Virtual network bicep script unable to add subnet delegation for services

Question

I have got the code base which can be found on https://github.com/jake7745/bicep-vnet with the initial work by github@ChristopherGLewis.

The code works well by creating a virtual network, and subnets the difficulty here is that one cannot add service delegation to the subnets.

param vNetName string
param rgVnet string
param subnetName string
param subnetAddressPrefix string
param delegations array = []

//Subnet with delegation
resource subnet 'Microsoft.Network/virtualNetworks/subnets@2020-06-01' = {
  name: '${vNetName}/${subnetName}'
  properties: { 
    // delegations: delegations
    delegations:[
      {
        name: 'delegation'
        properties:{
          serviceName: 'Microsoft.Web/serverfarms'
        }
      }
    ]
  }
}

The code above is how a service delegation will be added, however I just cannot get it to work. The vnet and subnets are created, but without the delegation.

Any help or insight here would be appreciated.

Answer 1

Try setting the delegation name differently.

This code works;

param location string = resourceGroup().location
param vNetName string = 'vnetGord'
param vNetAddressPrefix string = '10.0.0.0/16'
param subnetAddressPrefix string= '10.0.1.0/24'

resource vnet 'Microsoft.Network/virtualNetworks@2022-11-01' = {
  name: vNetName
  location: location
  properties: {
    addressSpace: {
      addressPrefixes: [vNetAddressPrefix]
    }
  }
}

resource serverFarmSubnet 'Microsoft.Network/virtualNetworks/subnets@2020-06-01' = {
  name: 'aSubnet'
  parent: vnet
  properties: { 
    addressPrefix: subnetAddressPrefix
    delegations: [
      {
        name: 'Microsoft.Web/serverfarms'
        properties: {
          serviceName: 'Microsoft.Web/serverfarms'
        }
      }
    ]
  }
}

Answer 2

Hi,

There is one particular issue with this resource - subnets. They should be created within Microsoft.Network/virtualNetworks resource rather as separate resource as Microsoft.Network/virtualNetworks/subnets. There is quite a big discussion here. You can check examples on how to deploy the subnet with the virtual network resource here

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