A virtual machine (VM) is a software program that creates a virtualized computing environment, allowing you to install an operating system and applications just like a physical computer. Virtual machines provide flexibility, security, and cost savings over dedicated hardware.
This step-by-step guide will cover:
- What is a virtual machine
- Benefits of virtual machines
- Types of virtualization
- Getting started with virtualization software
- VMware Workstation Pro
- Oracle VirtualBox
- Microsoft Hyper-V
- Creating a virtual machine from ISO
- Setting up memory and networking
- Installing the guest OS
- Key takeaways
What is a Virtual Machine
A virtual machine acts like a physical computer, but it shares the underlying physical resources of the host computer. The virtual machine contains its own virtual CPU, RAM, hard drive, and network interface card which map to the physical resources on the host. This isolation allows each VM to run its own operating system and applications independently like a stand-alone computer.
VMs are created and managed by virtualization software called hypervisor. The hypervisor allocates hardware resources dynamically to ensure VMs get what they need when they need it. Multiple VMs can run in parallel on a single host since the hypervisor can manage resource sharing efficiently.
Some key capabilities provided by virtual machines are:
- Isolation – Apps running in one VM are isolated and cannot directly access or tamper with apps in another VM.
- Encapsulation – The VM simulates a complete hardware environment allowing you to install and boot an OS in each VM.
- Flexibility – You can create, copy, share and save VM images quickly. Hardware configuration like network interfaces can be changed easily as well.
- Cost efficiency – Multiple VMs can consolidate server hardware and share the resources dynamically resulting in improved hardware utilization.
- Portability – You can move VM images across physical machines without compatibility issues.
Benefits of Virtual Machines
Here are some of the key benefits of using virtual machines:
Consolidating multiple VMs onto a single server allows you to reduce hardware cost. You save by hosting more VMs per physical server which cuts overall hardware requirements.
Isolation and Security
Isolation prevents issues like server crashes and security breaches on one VM from affecting others. This improves uptime and business continuity. You can also restore a compromised VM more easily.
Flexibility and Scalability
You can resize VMs by allocating more CPU cores, RAM and storage without downtime. New VMs can be provisioned quicker compared to procuring and setting up an entire physical server.
Better Test and Development Environments
VMs provide identical software configuration which streamlines testing and troubleshooting. Developers can replicate prod environments realistically by spinning up multiple VM instances.
Improved Hardware Utilization
Since VMs share the underlying host resources efficiently, it drives up utilization leading to better RoI from data center infrastructure.
Creating standardized VM templates allows quick OS and app deployments. Patches and upgrades can be rolled out faster as well. Backup and restoration of entire VMs is also simplified.
Types of Virtualization
There are two main virtualization types:
This involves hosting multiple guest VM instances on a single host server running a hypervisor. All hardware resources of the physical server are shared virtualized into isolated VMs. VMware ESXi, Microsoft Hyper-V, Citrix XenServer are popular hypervisors.
This encapsulates an application from the operating system on which it’s installed. The app behaves like it is interfacing directly with resources but the requests are redirected transparently. Benefits include app portability and sandboxing apps from each other.
Getting Started with Virtualization Software
Here are the most popular virtualization platforms for creating VMs easily:
VMware Workstation Pro
VMware is the industry leader in commercial hypervisors. Workstation Pro is meant for professionals to run multiple operating systems as VMs on a single Windows or Linux PC.
- Supports hundreds of OSs including Linux, Windows, etc
- Snapshots to save VM states
- VM cloning and sharing
- Run 64 virtual cores and 16TB RAM per VM
- Integrated networking and storage
- Drag and drop for devices, files and networks
VirtualBox is a powerful open-source and free hypervisor to run VMs on desktop computers. Developed by Oracle, it supports Windows, Linux, macOS, Solaris hosts.
- Free with open source license
- Easy to install with good documentation
- GUI makes it easy to manage VMs
- Imports VMs from other formats
- Headless mode for server deployments
- Extension packs for added capabilities
Hyper-V is Microsoft’s native hypervisor bundled with Windows. It virtualizes servers efficiently and has tight integration with Windows-based infrastructure.
