To facilitate the management of Nvidia BlueField-2 DPU, a two-cluster design is being proposed. Under such design, a BlueField-2 card will be provisioned as a worker node of the ARM-based infra cluster, whereas the tenant cluster where the normal user applications run on, is composed of the X86 servers.

The OVN-Kubernetes components are spread over the two clusters. On the tenant cluster side, the Cluster Network Operator is in charge of the management of the ovn-kube components. On the infra cluster side, we propose to create a new operator to be responsible for the life-cycle management of the ovn-kube components and the necessary host network initialization on DPU cards.

• An tenant openshift cluster is composed of X86 hosts. The BlueField-2 cards are installed on the worker nodes where hardware offloading need to be enabled
• An infra Openshift cluster is composed of ARM hosts. The BlueField-2 cards are provisioned as worker nodes of the cluster.
• Pods in infra cluster can reach the API server of tenant cluster

This is designed to run as pod of in the infra cluster. However, we can run it locally for development purpose.

1. Choose a local namespace where the ovnkube components shall be provisioned.

2. Store the kubeconfig file of the tenant cluster in a Secret

   $ kubectl create secret generic tenant-cluster-1-kubeconf --from-file=config=/root/manifests/kubeconfig.tenant

3. Create a ConfigMap to store the node specific environment variables.

   Example:

   kind: ConfigMap
   apiVersion: v1
   metadata:
   name: env-overrides
   namespace: default
   data:
   bf2-worker-advnetlab13: |
       TENANT_K8S_NODE=worker-advnetlab13
       DPU_IP=192.168.111.57
       MGMT_IFNAME=eth3

   • bf2-worker-advnetlab13 is the name of the DPU node.
   • TENANT_K8S_NODE is the x86 node name where the DPU is installed.
   • DPU_IP is the IP address of the DPU node in the tenant node network.
   • MGMT_IFNAME the VF representor name which is used for the ovn-k8s-mp0.

4. Start the operator

   $ TENANT_NAMESPACE=openshift-ovn-kubernetes NAMESPACE=default make run

   • TENANT_NAMESPACE specifies the namespace where the ovnkube is running in the tenant cluster.
   • NAMESPACE specifies the local namespace where the ovnkube components shall be deployed.

5. Create an ovnkubeconfig custom resource Example:

   apiVersion: dpu.openshift.io/v1alpha1
   kind: OVNKubeConfig
   metadata:
   name: ovnkubeconfig-sample
   namespace: default
   spec:
   kubeConfigFile: tenant-cluster-1-kubeconf
   poolName: dpu
   nodeSelector:
     matchLabels:
       node-role.kubernetes.io/dpu-worker: ""

   1. kubeConfigFile stores the secret name of the tenant cluster kubeconfig file. The operator uses this to access the api-server of the tenant cluster.
   2. poolName specifies the name of the MachineConfigPool CR which contains all the BF2 nodes in the infra cluster.
   3. nodeSelector The operator copies it to the spec.nodeSelector of MCP.

NOTE: By default, the operator will use the ovnkube image of the infra cluster when generating the ovnkube-node DaemonSet. You can also use environment variable OVNKUBE_IMAGE to specify a particular image you want to use.