virtual machine and cloud computing
hi everybody I'm very new to IT field can anybody explain me relation between virtual machine and cloud computing . In my firm they using a private cloud using ubuntu eucalyptus tool . They uses KVM. when ever i demand the resource they says we will give u the virtual machine is cloud computing means providing virtual machine as i study cloud computing over the net it sound like a different technology . More important i want to know does the specification(characteristic ) of virtual machine depend on the physical machine ? which they are imitating or we can provide our specification such as making a virtual machine of 100 GB storage while the physical machine has only 20 GB hard disk?or is it possible to make a virtual machine a virtual machine 0f 4 gb RAM while physical machine is having ram of 128 mb please explain me this concept I'll be thankful to all of you forever
Answer
Here it is in a nutshell:
A cloud is built up of numerous physical machines (the hardware). Each of these machines then run multiple virtual machines, which is what are presented to the end-users.
Virtual machines are only limited in the way that their specifications cannot exceed that of their host (the underlying physical machine).
So no, if the physical machine on which your virtual machine runs only has 20GB of harddrive space, you cannot ask them to create a VM with 100GB of disk space. (The same applies to RAM).
That being said, the way storage works on the EC2 (Amazon Compute Cloud) is a bit different. The storage is done offline, so in that case it would be possible to request drive space that exceeds the host, but again not exceeding the physical size of the actual place where the storage is done.
Furthermore, the restriction placed that Vitrual Machines cannot exceed the host capabilities also applies if you have multiple VMs running on the same host. In that case, the shared capabilities of the VMs cannot exceed that of the host. For example, if you have 4GB of RAM on the physical machine, then you can have 2 VMs each with 2GB of RAM.