runAsNonRoot: true (11)
    volumeMounts:
    - mountPath: /mnt/huge (12)
      name: hugepages
    resources:
      limits:
        openshift.io/sriovnic: "1" (13)
        memory: "1Gi"
        cpu: "4" (14)
        hugepages-1Gi: "4Gi" (15)
      requests:
        openshift.io/sriovnic: "1"
        memory: "1Gi"
        cpu: "4"
        hugepages-1Gi: "4Gi"
    command: ["sleep", "infinity"]
  runtimeClassName: performance-cnf-performanceprofile (16)
  volumes:
  - name: hugepages
    emptyDir:
      medium: HugePages

1	Specify the same `target_namespace` in which the `SriovNetwork` object is created. If you want to create the pod in a different namespace, change `target_namespace` in both the `Pod` spec and the `SriovNetwork` object.
2	Sets the group ownership of volume-mounted directories and files created in those volumes.
3	Specify the primary group ID used for running the container.
4	Specify the DPDK image that contains your application and the DPDK library used by application.
5	Removing all capabilities (`ALL`) from the container’s securityContext means that the container has no special privileges beyond what is necessary for normal operation.
6	Specify additional capabilities required by the application inside the container for hugepage allocation, system resource allocation, and network interface access. These capabilities must also be set in the binary file by using the `setcap` command.
7	Mellanox network interface controller (NIC) requires the `NET_RAW` capability.
8	Specify the user ID used for running the container.
9	This setting indicates that the container or containers within the pod should not be granted privileged access to the host system.
10	This setting allows a container to escalate its privileges beyond the initial non-root privileges it might have been assigned.
11	This setting ensures that the container runs with a non-root user. This helps enforce the principle of least privilege, limiting the potential impact of compromising the container and reducing the attack surface.
12	Mount a hugepage volume to the DPDK pod under `/mnt/huge`. The hugepage volume is backed by the emptyDir volume type with the medium being `Hugepages`.
13	Optional: Specify the number of DPDK devices allocated for the DPDK pod. If not explicitly specified, this resource request and limit is automatically added by the SR-IOV network resource injector. The SR-IOV network resource injector is an admission controller component managed by SR-IOV Operator. It is enabled by default and can be disabled by setting the `enableInjector` option to `false` in the default `SriovOperatorConfig` CR.
14	Specify the number of CPUs. The DPDK pod usually requires exclusive CPUs to be allocated from the kubelet. This is achieved by setting CPU Manager policy to `static` and creating a pod with `Guaranteed` QoS.
15	Specify hugepage size `hugepages-1Gi` or `hugepages-2Mi` and the quantity of hugepages that will be allocated to the DPDK pod. Configure `2Mi` and `1Gi` hugepages separately. Configuring `1Gi` hugepage requires adding kernel arguments to Nodes. For example, adding kernel arguments `default_hugepagesz=1GB`, `hugepagesz=1G` and `hugepages=16` will result in `16*1Gi` hugepages be allocated during system boot.
16	If your performance profile is not named `cnf-performance profile`, replace that string with the correct performance profile name.

Create the DPDK pod by running the following command:
```
$ oc create -f dpdk-pod-rootless.yaml
```

Additional resources

Overview of achieving a specific DPDK line rate

To achieve a specific Data Plane Development Kit (DPDK) line rate, deploy a Node Tuning Operator and configure Single Root I/O Virtualization (SR-IOV). You must also tune the DPDK settings for the following resources:

Isolated CPUs
Hugepages
The topology scheduler

In previous versions of OKD, the Performance Addon Operator was used to implement automatic tuning to achieve low latency performance for OKD applications. In OKD 4.11 and later, this functionality is part of the Node Tuning Operator.

DPDK test environment

The following diagram shows the components of a traffic-testing environment:

Traffic generator: An application that can generate high-volume packet traffic.
SR-IOV-supporting NIC: A network interface card compatible with SR-IOV. The card runs a number of virtual functions on a physical interface.
Physical Function (PF): A PCI Express (PCIe) function of a network adapter that supports the SR-IOV interface.
Virtual Function (VF): A lightweight PCIe function on a network adapter that supports SR-IOV. The VF is associated with the PCIe PF on the network adapter. The VF represents a virtualized instance of the network adapter.
Switch: A network switch. Nodes can also be connected back-to-back.
testpmd: An example application included with DPDK. The testpmd application can be used to test the DPDK in a packet-forwarding mode. The testpmd application is also an example of how to build a fully-fledged application using the DPDK Software Development Kit (SDK).
worker 0 and worker 1: OKD nodes.

