OK. Once you have a good working base VM system, it is quite easy to implement new VMs for different tasks.
The first step is to create your base Linux/CentOS system or Windows system that will be used for future VMs. This system will essentially be a fresh install with all the service packs and updates applied to it. When necessary you will run it and apply new updates.
Now comes the duplicating task. That is, creating a new VM from this base system so you can experiment or create a new server. Here are the steps.
1) Create a new Virtual Machine from the VM Server access panel
2) Choose the appropriate operating system when asked. For CentOS 5.2 use Linux Redhat 5.x.
3) When asked for what hard drive to install choose none. You will later attach a copy of the base systems disk to this new VM system.
4) Choose the other setting as normal and appropriate for your situation. Remember, you are essentially creating a virtual computer without a harddrive. In my case, I needed to select a my “BridgeCard” network card for the networking setting instead of the default NAT.
5) Once created, you can now go to the summary page of the VM to add the new copied harddisk.
6) First,copy and paste the vdmk file for the base system to the new VM folder. Then rename the vmdk file to the name of that makes more sense for the VM that you just created. Usually the same name as the VM machine.
7) Now, you add the copied harddisk to the VM machine by choosing the Add New Hardware on the left hand side of the VM summary page. When adding the hardisk, choose the “Use existing Harddisk” option and select the copied and renamed vmdk file from the datastore.
That’s it. You now have a new working copy of the base VM. Your next steps would be to start configuring it to your liking such as adding the desired programs and services for it desired task, changing its IP, internal computer name, and MAC Address (if needed, for servers etc.), setting firewall setting to allow traffic to it and setting up connections to it such as external database servers.
Enjoy. The fun has just begun.