fix: process imported_config outside switch

[krunalhinguu]

Issue

• [BUG] importedConfig.privateRegistryURL is not applied to an existing imported hosted cluster (AKS) #1637

Problem

Currently, the imported_config block is only processed when the driver is explicitly set to "imported".
This causes updates to fail or silently ignore imported_config settings (e.g., private_registry_url) for hosted imported clusters, since they use their respective driver blocks (aks_config_v2, eks_config_v2, gke_config_v2) instead of the "imported" driver.

Solution

The handling of imported_config has been pulled out of the driver switch block and is now applied independently of driver type.
This ensures imported_config is always processed when defined, including for hosted imported clusters during updates.

Testing

• Import an existing AKS/EKS/GKE cluster into Rancher using Terraform.
• Apply an update that adds an imported_config block (e.g., setting private_registry_url).
• Confirm that the update succeeds and the imported config is applied in Rancher.
• Validate that clusters without imported_config remain unaffected.

Engineering Testing

Manual Testing

• Imported an AKS cluster (aks_config_v2 with imported = true) into Rancher.
• Applied an update with imported_config defined and verified the changes were applied correctly.
• Imported an EKS cluster and repeated the above validation.
• Confirmed that "imported" driver clusters still accept imported_config.

Automated Testing

• No automated tests added at this stage.
• Regression risk is limited to update handling for clusters with imported_config.

QA Testing Considerations

• Import AKS/EKS/GKE clusters into Rancher, then update them with imported_config to ensure changes apply.
• Validate that "imported" driver clusters continue to work.
• Ensure updates to non-imported hosted clusters (AKS/EKS/GKE without imported_config) succeed without errors.

Regressions Considerations

• Regression risk: updates to "imported" driver clusters.
• Probability: low, as logic was only refactored to run before driver-specific handling.

[mjura]

I am not sure, if we are mixing here settings. For hosted providers imported flag is set inside hosted_provider_spec, e.g. https://github.com/rancher/aks-operator/blob/main/pkg/apis/aks.cattle.io/v1/types.go#L43

Even if hosted provider imported cluster is set, then it should be managed by hoster provider operator

[krunalhinguu]

We got this example from customer

So do you mean that this is incorrect way of initialising it? And it should be inside the aks_config_v2?

resource "rancher2_cluster" "aks_imported" {
  name        = var.aks_cluster_name
  description = "Imported AKS cluster via Terraform"
  aks_config_v2 {
    cloud_credential_id = rancher2_cloud_credential.aks.id
    resource_group      = var.resource_group_name
    resource_location   = var.azure_location
    imported            = true
  }
  imported_config {
      private_registry_url = "registry.suse.com"
  }
}

[mjura]

sorry, it looks good to me, I had to understand bug description 👍

[matttrach]

This looks good from a general Terraform point of view, but we still need approval from the responsible team to merge.

[mjura]

sorry, it looks good to me, I had to understand bug description 👍