A well-designed reference host connects to all services such as syslog, NTP, and so on. The reference host setup might also include security, storage, networking, and ESXi Dump Collector. You can apply such a host's setup to other hosts by using host profiles.

The exact setup of your reference host depends on your environment, but you might consider the following customization.

NTP Server Setup
When you collect logging information in large environments, you must make sure that log times are coordinated. Set up the reference host to use the NTP server in your environment that all hosts can share. You can specify an NTP server by running the esxcli system ntp set command. You can start and stop the NTP service for a host with the esxcli system ntp set command, or the vSphere Client.
Syslog Server Setup
All ESXi hosts run a syslog service ( vmsyslogd), which logs messages from the VMkernel and other system components to a file. You can specify the log host and manage the log location, rotation, size, and other attributes by running the esxcli system syslog command or by using the vSphere Client. Setting up logging on a remote host is especially important for hosts provisioned with vSphere Auto Deploy that have no local storage. You can optionally install the vSphere Syslog Collector to collect logs from all hosts.
Core Dump Setup
You can set up your reference host to send core dumps to a shared SAN LUN, or you can install ESXi Dump Collector in your environment and configure the reference host to use ESXi Dump Collector. See Configure ESXi Dump Collector with ESXCLI. You can either install ESXi Dump Collector by using the vCenter Server installation media or use the ESXi Dump Collector that is included in vCenter Server. After setup is complete, VMkernel memory is sent to the specified network server when the system encounters a critical failure.
Security Setup
In most deployments, all hosts that you provision with vSphere Auto Deploy must have the same security settings. You can, for example, set up the firewall to allow certain services to access the ESXi system, set up the security configuration, user configuration, and user group configuration for the reference host with the vSphere Client or with ESXCLI commands. Security setup includes shared user access settings for all hosts. You can achieve unified user access by setting up your reference host to use Active Directory. See the vSphere Security documentation.
Note: If you set up Active Directory by using host profiles, the passwords are not protected. Use the vSphere Authentication Service to set up Active Directory to avoid exposing the Active Directory password.
Networking and Storage Setup
If you reserve a set of networking and storage resources for use by hosts provisioned with vSphere Auto Deploy, you can set up your reference host to use those resources.

In large deployments, the reference host setup supports an Enterprise Network Manager, which collects all information coming from the different monitoring services that are running in the environment.

Figure 1. vSphere Auto Deploy Reference Host Setup

The reference host setup might include setup for DNS, NTP, syslog, security, networking I/O filters, DHCP or static IP, and monitoring.

Options for Configuration of a vSphere Auto Deploy Reference Host explains how to perform this setup.

Watch the video "Auto Deploy Reference Hosts" for information about the reference host setup: