Two AKS on the same subnet using Azure CNI plugin

Question

Is there any problem with the deployment of two AKS clusters using Azure CNI plugin in the same subnet besides the possibility of IP address pool exhaustion? The documentation https://learn.microsoft.com/en-us/azure/aks/operator-best-practices-network says not to do this but it is not clear to me why and if it is really related to Azure CNI networks or just to kubenet networks.

Answer 1

Hi @Savva, Thanks for reaching out and I hope you are doing well. Based on our documentation, the recommendation of not deploying two AKS clusters in the same subnet applies to kubenet only: https://learn.microsoft.com/en-us/azure/aks/configure-kubenet#prerequisites But it does not apply to Azure CNI as you can see: https://learn.microsoft.com/en-us/azure/aks/configure-azure-cni#prerequisites The main reason we don't recommend having two AKS clusters in the same subnet if using kubenet is described in the following GitHub link: https://github.com/MicrosoftDocs/azure-docs/issues/37462 As you clearly mentioned, having two AKS clusters sharing the same subnet can lead to IP addresses exhaustion quickly. Please "Accept the answer" if the information helped you. This will help us and others in the community as well. Feel free to reply with any other questions or concerns. Hope this helps!