Configuring VNET integration of Azure Redis and Web App

March 9, 2019Tech Notes 2 minsComments Off on Configuring VNET integration of Azure Redis and Web App

To configure Azure Redis with the VNET support, we can follow the steps described in this document. And to integrate Azure web app with a VNET, there is a detailed document for it as well. In this post, I listed some of the common issues that one might hit during the configuration.

  1. The VNET integration for Azure Redis requires an empty subnet for the VNET that is created with Resource Manager. This subnet needs to be created before you create Azure Redis. Otherwise, the configuration would fail.
  2. The subnet for Azure Redis can be protected with a network security group (NSG). Usually the default NSG rules are good enough for protecting the connections. If you need further hardening, you will have to create rules based on the ports list in the Azure Redis document.
  3. To troubleshoot the connection between Azure web app and Azure Redis, you can use the Kudu of web app. There are two tools built in with the web app for network troubleshooting:
    nameresolver.exe can be used to test the DNS functionalities, and
    tcpping.exe     can be used to test if the host and port can be pinged. But you cannot test the Redis function directly from the Kudu.
  4. Once the VNET integration is configured, the Redis console in Azure Portal will not work anymore. To test the Redis functions with tools such as redis-cli, you will have to build a VM in the VNET and connect to Azure Redis from it.
  5. If somehow your web app cannot access the Azure Redis, although the network configurations are correct, you can try to sync the network for App Service Plan. See this issue for details. Make sure you don’t hit any error when syncing the network.