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.

note

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 OpenShift Virtualization do not conflict with other virtualization solutions on the same network.

Prerequisites

• You have cluster administrator access on an OpenShift Container Platform cluster.
• You have installed the OpenShift CLI (oc).

Procedure

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

   $ oc edit hyperconvergeds.v1beta1.hco.kubevirt.io kubevirt-hyperconverged -n openshift-cnv

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: "FE:A8:11:22:33:44"
   # ...

Verification

1. Run the following command and observe the output:

   $ oc get hyperconvergeds.v1beta1.hco.kubevirt.io kubevirt-hyperconverged -n openshift-cnv -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": "FE:A8:11:22:33:44"
   }

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.