Azure Redis Private Link Disconnection Issue Analysis

Hi Avinash,

Greetings!

We apologize for the inconvenience caused.

We would like to inform you that, this issue occurs when Azure Private Endpoints and Private DNS Zones are misconfigured or not fully isolated, even though the services involved are independent.

Here are the potential causes and Insights.

• Shared Private DNS Zone: Since Azure Redis restricts one Private DNS Zone per VNET, the deletion of the zwayam-cluster3 instance might have inadvertently affected the DNS records. When a Private Link is deleted, the associated DNS records in the Private DNS Zone might also be removed or altered, potentially impacting other instances using the same zone. Please refer to this link for more information. https://learn.microsoft.com/en-us/azure/private-link/private-endpoint-dns
• DNS Propagation Delay: Changes in DNS records can sometimes take a while to propagate. If the DNS record for zwayam-cluster3-central-india was temporarily unresolved due to the deletion of zwayam-cluster3, this could explain the disconnection until the new Private Link was established.
• Network Interface and IP Address Conflicts: Although each Private Link has an independent IP, the deletion of one Private Link might have caused a temporary conflict or reconfiguration in the network interface settings within the VNET. This could lead to connectivity issues for other instances until the network stabilizes.
• Private Endpoint Configuration: Ensure that the private endpoint configuration for zwayam-cluster3-central-india was not inadvertently altered during the deletion process. Sometimes, changes in one resource can cascade to others if they share underlying infrastructure.

We would recommend you to follow the below mentioned points to prevent this in the future.

1. Review DNS Zone Configuration: Check the Private DNS Zone settings to ensure that the DNS records for zwayam-cluster3-central-india are correctly configured and not impacted by the deletion of the other instance. https://learn.microsoft.com/en-us/azure/azure-cache-for-redis/cache-troubleshoot-connectivity
2. Monitor Network Logs: Analyze the network logs and metrics around the time of the incident to identify any anomalies or conflicts that might have occurred. https://learn.microsoft.com/en-us/azure/azure-cache-for-redis/cache-private-link
3. Isolate Critical Resources: Consider isolating critical resources in separate VNETs or DNS zones where possible to minimize the impact of changes to one resource on others.https://techcommunity.microsoft.com/blog/azurepaasblog/troubleshooting-azure-redis-connectivity-issues/1450361

I hope this information helps. Please do let us know if you have any further queries.

Hi @Avinash,

We haven’t heard from you on the last response and wanted to follow up to check if your issue has been resolved.

If you have found a solution, we would appreciate it if you could share it with the community, as it may be helpful to others. Otherwise, please provide more details, and we will do our best to assist you further.

Hello @Vijayalaxmi Kattimani. Thanks for your valuable information we are checking on this options please allow us some time we are working on it and will keep you posted.