[libvirt] VMware ESX: Allow ethernet address type 'vpx'

[Itamar Heim]

> From: Matthias Bolte [mailto:matthias.bolte at googlemail.com]
...
> 
> The ESX driver parses the VMX file of a virtual machine to gather the
> information needed for the dump XML function. The VMX entry
> ethernet0.addressType maybe set to vpx if the generated MAC address
> was generated by a vCenter and not by the ESX host itself. No direct
> interaction between the ESX driver and a vCenter happens in this case.
> 
> But there is direct interaction between the ESX driver and a vCenter
> if you order the ESX driver to migrate a virtual machine from ESX host
> A to ESX host B.
> 
> An ESX host itself is not capable of initiating a migration to another
> ESX host. Both hosts must be attached to the same vCenter and the
> vCenter initiates and controls the migration. So the ESX driver needs
> to know the vCenter for a ESX host in order to do a migration.
> Therefore the ESX driver URI format contains an vcenter query
> parameter.
> 
> More detailed documentation in HTML form will be added soon.
> 
> Matthias

[IH] thanks for the elaboration. So the driver can talk to both an ESX
server directly, or to vCenter. vCenter is used only for specific
operations (like live migrations), and you opted to connect directly to
ESX (rather than use vCenter API to start a VM as well) for the rest to
allow using in a vCenter-free environment as well?
Are there any other considerations to using ESX directly, or prefer to use
vCenter (say, if you ask vCenter to start the VM, you could benefit from
its load balancing capabilities, etc.).
Btw, does asking ESX to start a VM from shared storage checks for locks,
and prevents running same VM on two ESX in parallel, or must vCenter be
used for "cluster-aware" use cases?

Thanks,
   Itamar