AKS clusters using kubenet networking — migrate to Azure CNI Overlay before Mar 31, 2028

AzureDeprecations & retirementsTeam planSeverity: mediumazure.aks

AKS clusters using kubenet networking, which is retired on March 31, 2028; migrate to Azure CNI Overlay

What LeftSize checks

Find AKS clusters using kubenet networking.

Why it matters

Missed retirement and end-of-support dates turn into forced upgrades, outages or extended support charges at a moment you did not choose.

What you get in the GitHub issue

LeftSize runs this check from a scheduled GitHub Action with a read-only identity in your Azure account and opens one issue per scope, updated on every scan. The issue includes:

  • The affected resources, grouped per subscription, resource group or account and region
  • Background on why it was flagged and when it is a false positive
  • Cost and operational impact of fixing it
  • Alternative approaches and their trade-offs
  • Step-by-step remediation with safety checks
  • Ready-to-run fix scripts (CLI, PowerShell or Terraform where available)
  • Snooze, ignore or report a finding with a comment on the issue
Install LeftSizeIncluded in the Team and Business plans.

Official references