azurerm_kubernetes_cluster - support for the default_node_pool.snapshot_id property

[ms-henglu]

fixes #22656

=== RUN   TestAccKubernetesCluster_snapshotId
=== PAUSE TestAccKubernetesCluster_snapshotId
=== CONT  TestAccKubernetesCluster_snapshotId
--- PASS: TestAccKubernetesCluster_snapshotId (1593.10s)
PASS

[js-315385995]

Does it support a rolling update? Or will the node pool be recreated on snapshot_id change?

[ms-henglu]

Hi @js-315385995 , yes, it could be updated, but it is done by cycling the system node pool of the cluster, temporary_name_for_rotation must be specified when changing it. I've updated the doc as well.

[zioproto]

I tested like this:

1. Take snapshot of system nodepool from an existing AKS cluster:

NODEPOOL_ID=$(az aks nodepool show -g istio-aks --cluster-name istio-aks -n system --query id -o tsv)
az group create --name snapshots --location eastus
az aks nodepool snapshot create --name systemsnap --resource-group snapshots --nodepool-id $NODEPOOL_ID --location eastus

2. Get the ID of the new snapshot:

az aks nodepool snapshot show --name systemsnap --resource-group snapshots --query id -o tsv

3. Run the following Terraform:

resource "azurerm_kubernetes_cluster" "aks" {
  name                = "aktest"
  location            = "eastus"
  resource_group_name = "istio-aks"
  dns_prefix          = "aks"
  kubernetes_version  = "1.25.11"
  identity {
    type = "SystemAssigned"
  }
  default_node_pool {
    name                = "default"
    node_count          = 1
    vm_size             = "Standard_DS3_v2"
    type                = "VirtualMachineScaleSets"
    enable_auto_scaling = true
    max_count           = 3
    min_count           = 1
    os_disk_size_gb     = 30
    snapshot_id =  "/subscriptions/<subscription_id_redacted>/resourceGroups/snapshots/providers/Microsoft.ContainerService/snapshots/systemsnap"
  }
}

provider "azurerm" {
  features {}
}

It created the cluster as expected.

@ms-henglu @stephybun is there anything else we can test ? What is missing to get this merged ?

thanks

[stephybun]

We should parse this ID insensitively before setting it to state

[ms-henglu]

Thanks! I've updated it.

[stephybun]

Thanks @ms-henglu LGTM 💯

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