Using SR-IOV and the Node Tuning Operator to achieve a DPDK line rate

You can use the Node Tuning Operator to configure isolated CPUs, hugepages, and a topology scheduler. You can then use the Node Tuning Operator with Single Root I/O Virtualization (SR-IOV) to achieve a specific Data Plane Development Kit (DPDK) line rate.

Prerequisites

You have installed the OpenShift CLI (oc).
You have installed the SR-IOV Network Operator.
You have logged in as a user with cluster-admin privileges.

You have deployed a standalone Node Tuning Operator.

In previous versions of OKD, the Performance Addon Operator was used to implement automatic tuning to achieve low latency performance for OpenShift applications. In OKD 4.11 and later, this functionality is part of the Node Tuning Operator.

Procedure

Create a PerformanceProfile object based on the following example:

apiVersion: performance.openshift.io/v2
kind: PerformanceProfile
metadata:
  name: performance
spec:
  globallyDisableIrqLoadBalancing: true
  cpu:
    isolated: 21-51,73-103 (1)
    reserved: 0-20,52-72 (2)
  hugepages:
    defaultHugepagesSize: 1G (3)
    pages:
      - count: 32
        size: 1G
  net:
    userLevelNetworking: true
  numa:
    topologyPolicy: "single-numa-node"
  nodeSelector:
    node-role.kubernetes.io/worker-cnf: ""

1	If hyperthreading is enabled on the system, allocate the relevant symbolic links to the `isolated` and `reserved` CPU groups. If the system contains multiple non-uniform memory access nodes (NUMAs), allocate CPUs from both NUMAs to both groups. You can also use the Performance Profile Creator for this task. For more information, see Creating a performance profile.
2	You can also specify a list of devices that will have their queues set to the reserved CPU count. For more information, see Reducing NIC queues using the Node Tuning Operator.
3	Allocate the number and size of hugepages needed. You can specify the NUMA configuration for the hugepages. By default, the system allocates an even number to every NUMA node on the system. If needed, you can request the use of a realtime kernel for the nodes. See Provisioning a worker with real-time capabilities for more information.

Save the yaml file as mlx-dpdk-perfprofile-policy.yaml.
Apply the performance profile using the following command:
```
$ oc create -f mlx-dpdk-perfprofile-policy.yaml
```

DPDK library for use with container applications

An optional library, app-netutil, provides several API methods for gathering network information about a pod from within a container running within that pod.

This library can assist with integrating SR-IOV virtual functions (VFs) in Data Plane Development Kit (DPDK) mode into the container. The library provides both a Golang API and a C API.

Currently there are three API methods implemented:

GetCPUInfo(): This function determines which CPUs are available to the container and returns the list.
GetHugepages(): This function determines the amount of huge page memory requested in the Pod spec for each container and returns the values.
GetInterfaces(): This function determines the set of interfaces in the container and returns the list. The return value includes the interface type and type-specific data for each interface.

The repository for the library includes a sample Dockerfile to build a container image, dpdk-app-centos. The container image can run one of the following DPDK sample applications, depending on an environment variable in the pod specification: l2fwd, l3wd or testpmd. The container image provides an example of integrating the app-netutil library into the container image itself. The library can also integrate into an init container. The init container can collect the required data and pass the data to an existing DPDK workload.

Example SR-IOV Network Operator for virtual functions

You can use the Single Root I/O Virtualization (SR-IOV) Network Operator to allocate and configure Virtual Functions (VFs) from SR-IOV-supporting Physical Function NICs on the nodes.

For more information on deploying the Operator, see Installing the SR-IOV Network Operator. For more information on configuring an SR-IOV network device, see Configuring an SR-IOV network device.

