Known issues with the AKS engine on Azure Stack Hub

This topic covers known issues for the AKS engine on Azure Stack Hub.

Unable to resize cluster VMs with the Compute service

  • Applicable to: Azure Stack Hub, AKS engine (all)
  • Description: Resizing cluster VMs through the Compute service doesn't work with AKS engine. The AKS engine maintains the state of the cluster in the API model json file. To ensure that the desired VM size is reflected in any create, update, or scale operation done with AKS engine you must update the API model before executing any of those operations. For example, if you change a VM size on an already deployed cluster to a different size using the Compute service, the state will be lost when aks-engine update is executed.
  • Remediation: To make this work locate the API model for the cluster, change the size there, and then run aks-engine update.
  • Occurrence: When attempting to resize using the Compute service.

Disk detach operation fails in AKS engine 0.55.0

  • Applicable to: Azure Stack Hub (update 2005), AKS engine 0.55.0
  • Description: When you try to delete a deployment that contains persistence volumes, the delete operation triggers a series of attach/detach errors. This is due to a bug in the AKS engine v0.55.0 Cloud Provider. The Cloud Provider calls the Azure Resource Manager using a newer version of the API than the Azure Resource Manager currently supports in Azure Stack Hub (update 2005).
  • Remediation: You can find the details and mitigation steps in the AKS engine GitHub repository (Issue 3817). Upgrade as soon as a new build of AKS engine and corresponding image are available.
  • Occurrence: When deleting a deployment that contains persistence volumes.

Upgrade issues in AKS engine 0.51.0

  • During upgrade (aks-engine upgrade) of a Kubernetes cluster from version 1.15.x to 1.16.x, upgrade of the following kubernetes components requires extra manual steps: kube-proxy, azure-cni-networkmonitor, csi-secrets-store, kubernetes-dashboard. The following describes what you may observe and how to work around the issues.

    • In connected environments, it is not obvious to notice this issue since there are no signs in the cluster that the affected components were not upgraded. Everything appears to work as expected.
    kubectl get pods -n kube-system
    
    • As a workaround to solve this issue for each of these components, run the command in the Workaround column in the following table.

      Component Name Workaround Affected Scenarios
      kube-proxy kubectl delete ds kube-proxy -n kube-system Connected, Disconnected
      azure-cni-networkmonitor kubectl delete ds azure-cni-networkmonitor -n kube-system Connected, Disconnected
      csi-secrets-store sudo sed -i s/Always/IfNotPresent/g /etc/kubernetes/addons/secrets-store-csi-driver.yaml
      kubectl delete ds csi-secrets-store -n kube-system
      Disconnected
      kubernetes-dashboard Run the following command on each master node:
      sudo sed -i s/Always/IfNotPresent/g /etc/kubernetes/addons/kubernetes-dashboard.yaml
      Disconnected
  • Kubernetes 1.17 is not supported in this release. Although there are GitHub pull requests (PR)s referencing 1.17, it is not supported.

aks-engine get-versions command limitations

The output of the aks-engine get-versions command only relates to global Azure rather than Azure Stack Hub. For more information about the various upgrade paths, see Steps to upgrade to a newer Kubernetes version.

Next steps

AKS engine on Azure Stack Hub overview