Tech for the Enterprise

I have a vCenter server 4.0 and I went to upgrade one of my host machines. They were all running 3.5. The upgrade could not have been easier using the vCenter upgrade manager. Once the host rebooted it would not stay connected to the vCenter server. I could not figure it out the remaining 3.5 hosts stayed connected just fine.

Did some searching turned out I needed to add the IP address of the vCenter server into the Managed IP Address field under vCenter Server Settings.

See this article. http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1011647

Is it possible to “power off” a suspended VM Workstation? Yes. I had this problem when I tried to resume a suspended VM on Workstation 6.5 and it kept getting an error. I knew there was nothing going on when I suspended it so I decided to just power it down. Well, there is no option for that.

What you have to do is go into the folder that contains the VM and delete or as I did rename the .vmss files. If you rename them make sure the name change is in or after the extension. Example: myvmfile.vmss.old. This essentially pulls the plug on the power. You should be able to boot up your VM now.

If you have ever gotten this error it can cause a sinking feeling in your stomach. As good as virtual machines are and as much as I love them the one thing that can cause anxiety is if something should happens to the files that make up the virtual machine.

One Saturday morning I had to install updates on a critical mail server so like always I went to make a snapshot first. This way if something goes terribly wrong I just revert to the snapshot and I am back in business. So I right click on the virtual machine to take a snapshot. Instead of seeing in the task list the bivalent and always welcome “Completed” I saw “Detected an invalid snapshot configuration”. I thought oh no what has happened? I did some digging and someone recommended cloning the machine and that would take care of the issue. I thought that would be too easy but it worked perfectly.

How did I get into this predicament in the first place? This is a Windows 2003 Server and I needed to make some changes. I need to delete one hard drive and add another. The machine already had a snapshot on it before I made these changes. Thus the problem if you add and or delete drives while the machine has a snapshot the VM can get confused and thus you are stuck.

For me this worked. Hopefully it will help someone else.

Why would a company want to switch from physical servers to a virtual server? (Note: Some of the same reasons apply to desktop virtualization but most people run desktop virtualization for very different reasons.)

When you think of virtualization the first thing that comes to mind is you have to buy fewer machines thus you save money. In my opinion this is the least of all the benefits of going virtual. Even if the initial cost was the same to go virtual as physical there are several compelling reasons to go with virtualization.

I think the biggest reason to switch to a virtual environment is the ease of management. You have all your servers in one place and can add a hard drive, increase the memory and other modifications of a virtual machine remotely. If you pair visualization with something like HP’s iLO (Integrated Lights Out) you have a system that is hard to beat. The iLO lets you do 99% of everything you do with a server without being there (Dell has something similar but I feel HP makes the best servers in the world). Put both of these together and you can manage everything from your home office.

Next we have the ability to recover a machine in record time. With the proper backup method you can recover a machine in a matter of hours or even minutes depending on how big it is and the physical hardware you are using. The complexity of the software installed in the machine does not matter because you restore the whole machine in one shot.  What is more you do not have to have similar hardware. You can have a virtual machine on a Dell and restore it to an HP without any problem at all.

Then there is the ease of deployment of new virtual machines. You can use an ISO of the OS or have a Template of a standard machine and deploy it within minutes.

Lastly we have the consolidation story which is what normally attracts people’s attention to virtualization in the first place. This is where you can put several servers on one piece of hardware. Is there ever a time when you would not want to go virtual? Yes. There are some applications that take so much CPU or IO resources so it would not be good to put them on a virtual machine. For example Exchange Server that houses many mail boxes would not be a good candidate for virtualization.

Virtualization can fit even a small installation because it has so many benefits.

Virtualization saves money at every turn and can save your whole company if disaster strikes.