There are some differences between running Data Plane Development Kit (DPDK) workloads on Intel VFs and Mellanox VFs. This section provides object configuration examples for both VF types. The following is an example of an sriovNetworkNodePolicy object used to run DPDK applications on Intel NICs:

apiVersion: sriovnetwork.openshift.io/v1
kind: SriovNetworkNodePolicy
metadata:
  name: dpdk-nic-1
  namespace: openshift-sriov-network-operator
spec:
  deviceType: vfio-pci (1)
  needVhostNet: true (2)
  nicSelector:
    pfNames: ["ens3f0"]
  nodeSelector:
    node-role.kubernetes.io/worker-cnf: ""
  numVfs: 10
  priority: 99
  resourceName: dpdk_nic_1
---
apiVersion: sriovnetwork.openshift.io/v1
kind: SriovNetworkNodePolicy
metadata:
  name: dpdk-nic-1
  namespace: openshift-sriov-network-operator
spec:
  deviceType: vfio-pci
  needVhostNet: true
  nicSelector:
    pfNames: ["ens3f1"]
  nodeSelector:
  node-role.kubernetes.io/worker-cnf: ""
  numVfs: 10
  priority: 99
  resourceName: dpdk_nic_2

1	For Intel NICs, `deviceType` must be `vfio-pci`.
2	If kernel communication with DPDK workloads is required, add `needVhostNet: true`. This mounts the `/dev/net/tun` and `/dev/vhost-net` devices into the container so the application can create a tap device and connect the tap device to the DPDK workload.

The following is an example of an sriovNetworkNodePolicy object for Mellanox NICs:

apiVersion: sriovnetwork.openshift.io/v1
kind: SriovNetworkNodePolicy
metadata:
  name: dpdk-nic-1
  namespace: openshift-sriov-network-operator
spec:
  deviceType: netdevice (1)
  isRdma: true (2)
  nicSelector:
    rootDevices:
      - "0000:5e:00.1"
  nodeSelector:
    node-role.kubernetes.io/worker-cnf: ""
  numVfs: 5
  priority: 99
  resourceName: dpdk_nic_1
---
apiVersion: sriovnetwork.openshift.io/v1
kind: SriovNetworkNodePolicy
metadata:
  name: dpdk-nic-2
  namespace: openshift-sriov-network-operator
spec:
  deviceType: netdevice
  isRdma: true
  nicSelector:
    rootDevices:
      - "0000:5e:00.0"
  nodeSelector:
    node-role.kubernetes.io/worker-cnf: ""
  numVfs: 5
  priority: 99
  resourceName: dpdk_nic_2

1	For Mellanox devices the `deviceType` must be `netdevice`.
2	For Mellanox devices `isRdma` must be `true`. Mellanox cards are connected to DPDK applications using Flow Bifurcation. This mechanism splits traffic between Linux user space and kernel space, and can enhance line rate processing capability.

Example SR-IOV network operator

The following is an example definition of an sriovNetwork object. In this case, Intel and Mellanox configurations are identical:

apiVersion: sriovnetwork.openshift.io/v1
kind: SriovNetwork
metadata:
  name: dpdk-network-1
  namespace: openshift-sriov-network-operator
spec:
  ipam: '{"type": "host-local","ranges": [[{"subnet": "10.0.1.0/24"}]],"dataDir":
   "/run/my-orchestrator/container-ipam-state-1"}' (1)
  networkNamespace: dpdk-test (2)
  spoofChk: "off"
  trust: "on"
  resourceName: dpdk_nic_1 (3)
---
apiVersion: sriovnetwork.openshift.io/v1
kind: SriovNetwork
metadata:
  name: dpdk-network-2
  namespace: openshift-sriov-network-operator
spec:
  ipam: '{"type": "host-local","ranges": [[{"subnet": "10.0.2.0/24"}]],"dataDir":
   "/run/my-orchestrator/container-ipam-state-1"}'
  networkNamespace: dpdk-test
  spoofChk: "off"
  trust: "on"
  resourceName: dpdk_nic_2

1	You can use a different IP Address Management (IPAM) implementation, such as Whereabouts. For more information, see Dynamic IP address assignment configuration with Whereabouts.
2	You must request the `networkNamespace` where the network attachment definition will be created. You must create the `sriovNetwork` CR under the `openshift-sriov-network-operator` namespace.
3	The `resourceName` value must match that of the `resourceName` created under the `sriovNetworkNodePolicy`.

