In the scenario presented, the NC2 cluster was initially deployed with two Flow Gateways (FGW1 and FGW2) in HA. After adding four bare-metal nodes and additional workloads, two more Flow Gateways (FGW3 and FGW4) were added to handle the increased bandwidth for north/south traffic. Given the configuration, the existing workloads can utilize all available Flow Gateways (FGW1, FGW2, FGW3, and FGW4) for No-NAT (routed) traffic paths. This setup allows for Equal Cost Multipath (ECMP) routing, distributing traffic load across all Flow Gateways.
References
* Nutanix Flow Networking

* Outbound Rule Necessity: For successful cluster deployment, certain outbound connections must be allowed to ensure proper download and configuration of resources.
* Critical Destination: "Https://downloads.cloud.nutanix.com/*" is a critical endpoint from which the Nutanix software and updates are downloaded during the cluster deployment process.
* Functionality: Ensuring an outbound rule for this destination allows the deployment to fetch necessary files and updates, enabling smooth cluster setup and operation.
* Other Destinations:
* Https://portal.nutanix.com/: Used for accessing the Nutanix portal, not directly related to deployment downloads.
* Https://support.nutanix.com/: Used for support-related tasks, not for deployment-specific downloads.
* https://nutanix.dev/: Related to development and API documentation, not necessary for initial deployment.
* Conclusion: Outbound connectivity to "Https://downloads.cloud.nutanix.com/*" is essential for downloading deployment resources.
References:
* Nutanix NC2 on Azure Network Configuration Guide
* Azure Network Security Documentation

* my.nutanix.com Portal:This portal provides access to various Nutanix services and features, including the NC2 deployment interface.
* NC2 Tile:The NC2 tile within the portal is specifically designed for deploying and managing Nutanix Cloud Clusters. It provides the necessary tools and settings to initiate and configure NC2 clusters on Azure or other cloud environments.
References:
* Nutanix NC2 Deployment Guide
* my.nutanix.com Portal Documentation

* Network Configuration: Using a specific IP range for a VNet can cause conflicts if that range is reserved or already in use by the cluster's internal operations.
* Internal Usage: In NC2, certain IP ranges are reserved for internal cluster functions and should not be used for VNets to avoid IP conflicts and connectivity issues.
* Impact: If the 10.100.0.0/16 range is reserved for internal usage, using it for a VNet would lead to IP conflicts, causing network connectivity issues.
* Verification: It's important to verify the reserved IP ranges in the NC2 documentation before assigning them to VNets.
* Conclusion: The connectivity issues are likely due to using the 10.100.0.0/16 range, which is reserved for internal cluster usage.
References:
* Nutanix Networking Guidelines
* Azure Virtual Network Documentation

* Outbound Communication Whitelisting:For NC2 Azure API calls and telemetry data to function correctly, certain outbound communications must be allowed. If these communications are not whitelisted, API calls can fail, and telemetry or health data might not be reported correctly.
* First Check:Given the symptoms (failing API calls and missing telemetry), the first step should be to ensure that all necessary outbound communications are correctly whitelisted. This includes ensuring that endpoints and services required for NC2 operation are accessible.
References:
* Nutanix NC2 Networking Requirements
* Azure Networking and Security Configuration Guide