VMware host profiles can simplify the process of deploying new hosts and can help prevent human error. Even so, you have to be cautious when working with host profiles.
VMware host profiles are easy to use -- maybe a little too easy. For example, if you want to set up a cluster, you can deploy a single host, generate a host profile from that host and then use it to effortlessly configure the remaining hosts in the cluster.
Due to this simplicity, it can be tempting to rush the process. This can lead to errors if you deploy a collection of hosts and only later discover that the host profile carried over an error. As such, it's best to bring the first host online and make sure its configuration is correct before you create a VMware host profile.
Despite the simplicity of VMware host profiles, it's best practice to avoid experimentation during production. Host profiles might not always work in exactly the way you'd expect. If you have never worked with host profiles before, try creating and using host profiles in a few nested ESXi hosts before moving on to a production environment.
Name VMware host profiles to alleviate confusion
VMware requires you to assign a name to the host profile you're creating. For example, if you create the host profile from the command line, the command contains a Name parameter that you can use to specify the profile's name.
The commands used to create a VMware host profile might look something like this:
$VMwareHost = Get-VMHost <name of the reference host>
New-VMHostProfile -ReferenceHost $VMwareHost -Name <the name that you want to assign to the profile>
When you specify a VMware host profile name, you can be as descriptive as you want to be. Rather than using a name like MyHostProfile, choose a name that conveys when and why you created the profile, such as ESXi67-Production-Cluster-September-2018.
Suppose you created a VMware host profile and used it to deploy a number of new hosts. Although the deployment and configuration of the hosts is complete, the host profile may still be useful because it contains a record of how the hosts are supposed to be configured. VMware even enables you to use your host profile to perform a compliance check. You can compare a host's configuration against the configuration outlined in the host profile to ensure no one has changed the settings.
The use of descriptive names is important here, as well, because the profile name can help you figure out which profile you should be using when performing compliance checks.
Another VMware host profile mistake is forgetting that every ESXi host is unique. There are likely certain configuration elements, such as IP addresses, that are unique to every host. You have to account for specific host settings when creating a profile.
The vSphere Web Client contains an option to edit a host profile. By doing so, you can make it so that an administrator has to supply certain settings at the time the profile is applied rather than the settings being automatically assigned as part of the profile. The exact steps for doing so vary depending on which profile settings you're modifying, but there will usually be a user-specified choice for options that need to be host-unique.
You can avoid most of the common VMware host profile issues by taking the time to experiment with host profiles in a lab environment. Once you get a feel for how host profiles work, you will be well equipped to use them in production.