Problem
When using Azure private endpoints for services that interact with Terraform runs or are used as external components in Terraform Enterprise, you may encounter inconsistent communication errors.
Cause
These errors typically stem from misconfigurations in networking, DNS, or routing. The following solutions provide checklists to validate the configuration in each of these areas.
Solutions
Solution 1: Verify Network Configuration
Review your network configuration to ensure traffic can flow correctly.
- Verify IP Address Assignments: Confirm that the private endpoint has the correct IP address assigned and that there are no conflicts with other resources.
- Check Network Security Groups (NSGs): Review the NSG rules for the private endpoint's subnet to ensure the necessary traffic is allowed and there are no conflicting rules. For more details, refer to the Azure Network Security Groups Overview.
- Validate Route Table Configuration: Ensure the route tables associated with the private endpoint's subnet and the connected resources are correctly configured with the appropriate routes.
- Examine Network Virtual Appliances (NVAs): If you have Network Virtual Appliances deployed, verify their configurations to ensure they allow the necessary traffic flow.
- Use Network Monitoring and Diagnostics: Use Azure Network Watcher to monitor and diagnose network traffic with tools like Connection Monitor or Packet Capture. For more details, refer to the Azure Network Watcher Monitoring Overview.
Solution 2: Validate DNS Configuration
Incorrect DNS resolution is a common cause of connectivity issues.
- Validate DNS Resolution: Check if the DNS server or service used by the private endpoint and the connected resources is functioning correctly. Ensure the private endpoint's DNS settings are accurate.
- Review DNS Settings: Verify the DNS configurations for the private endpoint and the connected resources, including the virtual network's DNS settings and the accessibility of the DNS server's IP address.
- Consider DNS Forwarding: If your DNS server does not directly resolve the resource's hostname, configure it to forward DNS requests to the appropriate server.
- Check DNS Caching: Clear the DNS cache on the private endpoint or client machine to ensure the latest DNS information is retrieved.
- Examine DNS Timeouts: Monitor the private endpoint's DNS queries for delays or timeouts, which could indicate DNS server performance or network connectivity issues.
- Analyze DNS Logs: Review DNS logs for error messages or unusual patterns, such as DNS query failures, server errors, or timeouts. For more details, refer to the Azure DNS Overview.
Solution 3: Inspect Route Table Configuration
Ensure that network traffic is being routed correctly to and from the private endpoint.
- Verify Associated Subnets: Check that the private endpoint and the connected resources are associated with the correct subnets and that the subnets have the correct IP address ranges assigned.
- Confirm Default Routes: Review the default route settings in the route table for the private endpoint's subnet, ensuring they correctly direct traffic to the appropriate next hop.
- Check Specific Routes: Inspect the route table entries for specific routes and verify that they accurately point to the correct next-hop addresses or virtual appliances.
- Evaluate Next Hop Settings: Ensure the next hop settings specified in the route table are correct and reachable.
- Diagnose Route Propagation: If you use Virtual Network Gateways or Azure Firewall, verify that route propagation is enabled and that the necessary routes are propagated correctly.
- Check for Route Table Conflicts: Ensure there are no conflicting route table entries that might cause incorrect routing decisions or block traffic.
- Monitor Network Traffic: Capture and analyze network traffic flows using tools like Azure Network Watcher to monitor traffic from the private endpoint's subnet to the connected resources. For more details, refer to Azure User-defined routes overview.