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Configuring an SR-IOV InfiniBand network attachment

InfiniBand device configuration object

You can configure an InfiniBand (IB) network device by defining an SriovIBNetwork object.

The following YAML describes an SriovIBNetwork object:

apiVersion: sriovnetwork.openshift.io/v1
kind: SriovIBNetwork
metadata:
  name: <name> (1)
  namespace: openshift-sriov-network-operator (2)
spec:
  resourceName: <sriov_resource_name> (3)
  networkNamespace: <target_namespace> (4)
  ipam: |- (5)
    {}
  linkState: <link_state> (6)
  capabilities: <capabilities> (7)
1 A name for the object. The SR-IOV Network Operator creates a NetworkAttachmentDefinition object with same name.
2 The namespace where the SR-IOV Operator is installed.
3 The value for the spec.resourceName parameter from the SriovNetworkNodePolicy object that defines the SR-IOV hardware for this additional network.
4 The target namespace for the SriovIBNetwork object. Only pods in the target namespace can attach to the network device.
5 Optional: A configuration object for the IPAM CNI plugin as a YAML block scalar. The plugin manages IP address assignment for the attachment definition.
6 Optional: The link state of virtual function (VF). Allowed values are enable, disable and auto.
7 Optional: The capabilities to configure for this network. You can specify '{ "ips": true }' to enable IP address support or '{ "infinibandGUID": true }' to enable IB Global Unique Identifier (GUID) support.

Creating a configuration for assignment of dual-stack IP addresses dynamically

Dual-stack IP address assignment can be configured with the ipRanges parameter for:

  • IPv4 addresses

  • IPv6 addresses

  • multiple IP address assignment

Procedure

  1. Set type to whereabouts.

  2. Use ipRanges to allocate IP addresses as shown in the following example:

    cniVersion: operator.openshift.io/v1
kind: Network
=metadata:
  name: cluster
spec:
  additionalNetworks:
  - name: whereabouts-shim
    namespace: default
    type: Raw
    rawCNIConfig: |-
      {
       "name": "whereabouts-dual-stack",
       "cniVersion": "0.3.1,
       "type": "bridge",
       "ipam": {
         "type": "whereabouts",
         "ipRanges": [
                  {"range": "192.168.10.0/24"},
                  {"range": "2001:db8::/64"}
              ]
       }
      }

  3. Attach network to a pod. For more information, see "Adding a pod to an additional network".

  4. Verify that all IP addresses are assigned.

  5. Run the following command to ensure the IP addresses are assigned as metadata.

    $ oc exec -it mypod -- ip a

Configuration of IP address assignment for a network attachment

For additional networks, IP addresses can be assigned using an IP Address Management (IPAM) CNI plugin, which supports various assignment methods, including Dynamic Host Configuration Protocol (DHCP) and static assignment.

The DHCP IPAM CNI plugin responsible for dynamic assignment of IP addresses operates with two distinct components:

  • CNI Plugin: Responsible for integrating with the Kubernetes networking stack to request and release IP addresses.

  • DHCP IPAM CNI Daemon: A listener for DHCP events that coordinates with existing DHCP servers in the environment to handle IP address assignment requests. This daemon is not a DHCP server itself.

For networks requiring type: dhcp in their IPAM configuration, ensure the following:

  • A DHCP server is available and running in the environment. The DHCP server is external to the cluster and is expected to be part of the customer’s existing network infrastructure.

  • The DHCP server is appropriately configured to serve IP addresses to the nodes.

In cases where a DHCP server is unavailable in the environment, it is recommended to use the Whereabouts IPAM CNI plugin instead. The Whereabouts CNI provides similar IP address management capabilities without the need for an external DHCP server.

Use the Whereabouts CNI plugin when there is no external DHCP server or where static IP address management is preferred. The Whereabouts plugin includes a reconciler daemon to manage stale IP address allocations.

A DHCP lease must be periodically renewed throughout the container’s lifetime, so a separate daemon, the DHCP IPAM CNI Daemon, is required. To deploy the DHCP IPAM CNI daemon, modify the Cluster Network Operator (CNO) configuration to trigger the deployment of this daemon as part of the additional network setup.

Static IP address assignment configuration

The following table describes the configuration for static IP address assignment:

Table 1. ipam static configuration object
Field Type Description

type

string

The IPAM address type. The value static is required.

addresses

array

An array of objects specifying IP addresses to assign to the virtual interface. Both IPv4 and IPv6 IP addresses are supported.

routes

array

An array of objects specifying routes to configure inside the pod.

dns

array

Optional: An array of objects specifying the DNS configuration.

