A virtual server, a virtual machine (VM), and an instance are different names for a collection of virtual computing and disk resources, a guest operating system, and its applications.
- Fewer physical servers are needed to run the applications you need because you can host multiple isolated virtual machines on a single server. Thanks to virtualization, we are moving away from the approach – one physical server = one application. The number of isolated applications independent of each other is increasing without additional hardware.
- Combining several physical servers into a pool of virtualized resources allows you to balance their load. The hardware is evenly loaded; there is no situation when one server is overloaded, and the other is idle. Running virtual machines can switch from loaded servers to less loaded ones. At the same time, the uninterrupted operation of the system also increases: the failure of one server in the cluster does not lead to the shutdown of applications; the load on other servers increases proportionally.
- Scaling IT systems without virtualization most often means purchasing or decommissioning additional servers and moving applications to servers of a different capacity. When scaling a virtual IT infrastructure, you can add virtual machines in an amount that allows the capacity of physical servers and change the capacity of already running VMs. When the capabilities of real servers are exhausted, new ones are added to the pool of virtualized physical resources: they buy more hardware. At the same time, scaling occurs without delay for application migration (downtime) – the pool of physical resources available to virtual machines increases immediately.
How Did You Move From Virtualization To Cloud Technologies?
Virtualization has become the basis for the emergence of cloud computing – a new way of consuming computing resources in which the provider of resources and their user participate. The IT department acts as a “provider,” and everyone else acts as a user in a private cloud.
Under this model, public cloud providers lease resources to users for a specific time; users usually pay only for the time of use (pay-as-you-go payment model). In private corporate clouds, company divisions and various services can reserve resources from a shared pool in the same way, only without actual payment.
The word “cloud” itself refers to a pool of virtualized resources provided to the consumer by the provider for use.
For the technical organization of the cloud, above the hypervisor and under the set of virtual machines, they have special software (a cloud platform, such as OpenStack), abstracting the VM not only from the hardware but also from the hypervisors.
This allows you to share different hypervisors in one IT infrastructure, which are usually incompatible with each other. And also combine all virtual resources into a single pool with a centralized interface for management, distribution, and control.
It turns out that virtualization is a bridge to the transition to the clouds. And cloud platforms open up new opportunities for using virtual IT infrastructure. For example, you can organize access to resources for multiple users, host isolated projects on different hypervisors, and combine different hypervisors under common control. This is the task of the provider.
Cloud platforms help companies flexibly manage their IT infrastructure and scale it instantly. At the user’s request, as many resources as needed by the company’s applications are allocated. This allows you to maintain uninterrupted operation even under changing loads.