Windows Azure Virtualization. Major Limitations Compared to OpenStack, KVM.

I plays with Windows Azure, VNets and Virtual Machines quite often. On a day to day basis, I do also works with KVM and Virtualbox for home use.

Based on my experience, Below are the two major limitations, I face with Windows Azure.

1. No Nested Virtualization support

2. No Custom DHCP Server

For instance, KVM supports nested virtualization. That means you can access Hardware Virtualization Extensions (AMD-V, Intel-VT) inside a KVM Guest. So you can install KVM inside another KVM guest and pass the hardware assisted virtualization support to the nested VM’s (Virtual Machines). So the nested guests can have performance improvements.  This nesting of virtualization can go to any level, at least theoretically. This feature can come in handy, if you need to experiment with virtualization, in an already virtualized environment.

To check this nested virtualization support in Windows Azure, I’ve tried to install Hyper-V inside another Windows Azure Virtual Machine. But it failed and reported that nested virtualization is not supported.

Also you cannot install and run your own DHCP server instances in Azure. Azure VM’s rely on the built in Azure DHCP servers, to lease IPs. But you can run your own DNS servers (Like a Windows Server 2012 instance with DNS role installed)

When it comes to KVM, you’ve the flexibility of having your own custom DHCP server, and can configure different IP ranges as you need.

Whether these features ever get into Azure? Someone can give a glimpse on that in the comment section.