The scenario describes a PostgreSQL HA deployment managed by NDB, where an NDB-managed VLAN (PGSQLVLAN40) restricts database communication to only within VLAN 40. This indicates a network isolation issue, likely due to VLAN segmentation or routing misconfiguration, preventing communication with external networks or other VLANs. Since NDB manages the VLAN and assigns it to the database VMs, the issue lies beyond NDB’s direct control and involves the underlying network infrastructure (e.g., switches, routers, or Prism Element network settings).
Here’s why the other options are insufficient:
A. Use VLAN 1: VLAN 1 is typically a default VLAN and not recommended for production use due to security and isolation concerns. Changing to VLAN 1 does not address the root cause and could introduce further issues.
B. Change the Default Gateway on the PostgreSQL servers and update NDB: While adjusting the default gateway might enable external communication, this is a workaround rather than a fix. NDB manages the network configuration, and manual changes could be overwritten or cause inconsistency. The root issue (VLAN routing) remains unaddressed.
D. Delete the database servers, VLAN name PGSQLVLAN40, and redeploy: This is overly disruptive and unnecessary, as recreating everything under a new VLAN name does not guarantee resolution unless the network configuration is corrected.
The best approach is to engage the networking team to investigate and resolve the issue, such as configuring inter-VLAN routing, updating firewall rules, or adjusting the default gateway at the network level. Going forward, the administrator should collaborate with the networking team during VLAN planning to ensure proper connectivity. Thus, the verified answer is C.
Official Nutanix Database Automation References
Nutanix Database Management & Automation (NDMA) course, Module 4: Troubleshooting NDB, Lesson 4.1: Identifying and Resolving Network Issues.
Nutanix Certified Professional - Database Automation (NCP-DB) v7.5Knowledge Objectives, Section 4: Troubleshoot NDB Solutions, Objective 4.2: Resolve Network-Related Issues (applicable to v7.5).
Nutanix NDB Administration Guide: "Networking Considerations for HA Deployments" section.
