Virtualisation, a pretty revolutionary technology. Not exactly new, been out for a few years at least.
What exactly does it do? It creates a virtual copy of your physical server (aka an entire computer stored as a file), which is really very, very mindblowing. It strikes me this way, because of the multiple benefits involved.
For example, in provisioning.
- The normal way: Need a server? You buy the hardware, spend hours installing the OS, then the packages required before it’s “ready” for configuration.
- The virtualisation way: Buy a server of sufficient computing power and memory the first time round.
Set the virtual machine up, which installs far more rapidly than a traditional setup to begin with, saving you time on installation. I’m not kidding on this because it took me like fifteen minutes to complete a clean Fedora install – this would have been unthinkable in the old days.
In addition, there’s no need to buy a separate set of hardware the second time round – all you do is to allocate resources to the new virtual machine, and it will behave exactly like a separate server. Amazing stuff.
- Driver issues: The virtual hardware drivers make it a lot easier, and these days OSes ship with the correct drivers so problems have been minimal – no problems seen so far, though I’m sure exceptions exist.
You can see that time is saved on OS installation, as well as hardware procurement. Less obvious is the fact that hardware and space is consolidated, which saves you space, power and hardware costs.
The best bit, is that the processing power and memory will be maximised in a virtualised environment. This is in contrast to the traditional 1:1 hardware to server model, where the CPU and memory is rarely if ever used to capacity. With efficiency in utilisation comes savings, because you can theoretically have a server with 16GB of RAM, and allocate it to various virtual machines that consume more than 16GB of RAM. The difference maker comes in sharing and prioritisation, something virtualisation technologies do pretty well these days.
And did you notice the best bit about the server being a file? You can create a snapshot or back it up somewhere else, and “restore” it to working order at short notice, should you have rolled a bad update or configured something incorrectly – very critical in a live environment.
Virtualisation makes things easier on test boxes as well – imagine being able to run multiple environments on your computer to thrash a product out on different platforms, right on your computer! And if it stuffs up, all you would have lost is the test VM, nothing serious.
Let’s talk about virtualisation benefits (specifically about VMware); stuff like being able to move virtual machines from one physical host to another without downtime, or to restart a virtual machine in another host if the original one went down. Things like these improve the efficiency of disaster recovery (DR) tremendously without the server administrator needing to rush down in the middle of the night – great stuff.
I’ll stop here before I start sounding like an overenthusiastic sales brochure, but since being exposed to virtualisation and having been through a course on it, I have gained a much deeper appreciation for the technology. Just amazing how impactful virtualisation has been to server management.