Azure Databricks deployment- unable to create Private Subnet CIDR Range

Question

In Azure, I have a virtual network (vNET) with following settings:

 Address space: 10.200.0.0/20
 subnet: 10.200.0.0/24

Inside the above vNET, I am trying to deploy an Azure Databricks with the following Network settings:

Public Subnet CIDR Range: 10.200.15.0/20
Private Subnet CIDR Range: 10.200.15.1/24

But on the Private Subnet CIDR Range above I get the following error:

Public and private subnet ranges must be valid and non-conflicting

Question: What I may be doing wrong, and how can I resolve the above error?

Remarks:

I have tried various variations of 10.200.15.1/24(e.g. 10.200.15.0/24, 10.200.15.255/24 etc.) but I keep getting the same error. I am sure there must be a correct Private Subnet CIDR Range that I am not using.
I noticed people have pointed out to some online tool such as the following, but I am not a networking expert, and I am not sure how exactly I can use these tools to get correct Private Subnet CIDR Range. CIRD Calculator, Subnet Calculator for IPV4, and IP Calculator.

UPDATE I'm following this tutorial from Azure team. When I tried the following settings, I get the error shown below:

Subnet range is not within the Virtual Network range

Anupam Chand · Accepted Answer · 2023-01-25T01:19:21.913

1

The CIDR tool I like to use is https://www.ipaddressguide.com/cidr.

Your public subnet 10.200.15.0/20 has a starting IP of 10.200.0.0 and ends with 10.200.15.255.

Your private subnet 10.200.15.1/24 is not even valid. You can check this SO answer as to why that is.

Change the private subnet to 10.200.14.0/24. Keep the public subnet as is. These are not overlapping and completely valid. 10.200.16.0/24 is outside the ip range of your vnet, so you can't use that.

edited Jan 25 '23 at 01:19

answered Jan 23 '23 at 07:15

Anupam Chand

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I tried your suggestion. Now I'm getting the error shown in **UPDATE** section that I just added to my post above. Any suggestions? – nam Jan 23 '23 at 15:55
This is because your address space ends wt 10.200.15.255. Change the private subnet to 10.200.14.0/24.Keep the public subnet as is – Anupam Chand Jan 24 '23 at 01:12
your suggestion in your comment works. You may want to edit your post accordingly - and I will mark that as an `answer` so other readers can benefit from it, as well. Thank you. – nam Jan 24 '23 at 15:24
Done the needful – Anupam Chand Jan 24 '23 at 16:33
I think you probably meant what you have in your comment: `Change the private subnet to 10.200.14.0/24. Keep the public subnet as is`. You may want to edit your post again. What you have in your comment worked for me. – nam Jan 24 '23 at 16:57
Done that now.. – Anupam Chand Jan 25 '23 at 01:19

score 0 · Answer 2 · answered Jan 23 '23 at 08:22

I tried to reproduce the same in my environment to create Azure Databricks Workspace with existing Vnet:

I have created Azure Databricks workspace with existing Virtual Network.

In your deployment you have mentioned public subnet CIDR range: 10.200.15.0/20 is in same Vnet Adress space range: 10.200.0.0/20, so there is a possibility of conflict the network.

To resolve the issue, create different subnet range for both Public and Private CIDR, while you are creating the Azure Databricks workspace.

I created a virtual network, like below.

Go to Azure Portal > Networking > Virtual Network.

enter image description here

Under IP address section, add the below IP configuration details.

enter image description here

Once Vnet deployment is complete, navigate to Virtual Network and select Address Space under settings option, add additional address space range, like below.

enter image description here