monitoring

KubeMacPoolDuplicateMacsFound

Meaning

This alert fires when KubeMacPool detects duplicate MAC addresses.

KubeMacPool is responsible for allocating MAC addresses and preventing MAC address conflicts. When KubeMacPool starts, it scans the cluster for the MAC addresses of virtual machines (VMs) in managed namespaces.

Impact

Duplicate MAC addresses on the same LAN might cause network issues.

Diagnosis

1. Obtain the namespace and the name of the kubemacpool-mac-controller pod:

   $ kubectl get pod -A -l control-plane=mac-controller-manager --no-headers \
      -o custom-columns=":metadata.namespace,:metadata.name"
   

2. Obtain the duplicate MAC addresses from the kubemacpool-mac-controller logs:

   $ kubectl logs -n <namespace> <kubemacpool_mac_controller> | grep "already allocated"
   

   Example output:

   mac address 02:00:ff:ff:ff:ff already allocated to vm/kubemacpool-test/testvm, br1, 
   conflict with: vm/kubemacpool-test/testvm2, br1
   

Mitigation

1. Update the VMs to remove the duplicate MAC addresses.

2. Restart the kubemacpool-mac-controller pod:

   $ kubectl delete pod -n <namespace> <kubemacpool_mac_controller>