terraform templatefile Function Invalid template interpolation value(AKS Cluster Name) - terraform

Question

I try to provision an azure dashboard using terraform module and template file but I get an error message:
Call to function "templatefile" failed:
src/main/terraform/environment/modules/someservice/resources/dashboards/infrastructure-dashboard.tpl:41,39-55:
Invalid template interpolation value; Cannot include the given value in a
string template: string required., and 25 other diagnostic(s).
The error is being caused by the code in the template. It does not accept the variable declared in the dashboard properties. The code in the template causing the error:
"clusterName": "${k8s_cluster_name}",
Terraform code:
resource "azurerm_dashboard" "infra-dashboard" {
name = "${upper(terraform.workspace)}-Infrastructure"
resource_group_name = azurerm_resource_group.rgp-dashboards.name
location = azurerm_resource_group.rgp-dashboards.location
tags = {
source = "terraform"
}
dashboard_properties = templatefile("${path.module}/resources/dashboards/infrastructure-dashboard.tpl",
{
md_content = var.infra_dashboard_md_content,
dashboard_title = var.infra_dashboard_title,
dashboard_subtitle = var.infra_dashboard_subtitle,
sub_id = data.azurerm_subscription.current.subscription_id,
rgp_k8s = azurerm_resource_group.seervice-k8s.name,
k8s_cluster_name = azurerm_kubernetes_cluster.service-k8s.*.name,
rgp_service_env_global_name = azurerm_resource_group.service-env-global.name,
log_analyt_wrkspc = local.log_analyt_wrkspc
})
}
Snippet from the tmeplate where the error occurs:
"1": {
"position": {
"x": 0,
"y": 4,
"colSpan": 9,
"rowSpan": 4
},
"metadata": {
"inputs": [
{
"name": "queryParams",
"value": {
"metricQueryId": "node-count",
"clusterName": "${k8s_cluster_name}",
"clusterResourceId": "/subscriptions/${sub_id}/resourceGroups/${rgp_k8s}/providers/Microsoft.ContainerService/managedClusters/${k8s_cluster_name}",
"workspaceResourceId": "/subscriptions/${sub_id}/resourcegroups/${rgp_service_env_global_name}/providers/microsoft.operationalinsights/workspaces/${log_analyt_wrkspc}",
"timeRange": {
"options": {},
"relative": {
"duration": 21600000
}
},
"cpuFilterSelection": "total",
"memoryFilterSelection": "total_memoryrss"
}
}

Answer 1

For example:
join(",", azurerm_kubernetes_cluster.service-k8s.*.name)
will join all entries with an ",". Replace it with whatever you need

Answer 2

As luk2302 said azurerm_kubernetes_cluster.service-k8s.*.name it is not a string. In fact it is a tuple