---
title: Managing MAC address pools for network interfaces
---

# Managing MAC address pools for network interfaces {#virt-using-mac-address-pool-for-vms}

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 {#virt-managing-kubemacpool-cli_virt-using-mac-address-pool-for-vms}

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:

  ```terminal
  $ oc label namespace <namespace1> <namespace2> mutatevirtualmachines.kubemacpool.io=ignore
  ```
- To re-enable KubeMacPool in two namespaces, run the following command:

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

## Customizing the MAC pool range {#virt-custom-kubemacpool-range_virt-using-mac-address-pool-for-vms}

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:

   ```terminal
   $ 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:

   ```yaml
   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:

   ```terminal
   $ 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:

   ```terminal
   {
     "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:

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

   Example output:

   ```yaml
   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`.