A Virtual Machine (VM) is a compute resource that uses software instead of a physical computer to run programs and deploy apps. One or more virtual “guest” machines run on a physical “host” machine. Each virtual machine runs its own operating system and functions separately from the other VMs, even when they are all running on the same host. This means that, for example, a virtual MacOS virtual machine can run on a physical PC. Show
Virtual machine technology is used for many use cases across on-premises and cloud environments. More recently, public cloud services are using virtual
machines to provide virtual application resources to multiple users at once, for even more cost efficient and flexible compute.
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Cross-Platform Development and Testing for Today’s Digital WorkspaceVirtual machines (VMs) allow a business to run an operating system that behaves like a completely separate computer in an app window on a desktop. VMs may be deployed to accommodate different levels of processing power needs, to run software that requires a different operating system, or to test applications in a safe, sandboxed environment. Virtual machines have historically been used for server virtualization, which enables IT teams to consolidate their computing resources and improve efficiency. Additionally, virtual machines can perform specific tasks considered too risky to carry out in a host environment, such as accessing virus-infected data or testing operating systems. Since the virtual machine is separated from
the rest of the system, the software inside the virtual machine cannot tamper with the host computer. The virtual machine runs as a process in an application window, similar to any other application, on the operating system of the physical machine. Key files that make up a virtual machine include a log file, NVRAM setting file, virtual disk file and configuration file. Virtual machines are easy to manage and maintain, and they offer several advantages over physical machines:
While virtual machines have several advantages over physical machines, there are also some potential disadvantages:
Users can choose from two different types of virtual machines—process VMs and system VMs: A process virtual machine allows a single process to run as an application on a host machine, providing a platform-independent programming environment by masking the information of the underlying hardware or operating system. An example of a process VM is the Java Virtual Machine, which enables any operating system to run Java applications as if they were native to that system. A system virtual machine is fully virtualized to substitute for a physical machine. A system platform supports the sharing of a host computer’s physical resources between multiple virtual machines, each running its own copy of the operating system. This
virtualization process relies on a hypervisor, which can run on bare hardware, such as VMware ESXi, or on top of an operating system. All the components of a traditional data center or IT infrastructure can be virtualized today, with various specific types of virtualization:
Like virtual machines, container technology such as Kubernetes is similar in the sense of running isolated applications on a single platform. While virtual machines virtualize the hardware layer to create a “computer,” containers package up just a single app along with its dependencies. Virtual machines are often managed by a hypervisor, whereas container systems provide shared operating system services from the underlying host and isolate the applications using virtual-memory hardware. A key benefit of containers is that they have less overhead compared to virtual machines. Containers include only the binaries, libraries and other required dependencies, and the application. Containers that are on the same host share the same operating system kernel, making containers much smaller than virtual machines. As a result, containers boot faster, maximize server resources, and make delivering applications easier. Containers have become popluar for use cases such as web applications, DevOps testing, microservices and maximizing the number of apps that can be deployed per server. Virtual machines are larger and slower to boot than containers. They are logically isolated from one another, with their own operating system kernel, and offer
the benefits of a completely separate operating system. Virtual machines are best for running multiple applications together, monolithic applications, isolation between apps, and for legacy apps running on older operating systems. Containers and virtual machines may also be used together. Virtual machines can be simple to set up, and there are many guides online that walk users through the process. VMware offers one such useful virtual machine set-up guide. Which is the most efficient way for the testing team to save costs on virtual machines?Which is the most efficient way for a testing team to save costs on virtual machines on weekends when testers are not at work? Answer : Deallocate virtual machines when they're not in use.
Which is the best way for companies to ensure that they only deploy cost effective virtual machine SKU sizes?Which is the best way for companies to ensure that they only deploy cost-effective virtual machine SKU sizes? Create a policy in Azure Policy that specifies the allowed SKU sizes. Periodically inspect the deployment manually to see which SKU sizes are used.
Which of the following is a good practice to reduce costs in Azure?Best practice: Use Azure Reserved VM Instances
Using Azure Reserved VM Instances, you prepay for either a one-year or three-year term for reserved instances. Prepayment provides a discount on the resources you use.
How much does it cost to save a VM in Azure?Buy an Azure savings plan to save money on a variety of compute services. Buy reserved virtual machine instances to save money over pay-as-you-go costs. Optimize virtual machine spend by resizing or shutting down underutilized instances. Use Standard Storage to store Managed Disks snapshots.
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