Using a Xen virtual appliance to manage your VMware servers

One of the great things about virtualization is the amount of money you can save companies, not just in hardware costs, but also the on going costs of keeping machines in a data centre and a rack, and feeding them with power and air conditioning.

Well, I built several ESXi servers for the current bank balance filling company, and they needed an easy and affordable way to manage them on the cheap. Now, I have always thought that VMware workstation is very affordable, so I built a Vmware virtual appliance to look after the servers with Vmware vSphere client. This however proved too expensive for them and they wanted something at zero cost to the company.

It is obvious that the management virtual appliance has to be on a different virtual infrastructure to that which it is supporting, so I built another virtual appliance , this time on our Xen server. As the virtual appliance has to be built with windows XP as it's base and then security hardened, the Xen server has to have the Intel processor enhancements turned on in the BIOS, otherwise it just won't fly.

The Xen server is based on RedHat Enterprise Linux 5.4, which comes with a lot of enhancements to the virtual machine management program - virt-manager, and it is very straight forward now to configure new virtual machines.

All I had to do to allow remote management of this appliance was to turn on the terminal services process within XP, and now people can use the "remote desktop connection" program to access this VM and control the ESXi servers using vSphere client.

Xen offers great performance, and this solution works really well, and didn't cost a penny.

If you want real virtual speed with your Jumpbox appliances use Xen not ESXi

As you will have seen on my blog recently we had a situation that meant I had to move one of our Jumpbox virtual appliances from a failed Xen server to a new ESXi server. Now these servers are exactly the same specification, HP DL380 G5 with 32GB RAM and 2 x Dual Core Intel Xeon CPU's , so not exactly supercomputers, but more than enougth to do what we want with them.

Well here is the thing, Jumpbox say that VMware are one of their main supported platforms and , Tier 1 partners I think they call it, and open source Xen is Tier 3. So how come then the virtual appliance runs significantly faster on Redhat Enterprise than it does on Vmware ESXi? When I say significantly, I'm not joking. The virtual appliance is the moinmoin wiki. On the ESXi platform trying to edit a post is painfully slow, 30 seconds to open the editor. On Xen it is 1-2 seconds at most, so I don't need a stop watch to see something is wrong.

I have gone through the settings for the Vmware server, something I don't have to do with Xen, and given it garanteed resources and CPU power, no difference. I could, if I fancied wasting a small part of my life, investigate the Advanced settings for the ESXi server, but again why would I when with Xen it just flys?

I don't know the answer thats for sure, and especially when you know that the Jumpbox appliance is running with the QEMU hardware emulator on Xen, as it's not para-virtualized! Emulators as I'm sure you know are not supposed to be that fast.

I think I'm going to chat to Jumpbox about this, as it really does seem odd. The only thing that may have affected the performacne is the fact that I had to migrate the appliance to ESX format from Server format, but surely once this process is completed the virtual image should be good to go.