updatingVnetDns.json

{
  "$schema": "http://schema.management.azure.com/schemas/2015-01-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "vnetName": {
      "type": "string",
      "metadata": {
        "description": "Specifies the name of the virtual network whose DNS settings are to be updated."
      }
    },
    "vnetAddressRange": {
      "type": "string",
      "metadata": {
        "description": "Specifies the address range of the entire virtual network."
      }
    },
    "subnetName": {
      "type": "string",
      "metadata": {
        "description": "Specifies the name of the subnet within the virtual network."
      }
    },
    "subnetAddressRange": {
      "type": "string",
      "metadata": {
        "description": "Specifies the address range of the subnet within the virtual network."
      }
    },
    "location": {
      "type": "string",
      "defaultValue": "[resourcegroup().location]",
      "metadata": {
        "description": "Specifies the Location for the deployment."
      }
    },
    "dnsServers": {
      "type": "array",
      "metadata": {
        "description": "Specifies the DNS servers the virtual network should use for its DNS settings."
      }
    }
  },
  "resources": [
    {
      "apiVersion": "2015-06-15",
      "name": "virtualNetwork",
      "type": "Microsoft.Network/virtualNetworks",
      "tags": {
        "displayName": "VirtualNetwork"
      },
      "location": "[parameters('location')]",
      "properties": {
        "addressSpace": {
          "addressPrefixes": [
            "[parameters('vnetAddressRange')]"
          ]
        },
        "dhcpOptions": {
          "dnsServers": "[parameters('dnsServers')]"
        },
        "subnets": [
          {
            "name": "[parameters('subnetName')]",
            "properties": {
              "addressPrefix": "[parameters('subnetAddressRange')]"
            }
          }
        ]
      }
    }
  ]
}