Sunday, July 6, 2014

The state of Hypervisor Virtualisation 2014

I wish someone would just make the perfect hypervisor.

Basically I guess what I'm asking for is ESX and VCenter to be released as Open Source products and the file system changed to EXT4.

I guess I need to provide some background to that statement...

I recently had a disk drop out of my home ESXi server with nothing particularly important on it but just for curiosities sake I thought I'd see what's involved in restoring a VMFS partition (more specifically, a VMFS5 partition).

Let me sum this up for you: good f#$%ing luck.

While NTFS and EXT3 have many good recovery tools available, there are basically two for VMFS:

PartedUtil and vmfs-tools for Linux.

PartedUtil sucks. Sorry, there's just nothing else to say about that application.

vmfs-tools (a VMFS5 enhanced version of the Google open source VMFS3 driver) is somewhat better but is still a very basic tool for something that a Windows or Linux application would barely break a sweat to achieve the same thing.

I started talking about VMFS with some of the more knowledgeable server engineers I work with who advised that "now that I mention it" they seemed to also think that disks may very well die faster in VMWare environments.

Obviously in an enterprise environment you will be running your disks in enterprise grade SANs so in the event of a disk failure it's a simple swap out / swap in and add to the array but it did seem very odd that disks failed faster when acting as targets for a VMWare environment.

Conspiracies aside, I've developed gripes relating to the changes that occur between different versions of ESX.

Finally, license costs.
Oh the license costs.

In a world where Xen, Hyper-V and KVM are taking off, VMWare licensing costs should only be going in one direction.

So, as I need to be across all things hypervisor in my job, I thought I'd run up Xen (and in time KVM) to see what it's like at this point in time (as I remember about two years ago Xen was incapable of CPU resource reservation).

In recent times, Citrix has relinquished Xen to being an Open Source product once again (which means it has now gone full circle) 

There are two options for running a Xen hypervisor at this point in time.

The first is to used the last cut as released by Citrix which is at least stable with a good interface.

The second is to install XenServer on top of a Linux distro of your choice.

This is quite a new option and not one that I have time to play with right now.

On a sidenote, Amazon Web Services apparently run their own custom cut XenServer environment.

I don't know if that's a good or a bad thing.

Anyway, I fired up the latest Citrix rolled up version of Xen (6.2) and not much has changed.

It still can't do CPU resource reservation (high medium low is not reservation) and the drivers for DVD / BD drive emulation still don't work properly for Windows guests.

These are the exact same problems I had two years ago. Fail.

Oh - and the recently released CentOS 7 doesn't boot after install.

There are two potential issues I see with Xen.

First: How much has Citrix mucked with Xen and are these changes actually for the good of the product?

Second: Now that it has been re-released into the Open Source domain, the dev community has to scramble to work with an inherited codebase.

The code might not actually be what devs want to work with (as in they might disagree with the way some elements of the app are built) and given that the code is so established, that could be a problem. 

This might result in a slowed development cycle and lack of community support.

So, back to ESXi for me for the time being.

Hopefully KVM has more to offer...

No comments:

Post a Comment