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Intermittent connectivity issues with MetalLB or Kubernetes services of type Load Balancer

You might sometimes experience intermittent connectivity issues when accessing a Kubernetes service of type LoadBalancer using the assigned external IP address. This article describes how to identify and resolve connection issues with MetalLB or Kubernetes services of type LoadBalancer.

Symptoms

  • The service is accessible sometimes, but not consistently.

  • The client experiences unexpected disconnects.

  • The external IP intermittently appears and disappears from the control plane when running Get-VMNetworkAdapter:

    Get-VMNetworkAdapter -VMName * | select name, ipaddresses 

...

# The external IP appears in the get-vmnetworkadapter output 

nocpip26-55bc418a-control-plane-kjqcm-nic-b607b1e0                         
{172.16.0.11, 172.16.0.10, ***172.16.100.0***, fe80::ec:d3ff:fe8b:1} 

# Now it's gone 

Get-VMNetworkAdapter -VMName * | select name, ipaddresses 

...

nocpip26-55bc418a-control-plane-kjqcm-nic-b607b1e0                         
{172.16.0.11, 172.16.0.10, ***Now it is gone*** fe80::ec:d3ff:fe8b:1} 

# Now it's back 

Get-VMNetworkAdapter -VMName * | select name, ipaddresses

... 

nocpip26-55bc418a-control-plane-kjqcm-nic-b607b1e0                         
{172.16.0.11, 172.16.0.10, ***172.16.100.0***, fe80::ec:d3ff:fe8b:1}

Mitigation

This issue was fixed in AKS on Azure Local, version 2411.

If you're on an older build, please update to Azure Local, version 2411. Once you update to 2411, you can:

  • Create a new AKS cluster. The new AKS cluster should not have any intermittent load balancer connectivity issues.
  • Upgrade the Kubernetes version of your existing AKS cluster to get the fix.

Next steps

Troubleshoot issues in AKS enabled by Azure Arc