Example DPDK base workload

The following is an example of a Data Plane Development Kit (DPDK) container:

apiVersion: v1
kind: Namespace
metadata:
  name: dpdk-test
---
apiVersion: v1
kind: Pod
metadata:
  annotations:
    k8s.v1.cni.cncf.io/networks: '[ (1)
     {
      "name": "dpdk-network-1",
      "namespace": "dpdk-test"
     },
     {
      "name": "dpdk-network-2",
      "namespace": "dpdk-test"
     }
   ]'
    irq-load-balancing.crio.io: "disable" (2)
    cpu-load-balancing.crio.io: "disable"
    cpu-quota.crio.io: "disable"
  labels:
    app: dpdk
  name: testpmd
  namespace: dpdk-test
spec:
  runtimeClassName: performance-performance (3)
  containers:
    - command:
        - /bin/bash
        - -c
        - sleep INF
      image: registry.redhat.io/openshift4/dpdk-base-rhel8
      imagePullPolicy: Always
      name: dpdk
      resources: (4)
        limits:
          cpu: "16"
          hugepages-1Gi: 8Gi
          memory: 2Gi
        requests:
          cpu: "16"
          hugepages-1Gi: 8Gi
          memory: 2Gi
      securityContext:
        capabilities:
          add:
            - IPC_LOCK
            - SYS_RESOURCE
            - NET_RAW
            - NET_ADMIN
        runAsUser: 0
      volumeMounts:
        - mountPath: /mnt/huge
          name: hugepages
  terminationGracePeriodSeconds: 5
  volumes:
    - emptyDir:
        medium: HugePages
      name: hugepages

1	Request the SR-IOV networks you need. Resources for the devices will be injected automatically.
2	Disable the CPU and IRQ load balancing base. See Disabling interrupt processing for individual pods for more information.
3	Set the `runtimeClass` to `performance-performance`. Do not set the `runtimeClass` to `HostNetwork` or `privileged`.
4	Request an equal number of resources for requests and limits to start the pod with `Guaranteed` Quality of Service (QoS).

Do not start the pod with SLEEP and then exec into the pod to start the testpmd or the DPDK workload. This can add additional interrupts as the exec process is not pinned to any CPU.

Example testpmd script

The following is an example script for running testpmd:

#!/bin/bash
set -ex
export CPU=$(cat /sys/fs/cgroup/cpuset/cpuset.cpus)
echo ${CPU}

dpdk-testpmd -l ${CPU} -a ${PCIDEVICE_OPENSHIFT_IO_DPDK_NIC_1} -a ${PCIDEVICE_OPENSHIFT_IO_DPDK_NIC_2} -n 4 -- -i --nb-cores=15 --rxd=4096 --txd=4096 --rxq=7 --txq=7 --forward-mode=mac --eth-peer=0,50:00:00:00:00:01 --eth-peer=1,50:00:00:00:00:02

This example uses two different sriovNetwork CRs. The environment variable contains the Virtual Function (VF) PCI address that was allocated for the pod. If you use the same network in the pod definition, you must split the pciAddress. It is important to configure the correct MAC addresses of the traffic generator. This example uses custom MAC addresses.

Using a virtual function in RDMA mode with a Mellanox NIC

RDMA over Converged Ethernet (RoCE) is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process.

For more information about the support scope of Red Hat Technology Preview features, see Technology Preview Features Support Scope.

RDMA over Converged Ethernet (RoCE) is the only supported mode when using RDMA on OKD.

Prerequisites

Install the OpenShift CLI (oc).
Install the SR-IOV Network Operator.
Log in as a user with cluster-admin privileges.

Procedure

Create the following SriovNetworkNodePolicy object, and then save the YAML in the mlx-rdma-node-policy.yaml file.

apiVersion: sriovnetwork.openshift.io/v1
kind: SriovNetworkNodePolicy
metadata:
  name: mlx-rdma-node-policy
  namespace: openshift-sriov-network-operator
spec:
  resourceName: mlxnics
  nodeSelector:
    feature.node.kubernetes.io/network-sriov.capable: "true"
  priority: <priority>
  numVfs: <num>
  nicSelector:
    vendor: "15b3"
    deviceID: "1015" (1)
    pfNames: ["<pf_name>", ...]
    rootDevices: ["<pci_bus_id>", "..."]
  deviceType: netdevice (2)
  isRdma: true (3)

1	Specify the device hex code of the SR-IOV network device.
2	Specify the driver type for the virtual functions to `netdevice`.
3	Enable RDMA mode.

See the Configuring SR-IOV network devices section for a detailed explanation on each option in SriovNetworkNodePolicy.

After the configuration update is applied, all the pods in the openshift-sriov-network-operator namespace will change to a Running status.

