Get Azure VM's NSG Using Powershell CLI

Question

The task is to modify an Azure Network Security Group Rule.

I am all OK there (using az network nsg rule update ), provided the name of the NSG and the actual Rule.

But what I want to do is edit that rule with the VM Name (subscription ID, RG name and Rule name are already known and will be explicit) as the input parameter.

I am using az (not Az) commands.

What I see is az vm show, but it doesn't show which NSG the VM is connected to.

I would like to ask how to get the NSG name where a VM is associated, using CLI. Straight answers, guides or links to resources will all be appreciated.

Thank you and thanks in advance!

Answer 1

Follow the Microsoft documentation below

https://docs.microsoft.com/en-us/powershell/module/az.network/get-aznetworksecuritygroup?view=azps-6.5.0

Get-AzNetworkSecurityGroup [-Name <String>][-ResourceGroupName<String> [-DefaultProfile <IAzureContextContainer>][<CommonParameters>]

Answer 2

You would also need to provide the Resource Group in which the VM is located - this is how it will be able to differentiate between two VM with same name in different Resource Groups. Here, {id:id} creates a map that can be used with the subsequent commands. There are other ways to do this but I prefer this approach since I'm more familiar with the format.

Here's what you could do:

1. Using the VM name and RG, get the VM's NIC's ID and save it to nic_id :

vm_name="myvm"
vm_rg="myrg"
nic_id=`az vm nic list -g $vm_rg --vm-name $vm_name --query "[].{id:id}"`
# echo to make sure we're getting the right value. 
echo $nic_id

2. Using the NIC ID, get the Subnet ID

snet_id=`az network nic show --ids $nic_id --query "ipConfigurations[0].subnet.{id:id}"`
# echo to make sure we're getting the right value. 
echo $snet_id

3. Finally, using the Subnet ID, get the NSG's name

nsg_name=`az network vnet subnet show --ids $snet_id --query networkSecurityGroup.{id:id} -o tsv | sed 's/^.*networkSecurityGroups\///'`
# echo to make sure we're getting the right value. 
echo $nsg_name