Virtual machines (VMs) typically refer to separate OS installations on a single computer, with each OS having a share of the computer’s system resources. As an example, a Linux VM may be installed on top of your Windows PC. Several OS installations can coexist on the same physical machine at the same time, so long as the machine has capable enough hardware. This makes VMs a convenient way to extend your desktop and server environments. Other benefits of VMs include easy provisioning and maintainability, and high availability.
- Definitions of Virtualization and Virtual Machines
- Benefits of Virtual Machines
- Containers: An Alternative to Virtual Machines
- Benefits of Virtual Machines over Containers
- Managing VDI with Parallels RAS
Definitions of Virtualization and Virtual Machines
Virtualization uses software to simulate computer hardware, creating a virtual system. Applications, servers, storage and networks can all be virtualized.
Virtualization came about as a way to consolidate servers. Before virtualization, you saw many datacenters filled with servers running different operating systems and applications. With virtualization, it is now possible to store multiple operating systems and applications on a single server. Thus, the number of servers in today’s datacenters are fewer than before.
VMs refer to virtual computer systems where other operating systems and applications reside. VMs are self-contained and completely independent from the physical hardware that serves as their host machine. Multiple VMs, or guest machines, can be installed on a host.
A software known as a hypervisor sits between the VMs and the host and is responsible for allocating the computing resources of the host to VMs. Hypervisors can either be type-1 or type-2 hypervisors. Type-1 hypervisors run directly on the host’s hardware; Type-2 hypervisors run atop the hardware’s OS. Microsoft Hyper-V is an example of a type 1 hypervisor; Parallels® Desktop for Mac is a type-2 hypervisor.
Other characteristics of VMs include:
- A single server can host many VMs, with the hypervisor allotting its share of the server’s system resources to each VM.
- Each VM is isolated and performs independently from the rest of the hardware.
- The state of a VM can be saved to a file, and VMs can be moved and copied as if they are files.
- VMs are not tied down to any server; instead, they can be migrated easily to another server.
Benefits of Virtual Machines
There are many benefits to using virtual machines in your organization, including the following:
Before virtualization, organizations spent a significant percentage of their IT spending on acquiring physical servers for hosting applications. As virtualization gained headway, organizations shifted to buying more robust hardware that could accommodate more virtual systems. This is significantly less costly than buying more hardware. Moreover, you can extend the life of old software with VMs.
It can take hours or days to replace physical servers hit by a disastrous event. In contrast, virtualized environments take only minutes to bring up again, since you can always replicate or clone them.
IT teams are more productive since they have to maintain only the host machines. For traditional datacenters that have not yet moved to a virtualized environment, hardware maintenance is more tedious.
Maintenance operations have minimal impact on your production environment. In many cases, there is no need for downtime when performing maintenance. In addition, VMs allow for simplified testing and development processes for applications and websites.
Environment-friendly IT operations
The fewer the number of servers, the more you save in terms of power consumption. This leads to lower operating expenses for you and less carbon footprint from your datacenter.
Containers: An Alternative to Virtual Machines
Containers are contained within a single OS installation, unlike VMs that run on their own OS. They share the host OS kernel and resources, including binaries and libraries. They are also standalone and lightweight and take only seconds to boot up, whereas VMs are far heavier and can take a minute or more to start.
Since they are smaller in size, you can put more applications on a single server with a container, compared to a VM. They are also ideal for use in development, testing and deployment since you can essentially have the same container operating across these environments.
Linux Containers (LXC) and Docker are two of the more popular types of containers. With LXC, you can run several Linux systems on a single host. Docker extended LXC by making containers more portable and flexible, and has since become the leading container runtime environment for managing containers.
Containers have their own benefits, including lower memory requirements, reduced snapshot sizes, native-level performance and quicker deployment times.
Benefits of Virtual Machines over Containers
While containers are newer and have their own advantages, virtual machines are still preferred for the following reasons:
Full isolation means more security
Communications between the guest OS and the host go through the hypervisor and are thus more secure. Since containers remain in the host OS, they are more susceptible to security flaws in the OS.
Portability means that VMs can run old applications better
VMs are standalone and portable—they can be copied and cloned between hosts. To run old applications, you need only to have a guest OS that supports the application. In the case of containers, there is no chance of an older application running if it isn’t supported by the host OS.
Better resource allocation means better ability to run resource-intensive applications
VMs can run resource-intensive applications better since the host allocates them with their own resources. Containers share limited resources—the more containers there are in a host, the smaller the resources allotted to the container.
Versatility means the ability to allocate persistent storage
VMs can be set to store persistent data if required. Containers are ephemeral in nature. You need complex storage solutions for a container to handle persistent storage.
Managing VDI with Parallels RAS
Parallels® Remote Application Server (RAS) allows easy and flexible management of virtual desktop infrastructure (VDI) solutions. With Parallels RAS, persistent and non-persistent VDI is possible.
Parallels RAS supports a wide number of hypervisors, including Microsoft Hyper-V, VMware ESXi, Scale Computing HC3 and Nutanix Acropolis. It is ideal for building an infrastructure ready for multi-cloud using on-premises and cloud solutions, or a combination of the two.
You can use over 130 built-in, automated optimization capabilities in Parallels RAS to ensure efficient and streamlined delivery of virtual applications and desktops across your organization. You can also set a preconfigured number of VMs to be created based on a RAS template so that enough VDI instances are available for your users at all times.
Parallels RAS gives administrators more flexibility when managing vast numbers of guest VMs through the use of VM pools. Multiple pools based on guest VMs from specific RAS templates can be set, allowing segregated access to applications when required.
Check out how Parallels RAS can help manage your VDI by downloading the trial.