Create the SriovNetworkNodePolicy object by running the following command:
```
$ oc create -f mlx-rdma-node-policy.yaml
```
Create the following SriovNetwork object, and then save the YAML in the mlx-rdma-network.yaml file.
```
apiVersion: sriovnetwork.openshift.io/v1
kind: SriovNetwork
metadata:
  name: mlx-rdma-network
  namespace: openshift-sriov-network-operator
spec:
  networkNamespace: <target_namespace>
  ipam: |- (1)
# ...
  vlan: <vlan>
  resourceName: mlxnics
```
1 Specify a configuration object for the ipam CNI plugin as a YAML block scalar. The plugin manages IP address assignment for the attachment definition.

See the "Configuring SR-IOV additional network" section for a detailed explanation on each option in SriovNetwork.

An optional library, app-netutil, provides several API methods for gathering network information about a container’s parent pod.
Create the SriovNetworkNodePolicy object by running the following command:
```
$ oc create -f mlx-rdma-network.yaml
```

Create the following Pod spec, and then save the YAML in the mlx-rdma-pod.yaml file.

apiVersion: v1
kind: Pod
metadata:
  name: rdma-app
  namespace: <target_namespace> (1)
  annotations:
    k8s.v1.cni.cncf.io/networks: mlx-rdma-network
spec:
  containers:
  - name: testpmd
    image: <RDMA_image> (2)
    securityContext:
      runAsUser: 0
      capabilities:
        add: ["IPC_LOCK","SYS_RESOURCE","NET_RAW"] (3)
    volumeMounts:
    - mountPath: /mnt/huge (4)
      name: hugepage
    resources:
      limits:
        memory: "1Gi"
        cpu: "4" (5)
        hugepages-1Gi: "4Gi" (6)
      requests:
        memory: "1Gi"
        cpu: "4"
        hugepages-1Gi: "4Gi"
    command: ["sleep", "infinity"]
  volumes:
  - name: hugepage
    emptyDir:
      medium: HugePages

1	Specify the same `target_namespace` where `SriovNetwork` object `mlx-rdma-network` is created. If you would like to create the pod in a different namespace, change `target_namespace` in both `Pod` spec and `SriovNetwork` object.
2	Specify the RDMA image which includes your application and RDMA library used by application.
3	Specify additional capabilities required by the application inside the container for hugepage allocation, system resource allocation, and network interface access.
4	Mount the hugepage volume to RDMA pod under `/mnt/huge`. The hugepage volume is backed by the emptyDir volume type with the medium being `Hugepages`.
5	Specify number of CPUs. The RDMA pod usually requires exclusive CPUs be allocated from the kubelet. This is achieved by setting CPU Manager policy to `static` and create pod with `Guaranteed` QoS.
6	Specify hugepage size `hugepages-1Gi` or `hugepages-2Mi` and the quantity of hugepages that will be allocated to the RDMA pod. Configure `2Mi` and `1Gi` hugepages separately. Configuring `1Gi` hugepage requires adding kernel arguments to Nodes.

Create the RDMA pod by running the following command:
```
$ oc create -f mlx-rdma-pod.yaml
```

A test pod template for clusters that use OVS-DPDK on OpenStack

The following testpmd pod demonstrates container creation with huge pages, reserved CPUs, and the SR-IOV port.

An example testpmd pod

apiVersion: v1
kind: Pod
metadata:
  name: testpmd-dpdk
  namespace: mynamespace
  annotations:
    cpu-load-balancing.crio.io: "disable"
    cpu-quota.crio.io: "disable"
# ...
spec:
  containers:
  - name: testpmd
    command: ["sleep", "99999"]
    image: registry.redhat.io/openshift4/dpdk-base-rhel8:v4.9
    securityContext:
      capabilities:
        add: ["IPC_LOCK","SYS_ADMIN"]
      privileged: true
      runAsUser: 0
    resources:
      requests:
        memory: 1000Mi
        hugepages-1Gi: 1Gi
        cpu: '2'
        openshift.io/dpdk1: 1 (1)
      limits:
        hugepages-1Gi: 1Gi
        cpu: '2'
        memory: 1000Mi
        openshift.io/dpdk1: 1
    volumeMounts:
      - mountPath: /mnt/huge
        name: hugepage
        readOnly: False
  runtimeClassName: performance-cnf-performanceprofile (2)
  volumes:
  - name: hugepage
    emptyDir:
      medium: HugePages

1	The name `dpdk1` in this example is a user-created `SriovNetworkNodePolicy` resource. You can substitute this name for that of a resource that you create.
2	If your performance profile is not named `cnf-performance profile`, replace that string with the correct performance profile name.