General availability: Azure Data Explorer and subnet delegation
Published date: 17 June, 2021
Azure Data Explorer (ADX) supports virtual network injection. In the past customers had challenges with the manual way of configuring the Network Security Group (NSG) rules needed to succesfully deploy the service to a virtual network. Designating the subnet to "Microsoft.Kusto/clusters" automatically applies the required NSG rules.
Subnet delegation enables you to designate a specific subnet for an Azure PaaS service of your choice that needs to be injected into your virtual network. When you delegate a subnet to Azure Data Explorer, you allow the service to establish some basic network configuration rules for that subnet, which helps ADX operate in a stable manner.
Since the beginning of June 2021, deploying an Azure Data Explorer into a virtual network enforces subnet delegation for "Microsoft.Kusto/clusters" to be configured. Opting out of this requirement is possible using the Preview features blade.