ReadLoadBalancerIp

{
    "$schema": "http://schema.management.azure.com/schemas/2015-01-01/deploymentTemplate.json",
    "contentVersion": "1.0.0.0",
    "parameters": {
        "loadBalancer" : {
            "type": "string"
        }
    },
    "variables": {
    },
    "resources": [
    ],
    "outputs": {
        "IpAddress": {
            "type": "string",
            "value": "[reference(resourceId('Microsoft.Network/loadBalancers', parameters('loadBalancer')), '2015-06-15').frontendIPConfigurations[0].properties.privateIPAddress]"
        }
    }
}