Add Additional Subnets to Virtual Network Without Affecting its Existing Config

Question

Hi

I'm in a situation where I need to add additional subnets and NSG config to those subnets for an existing Virtual Network using Bicep. The existing Virtual Network and its subnet configuration was deployed in the past using mixed methods (ClickOps and some JSON ARM templates). My question is, can I reference the existing Virtual Network using the "existing" clause in Bicep and try to add new subnets to it without affecting / overwriting the existing subnets?

If not, what are my options in this case?

Thanks

Taranjeet Singh

Answer 1

@Taranjeet Malik ,

Welcome to the Microsoft Q&A Platform. Thank you for reaching out & I hope you are doing well.

I understand that you would like to deploy a subnet to an existing VNET using Bicep without disrupting the existing subnet configurations.

Yes, this is doable.

You can use the below bicep configuration example to achieve this.

var subnetName = 'newSubnet'
var vnetName = 'vnet'

resource myvnet 'Microsoft.Network/virtualNetworks@2023-04-01' existing = {
  name: vnetName
}

resource subnet 'Microsoft.Network/virtualNetworks/subnets@2023-04-01' = {

  name: subnetName
  parent: myvnet
  properties:{
    addressPrefix:'10.0.20.0/24' //Address prefix should **not** be overlapping with existing subnets
  }

}

Thanks,

Kapil

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