[BUG] Enabled Istio mesh on preexisting cluster but no actual Istio resources present

[benjaminxie]

Describe the bug
I am trying to enable the mesh add-on on a preexisting cluster and am following the instructions at https://learn.microsoft.com/en-us/azure/aks/istio-deploy-addon. I got rid of my previous Istio deployment (I deployed the helm charts myself) and the namespaces are deleted too. However, after the az CLI command is run and despite serviceMeshProfile.mode showing as Istio, I see no aks-istio-system namespace and definitely no Istio-related pods.

To Reproduce
Steps to reproduce the behavior:

1. Set up RESOURCE_GROUP and CLUSTER environment variables
2. Run command az aks mesh enable --resource-group ${RESOURCE_GROUP} --name ${CLUSTER}
3. Run command az aks show --resource-group ${RESOURCE_GROUP} --name ${CLUSTER} --query 'serviceMeshProfile.mode' and see output Istio
4. Run command kubectl get ns aks-istio-system and get error that there is no aks-istio-system namespace

Expected behavior
I expect to see the aks-istio-system namespace and the related pods.

Environment (please complete the following information):

• CLI Version 2.61.0
• Kubernetes version 1.30.5

Additional context
I have also "successfully" upgraded from Istio 1.22 to 1.23 via the web portal but my cluster still lacks any Istio-related resources.

I doubt my reproduction steps will actually lead to someone reproducing my issue and I assume I'm just doing something wrong but I am following the steps and cannot find any logging that points to any issues. I have also run the az aks mesh enable command with the debug flag and also failed to find any clues in the extra output.

[Winbobob]

There are two options that could help root cause this issue:

• Option1: create a new AKS cluster and enable addon to see if it works. If so, there could be some components in your existing cluster that prevent istio addon to be installed properly like CRDs, charts.
• Option2: create a support ticket then we could check the cluster for you.

[biefy]

@benjaminxie how did you uninstall the previous installation? Have you deleted all CRDs?

[microsoft-github-policy-service]

@azure/aks-traffic would you be able to assist?