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What you should know about host profiles in VMware

Use VMware Host Profiles to keep configuration consistent between hosts and clusters across your vSphere, and avoid common errors and mistakes to maintain stability.

VMware Host Profiles is a vCenter Server tool that helps design and deploy ESXi hosts. It works by encapsulating a reference host configuration and converting it into a template on which you can configure other hosts or clusters. It ensures host conformity across an entire vSphere environment.

You can use host profiles to manage host configuration images without individual host-by-host interventions and to automatically apply host configurations across an environment. You can also automate compliance checks and host builds, and apply networking, storage and other settings across your environment.

VSphere cluster consistency

Consistency in vSphere clusters mitigates several risks inherent to a virtualized environment, and proper design is crucial to ensuring consistency. VMs in a vSphere design should be able to run on any physical host and also move freely between hosts.

You can use VMware High Availability (HA) and Distributed Resource Scheduler (DRS) to balance resources across hosts, which helps maintain consistency. HA can protect against server failure, and the consequent loss of all hosts on that server, and DRS minimizes the chances of overloading specific hosts.

However, the Host Profiles tool can also help maintain consistency. You can use it to define a desired host state for a cluster and automate the process of ensuring each host matches that configuration. It can also audit for consistent configuration and force errant hosts to return to a consistent configuration.

Host profiles in VMware and consistent configuration

With host profiles you can ensure consistent configuration for security, networking and storage across your VMware environment. This ensures all hosts behave in the same way, improving an environment's stability. If a host fails, Host Profiles enables you to remove the failed host and easily replace it with a preconfigured host identical to others in your environment.

Host profiles in VMware are typically easy to use. However, this simplicity can make it tempting to rush through the host profile process and lead to errors.

To use this feature, start by extracting your reference host's configuration into a new host profile. To do this, right-click the reference host and select Host Profiles > Extract Host Profile from the drop-down menu. You can then manage it and tweak your configuration in the Policies and Profiles section of your vSphere web client.

You can also easily manage host profiles through PowerCLI. Use PowerCLI cmdlets -- short scripts -- to create new host profiles, attach hosts and clusters to a host profile, or test for host profile compliance.

Avoid host profile errors

Host profiles in VMware are typically easy to use. However, this simplicity can make it tempting to rush through the host profile process and lead to errors.

A few best practices can help avoid problems with your host profiles. Always start by bringing your first host online and checking its configuration before creating a host profile. Avoid experimenting with your host profiles in your production environment; save that for your testing environment.

Also ensure you properly name each of your host profiles. The more descriptive those names are, the easier it is to perform tasks such as compliance checks and setting configuration elements.

Use Host Profiles to alter configurations in VMware

It's possible to use the Host Profiles tool to modify many host configurations in VMware. For example, you can change a forgotten root password for any host connected to vCenter.

To do this, navigate to Host Profiles in your Active Directory. Select Extract Host Profile and choose the appropriate ESXi host, then enter a name for your new host profile. Next, return to the Host Profiles page and select your new profile. Click Edit Host Profile. You should see pages that include Advanced Configuration Settings and General System Settings, both of which you can use to change configurations in your host profile.

When you are finished with configuration, click Finish. Then apply this host profile to a host or cluster by navigating to Attach/Detach Hosts and Clusters, selecting the appropriate ESXi host, and clicking Finish again. Navigate to the Hosts & VMs page and select Remediate for the altered host to remediate the host and ensure your changes stick.

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