The addresses array requires objects with the following fields:

Table 2. ipam.addresses[] array
Field Type Description

address

string

An IP address and network prefix that you specify. For example, if you specify 10.10.21.10/24, then the additional network is assigned an IP address of 10.10.21.10 and the netmask is 255.255.255.0.

gateway

string

The default gateway to route egress network traffic to.
Table 3. ipam.routes[] array
Field Type Description

dst

string

The IP address range in CIDR format, such as 192.168.17.0/24 or 0.0.0.0/0 for the default route.

gw

string

The gateway where network traffic is routed.
Table 4. ipam.dns object
Field Type Description

nameservers

array

An array of one or more IP addresses for to send DNS queries to.

domain

array

The default domain to append to a hostname. For example, if the domain is set to example.com, a DNS lookup query for example-host is rewritten as example-host.example.com.

search

array

An array of domain names to append to an unqualified hostname, such as example-host, during a DNS lookup query.
Static IP address assignment configuration example

{
  "ipam": {
    "type": "static",
      "addresses": [
        {
          "address": "191.168.1.7/24"
        }
      ]
  }
}

Dynamic IP address (DHCP) assignment configuration

A pod obtains its original DHCP lease when it is created. The lease must be periodically renewed by a minimal DHCP server deployment running on the cluster.

For an Ethernet network attachment, the SR-IOV Network Operator does not create a DHCP server deployment; the Cluster Network Operator is responsible for creating the minimal DHCP server deployment.

To trigger the deployment of the DHCP server, you must create a shim network attachment by editing the Cluster Network Operator configuration, as in the following example:

Example shim network attachment definition

apiVersion: operator.openshift.io/v1
kind: Network
metadata:
  name: cluster
spec:
  additionalNetworks:
  - name: dhcp-shim
    namespace: default
    type: Raw
    rawCNIConfig: |-
      {
        "name": "dhcp-shim",
        "cniVersion": "0.3.1",
        "type": "bridge",
        "ipam": {
          "type": "dhcp"
        }
      }
  # ...

The following table describes the configuration parameters for dynamic IP address address assignment with DHCP.

Table 5. ipam DHCP configuration object
Field Type Description

type

string

The IPAM address type. The value dhcp is required.

The following JSON example describes the configuration p for dynamic IP address address assignment with DHCP.

Dynamic IP address (DHCP) assignment configuration example

{
  "ipam": {
    "type": "dhcp"
  }
}

Dynamic IP address assignment configuration with Whereabouts

The Whereabouts CNI plugin allows the dynamic assignment of an IP address to an additional network without the use of a DHCP server.

The Whereabouts CNI plugin also supports overlapping IP address ranges and configuration of the same CIDR range multiple times within separate NetworkAttachmentDefinition CRDs. This provides greater flexibility and management capabilities in multi-tenant environments.

Dynamic IP address configuration objects

The following table describes the configuration objects for dynamic IP address assignment with Whereabouts:

Table 6. ipam whereabouts configuration object
Field Type Description

type

string

The IPAM address type. The value whereabouts is required.

range

string

An IP address and range in CIDR notation. IP addresses are assigned from within this range of addresses.

exclude

array

Optional: A list of zero or more IP addresses and ranges in CIDR notation. IP addresses within an excluded address range are not assigned.

network_name

string

Optional: Helps ensure that each group or domain of pods gets its own set of IP addresses, even if they share the same range of IP addresses. Setting this field is important for keeping networks separate and organized, notably in multi-tenant environments.
Dynamic IP address assignment configuration that uses Whereabouts

The following example shows a dynamic address assignment configuration that uses Whereabouts:

Whereabouts dynamic IP address assignment

{
  "ipam": {
    "type": "whereabouts",
    "range": "192.0.2.192/27",
    "exclude": [
       "192.0.2.192/30",
       "192.0.2.196/32"
    ]
  }
}
Dynamic IP address assignment that uses Whereabouts with overlapping IP address ranges

The following example shows a dynamic IP address assignment that uses overlapping IP address ranges for multi-tenant networks.

