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Managing MAC address pools for network interfaces

KubeMacPool allocates MAC addresses for virtual machine (VM) network interfaces from a shared MAC address pool. This ensures that each network interface is assigned a unique MAC address.

A virtual machine instance created from that VM retains the assigned MAC address across reboots.

KubeMacPool does not handle virtual machine instances created independently from a virtual machine.

Managing KubeMacPool by using the CLI

You can disable and re-enable KubeMacPool by using the command line.

KubeMacPool is enabled by default.

Prerequisites

  • You have installed the OpenShift CLI (oc).

Procedure

  • To disable KubeMacPool in two namespaces, run the following command:

    $ oc label namespace <namespace1> <namespace2> mutatevirtualmachines.kubemacpool.io=ignore

  • To re-enable KubeMacPool in two namespaces, run the following command:

    $ oc label namespace <namespace1> <namespace2> mutatevirtualmachines.kubemacpool.io-

Customizing the MAC pool range

KubeMacPool works by allocating MAC addresses to VMs from a range. The rangeStart and rangeEnd parameters in the HyperConverged custom resource (CR) define the MAC pool range.

As a cluster administrator, you can configure this range to ensure that MAC addresses for VMs hosted on OKD Virtualization do not conflict with other virtualization solutions on the same network.

Prerequisites

  • You have cluster administrator access on an OKD cluster.

  • You have installed the OpenShift CLI (oc).

Procedure

  1. Edit the HyperConverged CR by running the following command:

    $ oc edit hyperconverged kubevirt-hyperconverged -n kubevirt-hyperconverged

  2. Update the HyperConverged CR to configure the rangeStart and rangeEnd parameters that define your required MAC address range:

    apiVersion: hco.kubevirt.io/v1beta1
kind: HyperConverged
metadata:
  name: kubevirt-hyperconverged
spec:
  kubeMacPoolConfiguration:
    rangeStart: "AA:00:00:00:00:00"
    rangeEnd: "FD:FF:FF:FF:FF:FF"
# ...
Verification

  1. Run the following command and observe the output:

    $ oc get hco kubevirt-hyperconverged -n kubevirt-hyperconverged -o=jsonpath='{.spec.kubeMacPoolConfiguration}'

    If you have successfully applied the configuration changes, the output shows the new MAC pool range you have configured:

    Example output:

    {
  "rangeStart": "AA:00:00:00:00:00",
  "rangeEnd": "FD:FF:FF:FF:FF:FF"
}

  2. Optional. Create a new VM and run the following command to check the MAC address of the VM’s network interface:

    $ oc get vmi <vm-name> -o=jsonpath='{.status.interfaces[0].macAddress}'

    Example output:

    macAddress: AA:00:00:00:00:04

    If you have successfully applied the configuration changes, the macAddress field in the VM interface is within the range you specified in your kubeMacPoolConfiguration, between the value of rangeStart and rangeEnd.