Nested variable and resource with copy not working - azure

Question

I am trying to use nested resources with copy option as mentioned in https://learn.microsoft.com/en-us/azure/azure-resource-manager/resource-group-create-multiple#serial-copy
I have defined "lbApiVersion" inside nested resource variable block but some how the nested variable block is not recognize.
below is the ARM template i am trying and this is just example in actual scenario i want to pass array to arm template and then create multiple group of resources in loop, so in that case i need the nested variable block.
ARM -
{
"$schema": "https://schema.management.azure.com/schemas/2015-01-01/deploymentTemplate.json#",
"contentVersion": "1.0.0.0",
"parameters": {
"numberToDeploy": {
"type": "int",
"minValue": 2,
"defaultValue": 2
}
},
"resources": [
{
"apiVersion": "2015-01-01",
"type": "Microsoft.Resources/deployments",
"name": "[concat('loop-', copyIndex())]",
"copy": {
"name": "iterator",
"count": "[parameters('numberToDeploy')]",
"mode": "serial",
"batchSize": 1
},
"properties": {
"mode": "Incremental",
"template": {
"$schema": "http://schema.management.azure.com/schemas/2015-01-01/deploymentTemplate.json#",
"contentVersion": "1.0.0.0",
"parameters": {},
"variables": {
"lbApiVersion": "2015-06-15"
},
"resources": [
{
"apiVersion": "[variables('lbApiVersion')]",
"type": "Microsoft.Network/loadBalancers",
"name": "[concat('LB','-', copyIndex())]",
"location": "[parameters('clusterLocation')]",
"dependsOn": [
],
"properties": {
"frontendIPConfigurations": [
],
"backendAddressPools": [
],
"loadBalancingRules": [
],
"probes": [
],
"inboundNatPools": [
]
},
"tags": {
"resourceType": "Service Fabric"
}
}
],
"outputs": {
}
}
}
}
],
"outputs": {
}
}
"message": "Unable to process template language expressions for resource '/subscriptions/*************/resourceGroups/cluv2/providers/Microsoft.Resources/deployments/loop-0' at line '14' and column '10'. 'The template
variable 'lbApiVersion' is not found.

Answer 1

Based on my experience, when you define nested templates inline (so in the code of your existing template) they take parameter and variable values from your parent template, so just move the variable definition to your parent template

Answer 2

Unfortunately, you are not able to use variables and parameters in nested templates as indicated by the documentation. You can use them in external templates.
If you are trying to deploy multiple resources in an inline template, declare a variable or parameter of type object in the main template like this:
"variables" : {
"loadBalancers": [
{
"version": "2015-06-15"
},
{
"version": "2015-06-15"
}
]
}
Your copy on the Microsoft.Resources/deployments resource will look like this:
"copy": {
"name": "loadBalancerLoop",
"count": "[length(variables('loadBalancers'))]"
}
Then, in your nested resource, use the copyIndex() to grab the version
"apiVersion": "[variables('loadBalancers')[copyIndex()].version]"