NetworkAttachmentDefinition 1

{
  "ipam": {
    "type": "whereabouts",
    "range": "192.0.2.192/29",
    "network_name": "example_net_common", (1)
  }
}
1 Optional. If set, must match the network_name of NetworkAttachmentDefinition 2.
NetworkAttachmentDefinition 2

{
  "ipam": {
    "type": "whereabouts",
    "range": "192.0.2.192/24",
    "network_name": "example_net_common", (1)
  }
}
1 Optional. If set, must match the network_name of NetworkAttachmentDefinition 1.

Configuring SR-IOV additional network

You can configure an additional network that uses SR-IOV hardware by creating an SriovIBNetwork object. When you create an SriovIBNetwork object, the SR-IOV Network Operator automatically creates a NetworkAttachmentDefinition object.

Do not modify or delete an SriovIBNetwork object if it is attached to any pods in a running state.
Prerequisites

  • Install the OpenShift CLI (oc).

  • Log in as a user with cluster-admin privileges.

Procedure

  1. Create a SriovIBNetwork object, and then save the YAML in the <name>.yaml file, where <name> is a name for this additional network. The object specification might resemble the following example:

    apiVersion: sriovnetwork.openshift.io/v1
kind: SriovIBNetwork
metadata:
  name: attach1
  namespace: openshift-sriov-network-operator
spec:
  resourceName: net1
  networkNamespace: project2
  ipam: |-
    {
      "type": "host-local",
      "subnet": "10.56.217.0/24",
      "rangeStart": "10.56.217.171",
      "rangeEnd": "10.56.217.181",
      "gateway": "10.56.217.1"
    }

  2. To create the object, enter the following command:

    $ oc create -f <name>.yaml

    where <name> specifies the name of the additional network.

  3. Optional: To confirm that the NetworkAttachmentDefinition object that is associated with the SriovIBNetwork object that you created in the previous step exists, enter the following command. Replace <namespace> with the networkNamespace you specified in the SriovIBNetwork object.

    $ oc get net-attach-def -n <namespace>

Runtime configuration for an InfiniBand-based SR-IOV 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.

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

[
  {
    "name": "<network_attachment>", (1)
    "infiniband-guid": "<guid>", (2)
    "ips": ["<cidr_range>"] (3)
  }
]
1 The name of the SR-IOV network attachment definition CR.
2 The InfiniBand GUID for the SR-IOV device. To use this feature, you also must specify { "infinibandGUID": true } in the SriovIBNetwork object.
3 The 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 SriovIBNetwork object.
Example runtime configuration

apiVersion: v1
kind: Pod
metadata:
  name: sample-pod
  annotations:
    k8s.v1.cni.cncf.io/networks: |-
      [
        {
          "name": "ib1",
          "infiniband-guid": "c2:11:22:33:44:55:66:77",
          "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.

Prerequisites

  • Install the OpenShift CLI (oc).

  • Log in to the cluster.

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/network-status: |- (1)
      [{
          "name": "ovn-kubernetes",
          "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/network-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.

Exposing MTU for vfio-pci SR-IOV devices to pod

After adding a pod to an additional network, you can check that the MTU is available for the SR-IOV network.

Procedure

  1. Check that the pod annotation includes MTU by running the following command:

    $ oc describe pod example-pod

    The following example shows the sample output:

    "mac": "20:04:0f:f1:88:01",
       "mtu": 1500,
       "dns": {},
       "device-info": {
         "type": "pci",
         "version": "1.1.0",
         "pci": {
           "pci-address": "0000:86:01.3"
    }
  }

  2. Verify that the MTU is available in /etc/podnetinfo/ inside the pod by running the following command:

    $ oc exec example-pod -n sriov-tests -- cat /etc/podnetinfo/annotations | grep mtu

    The following example shows the sample output:

    k8s.v1.cni.cncf.io/network-status="[{
    \"name\": \"ovn-kubernetes\",
    \"interface\": \"eth0\",
    \"ips\": [
        \"10.131.0.67\"
    ],
    \"mac\": \"0a:58:0a:83:00:43\",
    \"default\": true,
    \"dns\": {}
    },{
    \"name\": \"sriov-tests/sriov-nic-1\",
    \"interface\": \"net1\",
    \"ips\": [
        \"192.168.10.1\"
    ],
    \"mac\": \"20:04:0f:f1:88:01\",
    \"mtu\": 1500,
    \"dns\": {},
    \"device-info\": {
        \"type\": \"pci\",
        \"version\": \"1.1.0\",
        \"pci\": {
            \"pci-address\": \"0000:86:01.3\"
        }
    }
    }]"

Additional resources