Few different new vSphere features have been exhaustively discussed since it was launched back in May’09. I have seen a number of discussions and papers about Fault Tolerance, Storage Thin Provisioning and vDistributed Switches however not much has been said about Host Profiles.

Host Profiles greatly simplify host configuration management in scale-out deployments through user-defined configuration policies. You can use profile policies to eliminate per-host manual host configuration and efficiently maintain configuration consistency and correctness across the entire datacenter(*).

A Host Profile policies can capture the blueprint of a known, validated "golden" configuration and use this to configure networking, storage settings, security settings, and so on for multiple hosts. Host profile policies also monitor compliance to standard host configuration settings across the datacenter.

Using Host Profiles

Profile configurations can be managed via GUI (viClient), vSphere APIs or PowerCLI. Some software and hardware vendors already started to integrate their products with Host Profiles to enhance functionalities such as periodic scans to uncover inconsistencies and provide reporting for Change Management (ITIL) compliance.

Some material have already been published so I won’t recreate. I’m listing some good links and references.

VMware vSphere 4 - Host Profiles Feature from Xtravirt (Paul Davey)

Host Profiles Official VMware Demo

vSphere Host Profiles by Jason Nash (video)

Managing host profiles with vSpherePowerCLI! by Yavor Boychev (video)

Backup/Restore a Host Profile by Graig from the Malaysian VMware Community

Licensing

To be able to use Host Profiles your vSphere environment must be licensed with Enterprise Plus package that also allows you to use vNetwork Distributed Switch, and Third Party Multipathing. It is clear to me based on this post from Eric Siebert  that Host Profiles is not one of the hottest features on VMware’s plate however administrators are considering upgrading their licenses to Enterprise Plus.  I believe Host Profiles will be soon on the hots  when all the hype about other features is over.

This post from Maish Saidel-Keesing explains licensing and pricing in detail.

Limitations

()*Host Profiles will not work work properly in a cluster containing ESX and ESXi hosts due to core differences, such as Service Console and Port Networks. The recommendation is that you create different clusters for each type of hosts and maintain a separate host profiles. This drawback by itself could represent a big challenge in Host Profiles adoption however VMware has already stated that only ESXi will be supported and gain new features in the future.

Other limitations:

• Only a single profile can be applied per cluster

• Logging on the host

is to the file “pyVmomiserver.log”

• Host must be in maintenance mode before a profile can be applied.

Things not covered by Host Profiles are:

• Licensing

• vDS policy configuration (you can do non-policy vDS)

• iSCSI

• Multipathing

Some information provided by Forbes Guthrie post.

My Personal Experience using Host Profiles

(Could Host Profiles be more intelligent?) I came across an interesting situation that I rather prefer to think it is a bug to be fixed than a natural behavior. In my production environment I created a Host Profile based on a ESX host (A) and the only difference to ESX host (B) was the NIC Teaming order.

When I applied the profile onto ESX host (B) vCenter informed that the only vSwitch and all port groups in use would be deleted and recreated, including the Service Console and vKernel.

I initially thought it is not possible so I manually changed the NIC Teaming order on ESX host (B) and when I requested to Check Compliance on host ESX (B) it was compliant.

In Summary a simple NIC teaming order change will cause Host Profiles to delete ESX vSwitch and all port groups efore creating it again with the correct configuration.

Few other administrators have been trough the same issue and the simply additional NIC to a vswitch would result in deleting vswitch in recreating vswitch0. However this ends with a communication error between vCenter and the ESX host because the management network is not available anymore (due to deleting vswitch0).

Final Considerations

I have found in many circumstances that use of Host Profiles will co-exist with unattended installations (scripted) helping administrators to achieve consistency over and further than datacenter

boundaries with minimal effort.

Not really related to Host Profiles but would be nice to see vApps understanding host configuration and deciding if that specific configuration or Host Profile applied to the host is adequate for grouped VMs to run.

Host Profiles is a powerful tool to maintain consistency amongst a large number of ESX hosts and will certainly benefit organizations who can afford the salty price of the Enterprise Plus package.

Other useful resources

Meet the Engineer Series: VMware Host Profiles

Have Fun and Break a Leg

http://virtualcloud.wordpress.com/

Andre Leibovici