When using the "Patch OS now" feature in NDB to apply updates to a Red Hat-based operating system, the administrator can limit updates to security patches only by leveraging the Advanced Options. Under the "Custom commands" section of the operating system patching command window, entering yum update --security instructs the package manager to install only security-related updates. This ensures the system remains secure without applying all available updates, which could introduce instability.

Other options are incorrect or incomplete:

A. Point the database VM to a custom patch repository and enter yum update --security command: This requires manual intervention outside NDB’s patching framework.

B. Check Advanced Options and under Pre-post commands, enter yum update security in the pre-operating system patching command window: Pre-post commands are for pre/post actions, not the main patching process, and the syntax lacks the --security flag.

C. Point the database VM to a custom patch repository before using the Patch OS now feature: This sets up a repository but doesn’t specify security-only updates within NDB’s interface.

Thus, the verified answer is D, aligning with NDB’s patching customization.

Official Nutanix Database Automation References

Nutanix Database Management & Automation (NDMA) course, Module 6: Maintenance and Patching, Lesson 6.3: Creating Maintenance Plans.

Nutanix Certified Professional - Database Automation (NCP-DB) v7.5Knowledge Objectives, Section 6: Optimize NDB Solutions, Objective 6.3: Manage Maintenance Plans (applicable to v7.5).

Nutanix NDB Administration Guide: "Patch OS Now with Custom Commands" section.