With the support for configurable network interfaces, user should be able to create multiple subnets for a control-plane node

[nawazkh]

/kind bug

[Before submitting an issue, have you checked the Troubleshooting Guide?]

What steps did you take and what happened:
[A clear and concise description of what the bug is.]

• While testing Azure CNI v1 with the below AzureCluster template, the resource AzureCluster does not get created with the error The AzureCluster "azure-cni-v1-25064" is invalid: spec.networkSpec.subnets[3]: Duplicate value: map[string]interface {}{"name":"cp-subnet-1"}

apiVersion: infrastructure.cluster.x-k8s.io/v1beta1
kind: AzureCluster
metadata:
  name: ${CLUSTER_NAME}
  namespace: default
spec:
  identityRef:
    apiVersion: infrastructure.cluster.x-k8s.io/v1beta1
    kind: AzureClusterIdentity
    name: ${CLUSTER_IDENTITY_NAME}
  location: ${AZURE_LOCATION}
  networkSpec:
    subnets:
    - name: node-subnet-1
      role: node
    - name: node-subnet-2
      role: node
    - name: cp-subnet-1
      role: control-plane
    - name: cp-subnet-2
      role: control-plane
    vnet:
      name: ${AZURE_VNET_NAME:=${CLUSTER_NAME}-vnet}
  resourceGroup: ${AZURE_RESOURCE_GROUP:=${CLUSTER_NAME}}
  subscriptionID: ${AZURE_SUBSCRIPTION_ID}

• This happens because of two reasons
  • Primarily : At https://github.com/kubernetes-sigs/cluster-api-provider-azure/blob/de72779812a86c2cda550f07cfbbc31e76547432/api/v1alpha3/types.go#L459 , we assume that there would only be one control-plane subnet.
  • Secondly: While setting defaults, we update all the role: control-plane subnets with the one we found above.
• This results in the error we see while creating AzureCluster resource with multiple subnets of type role: control-plane

What did you expect to happen:

• User should be able to create multiple subnets with of the type role: control-plane for control-plane nodes.

Anything else you would like to add:
[Miscellaneous information that will assist in solving the issue.]

Environment:

• cluster-api-provider-azure version: v1.8.3
• Kubernetes version: (use kubectl version): v1.25.9
• OS (e.g. from /etc/os-release):

[mboersma]

/priority important-longterm

[k8s-triage-robot]

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/lifecycle stale

[nawazkh]

/remove-lifecycle stale

[k8s-triage-robot]

The Kubernetes project currently lacks enough contributors to adequately respond to all issues.

This bot triages un-triaged issues according to the following rules:

• After 90d of inactivity, lifecycle/stale is applied
• After 30d of inactivity since lifecycle/stale was applied, lifecycle/rotten is applied
• After 30d of inactivity since lifecycle/rotten was applied, the issue is closed

You can:

• Mark this issue as fresh with /remove-lifecycle stale
• Close this issue with /close
• Offer to help out with Issue Triage

Please send feedback to sig-contributor-experience at kubernetes/community.

/lifecycle stale

[k8s-triage-robot]

The Kubernetes project currently lacks enough active contributors to adequately respond to all issues.

This bot triages un-triaged issues according to the following rules:

• After 90d of inactivity, lifecycle/stale is applied
• After 30d of inactivity since lifecycle/stale was applied, lifecycle/rotten is applied
• After 30d of inactivity since lifecycle/rotten was applied, the issue is closed

You can:

• Mark this issue as fresh with /remove-lifecycle rotten
• Close this issue with /close
• Offer to help out with Issue Triage

Please send feedback to sig-contributor-experience at kubernetes/community.

/lifecycle rotten