According to the VMware vRealize Operations Reference Materials, Service Discovery is a feature that allows you to automatically discover and monitor the services running on your virtual machines. Service Discovery can use two methods: credential-based and credential-less. Credential-based Service Discovery requires you to provide guest credentials for each virtual machine, while credential-less Service Discovery uses VMware Tools to run scripts on the guest operating system without requiring credentials.
For Linux virtual machines, credential-less Service Discovery requires the installation of Telegraf agent, which is a data collection and reporting agent that communicates with VMware Tools. If the Telegraf agent is not installed on the Linux virtual machines, Service Discovery will fail to authenticate and collect data from them. Therefore, option A is correct.
Another requirement for Linux virtual machines is to enable the open-vm-tools-sdmg package, which is a service discovery management pack that allows VMware Tools to runscripts for Service Discovery. If the open-vm-tools-sdmg package is not enabled on the Linux virtual machines, Service Discovery will also fail to authenticate and collect data from them. Therefore, option D is correct.
The other options are not correct because they are not related to the authentication status of Service Discovery.
Option B is not correct because the required network ports are not specific to Linux virtual machines, and they are only needed for credential-based Service Discovery. Option C is not correct because the version of VMware Tools does not affect the authentication status of Service Discovery, as long as it supports the credential-less method. Option E is not correct because the Endpoint Operations agent is not required for Service Discovery, and it is used for a different purpose of collecting metrics and properties from the guest operating system and applications. References:
Service Discovery Overview
Credential-Less Service Discovery with vRealize Operations
Install Telegraf Agent on Linux Virtual Machines
[Enable open-vm-tools-sdmg Package on Linux Virtual Machines]