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Adding a pod to an SR-IOV additional network

Runtime configuration for a network attachment

When attaching a pod to an additional network, you can specify a runtime configuration to make specific customizations for the pod. For example, you can request a specific MAC hardware address.

You specify the runtime configuration by setting an annotation in the pod specification. The annotation key is k8s.v1.cni.cncf.io/networks, and it accepts a JSON object that describes the runtime configuration.

Runtime configuration for an Ethernet-based SR-IOV attachment

The following JSON describes the runtime configuration options for an Ethernet-based SR-IOV network attachment.

[
  {
    "name": "<name>", (1)
    "mac": "<mac_address>", (2)
    "ips": ["<cidr_range>"] (3)
  }
]
1 The name of the SR-IOV network attachment definition CR.
2 Optional: The MAC address for the SR-IOV device that is allocated from the resource type defined in the SR-IOV network attachment definition CR. To use this feature, you also must specify { "mac": true } in the SriovNetwork object.
3 Optional: IP addresses for the SR-IOV device that is allocated from the resource type defined in the SR-IOV network attachment definition CR. Both IPv4 and IPv6 addresses are supported. To use this feature, you also must specify { "ips": true } in the SriovNetwork object.
Example runtime configuration
apiVersion: v1
kind: Pod
metadata:
  name: sample-pod
  annotations:
    k8s.v1.cni.cncf.io/networks: |-
      [
        {
          "name": "net1",
          "mac": "20:04:0f:f1:88:01",
          "ips": ["192.168.10.1/24", "2001::1/64"]
        }
      ]
spec:
  containers:
  - name: sample-container
    image: <image>
    imagePullPolicy: IfNotPresent
    command: ["sleep", "infinity"]

Adding a pod to an additional network

You can add a pod to an additional network. The pod continues to send normal cluster-related network traffic over the default network.

When a pod is created additional networks are attached to it. However, if a pod already exists, you cannot attach additional networks to it.

The pod must be in the same namespace as the additional network.

If a network attachment is managed by the SR-IOV Network Operator, the SR-IOV Network Resource Injector adds the resource field to the Pod object automatically.

When specifying an SR-IOV hardware network for a Deployment object or a ReplicationController object, you must specify the namespace of the NetworkAttachmentDefinition object. For more information, see the following bugs: BZ#1846333 and BZ#1840962.
Prerequisites

  • Install the OpenShift CLI (oc).

  • Log in to the cluster.

  • Install the SR-IOV Operator.

  • Create an SriovNetwork object to attach the pod to.

Procedure

  1. Add an annotation to the Pod object. Only one of the following annotation formats can be used:

    1. To attach an additional network without any customization, add an annotation with the following format. Replace <network> with the name of the additional network to associate with the pod:

      metadata:
  annotations:
    k8s.v1.cni.cncf.io/networks: <network>[,<network>,...] (1)
      1 To specify more than one additional network, separate each network with a comma. Do not include whitespace between the comma. If you specify the same additional network multiple times, that pod will have multiple network interfaces attached to that network.

    2. To attach an additional network with customizations, add an annotation with the following format:

      metadata:
  annotations:
    k8s.v1.cni.cncf.io/networks: |-
      [
        {
          "name": "<network>", (1)
          "namespace": "<namespace>", (2)
          "default-route": ["<default-route>"] (3)
        }
      ]
      1 Specify the name of the additional network defined by a NetworkAttachmentDefinition object.
      2 Specify the namespace where the NetworkAttachmentDefinition object is defined.
      3 Optional: Specify an override for the default route, such as 192.168.17.1.

  2. To create the pod, enter the following command. Replace <name> with the name of the pod.

    $ oc create -f <name>.yaml

  3. Optional: To Confirm that the annotation exists in the Pod CR, enter the following command, replacing <name> with the name of the pod.

    $ oc get pod <name> -o yaml

    In the following example, the example-pod pod is attached to the net1 additional network:

    $ oc get pod example-pod -o yaml
apiVersion: v1
kind: Pod
metadata:
  annotations:
    k8s.v1.cni.cncf.io/networks: macvlan-bridge
    k8s.v1.cni.cncf.io/networks-status: |- (1)
      [{
          "name": "openshift-sdn",
          "interface": "eth0",
          "ips": [
              "10.128.2.14"
          ],
          "default": true,
          "dns": {}
      },{
          "name": "macvlan-bridge",
          "interface": "net1",
          "ips": [
              "20.2.2.100"
          ],
          "mac": "22:2f:60:a5:f8:00",
          "dns": {}
      }]
  name: example-pod
  namespace: default
spec:
  ...
status:
  ...
    1 The k8s.v1.cni.cncf.io/networks-status parameter is a JSON array of objects. Each object describes the status of an additional network attached to the pod. The annotation value is stored as a plain text value.

Creating a non-uniform memory access (NUMA) aligned SR-IOV pod

You can create a NUMA aligned SR-IOV pod by restricting SR-IOV and the CPU resources allocated from the same NUMA node with restricted or single-numa-node Topology Manager polices.

Prerequisites

  • Install the OpenShift CLI (oc).

  • Enable a LatencySensitive profile and configure the CPU Manager policy to static.

Procedure

  1. Create the following SR-IOV pod spec, and then save the YAML in the <name>-sriov-pod.yaml file. Replace <name> with a name for this pod.

    The following example shows an SR-IOV pod spec:

    apiVersion: v1
kind: Pod
metadata:
  name: sample-pod
  annotations:
    k8s.v1.cni.cncf.io/networks: <name> (1)
spec:
  containers:
  - name: sample-container
    image: <image> (2)
    command: ["sleep", "infinity"]
    resources:
      limits:
        memory: "1Gi" (3)
        cpu: "2" (4)
      requests:
        memory: "1Gi"
        cpu: "2"
    1 Replace <name> with the name of the SR-IOV network attachment definition CR.
    2 Replace <image> with the name of the sample-pod image.
    3 To create the SR-IOV pod with guaranteed QoS, set memory limits equal to memory requests.
    4 To create the SR-IOV pod with guaranteed QoS, set cpu limits equals to cpu requests.

  2. Create the sample SR-IOV pod by running the following command:

    $ oc create -f <filename> (1)
    1 Replace <filename> with the name of the file you created in the previous step.

  3. Confirm that the sample-pod is configured with guaranteed QoS.

    $ oc describe pod sample-pod

  4. Confirm that the sample-pod is allocated with exclusive CPUs.

    $ oc exec sample-pod -- cat /sys/fs/cgroup/cpuset/cpuset.cpus

  5. Confirm that the SR-IOV device and CPUs that are allocated for the sample-pod are on the same NUMA node.

    $ oc exec sample-pod -- cat /sys/fs/cgroup/cpuset/cpuset.cpus

Additional resources