Last week VMware released update 4 of its ESX hypervisor. The upgrade includes several new or updated components that many users will want. But VMware has also removed some vital functionality that could leave users of its free ESXi hypervisor stranded.

For example, the PowerShell interface has been switched to what VMware calls “read only” mode.

PowerShell is a Microsoft technology that is gaining wide support from users and vendors as a way to script server management tasks that interact with applications from multiple vendors.

This new read-only mode allows PowerShell scripts to list the VMs running on a host but does not allow them to make changes, such as being able to start and stop VMs, or make snapshot backups of them. The full PowerShell interface is still available to people that have paid for licenses to use ESXi, but anyone that had been using PowerShell scripts with a free version could now find many of their scripts don’t work.

Likewise, VMware has tried to stop third party software from using many of its API calls. Some third party software vendors used these API calls to make products that worked with free versions of ESXi.

For example, Veeam Backup 3.0 is one of the few products that can make backups of VMs hosted by the free ESXi. However, Veeam Backup used VirtualCenter API calls. People that installed the latest free ESXi found their backup jobs failed on the new hypervisor. Of course, Veeam immediately updated its product so it worked properly despite the VMware change, but users need to patch their Veeam Backup software to make it work properly with Update 4.

The changes in free ESXi functionality seem to indicate that VMware wants independent software vendors to support only those users that have paid for licenses. But pulling the carpet out from under existing users is not likely to win their hearts and minds.

Even those that have yet to try it will also probably be asking themselves why on Earth they would invest time and other expensive resources hosting VMs on ESXi if they could not manage those VMs properly, for example, by being able to make backups.

Removing all this functionality from the free ESXi seems to be intended to encourage people to upgrade to a licensed version. It might push them towards a different free hypervisor instead.