- Available free on Windows OS
- Tightly integrated with Windows Server and can manage large environments
- Live Migration to move running VMs across hosts
- Dynamic Memory to balance RAM across VMs
- Replica VMs across hosts for better DR
Creating a Virtual Machine from ISO
An ISO image contains the installation media for an operating system. Let’s go through the steps to create a new VM and install a guest OS:
Setting Up Memory and Networking
First, create the new VM and configure the memory, processors and network adapter:
- Specify a VM Name and Location to store files
- Set the Guest OS with appropriate version
- Allocate number of virtual processors
- Assign memory for the VM
- Add a network adapter connected to the right virtual network
- Configure any additional hardware like USB controllers
Tune these hardware resources based on OS requirements. Allocating more may impact VM density on the host.
Installing the Guest OS
Next, install the guest OS using the ISO image:
- Load the OS installation ISO image
- Start the VM to boot into the media for OS installation
- Go through the installation steps like keyboard language, disk partitions etc
- Complete the OS installation and restart VM with boot device set to virtual drive
- Install VM tools and extensions for better functionality
- Configure IP addressing and external access if needed
The VM is now ready to use with the installed OS. You can create new VMs from templates or existing VMs using cloning.
Here are some of the key highlights:
- Virtual machines provide isolated and flexible computing by abstracting physical resources
- Benefits include cost savings, better utilization, security and easier scaling
- Major virtualization types are server virtualization and application virtualization
- Leading platforms to run VMs are VMware, VirtualBox and Hyper-V
- Set up memory, processors, networking adequately while creating a new VM
- Boot from ISO media to launch OS installation and complete the setup
Virtual machines let you run multiple operating systems and applications cleanly isolated from each other on shared hardware resources. This provides enormous flexibility along with security and scalability benefits over physical hardware.
With hundreds of guest OSs supported, powerful hypervisors like VMware, VirtualBox and Hyper-V make it very easy to get started. You can quickly create, clone, share, and backup full VMs containing different test configurations suited for development needs. VMs have become a crucial foundation enabling rapid innovation from virtualized infrastructure to cloud computing and hybrid environments.
Q1: How is a virtual machine different from Docker containers?
Containers provide operating system level virtualization by isolating processes, while VMs virtualize an entire operating system and hardware stack. Containers share more resources and are more lightweight.
Q2: Can I run Mac OS X as a VM on Windows?
No, Apple’s licensing does not allow running Mac OS X as a VM on non-Apple hardware. Hackintosh builds violate this.
Q3: Do virtual machines provide good performance for apps?
It depends. CPU and memory-intensive apps can run well. But graphics, database and networking apps may see some overhead. Choose workloads accordingly.
Q4: What VM software is best for home users?
VMware Workstation Player (free) and Oracle VirtualBox are both easy to use for home users while being powerful for running different home lab VMs.
Q5: How do I backup and restore virtual machines?
Hypervisors provide snapshotting capability to easily backup VM state. VMs can also be exported as files or cloned for backup purposes and restored.
Q6: Can I convert a physical server into a virtual machine?
Yes, through a process called physical-to-virtual (P2V) conversion. Popular tools are VMware Converter and Microsoft Virtual Machine Converter.
Q7: Do I need hardware virtualization support to run VMs?
Modern CPUs have hardware acceleration which speeds up VM performance significantly, so it is recommended. VirtualBox and VMware automatically detect its availability.
Q8: Is GPU passthrough possible with VMs?
Yes, hypervisors allow mapping a dedicated graphics card to a single VM. This provides near-native gaming graphics performance to the VM using the GPU.
Q9: What are the minimum system requirements to run VMs effectively?
You would need at least 4 GB RAM, multi-core processor for virtualization support, SSD storage. More resources allow you to manage more VMs comfortably.
Q10: Can I migrate VMs from one vendor’s hypervisor to another?
While technically possible, there may be compatibility issues. Reinstalling the OS from scratch is easier. Migration tools also exist to simplify this process across hypervisors.
Q11: Do I need an enterprise hypervisor license for personal use VMs?
No, free hypervisors like VirtualBox work well enough for personal use. Some paid versions like VMware Workstation are affordable for individuals.
Q12: How do I connect peripheral devices to VMs?
The VM settings allow you to map host machine’s USB ports, hardware disks, sound cards etc to appear as virtual devices attached to the guest VM OS.
Q13: Can I run Docker inside a VM?
Yes, nested virtualization allows running Docker and managing containers inside a VM. This adds an extra layer of isolation for containerized apps.
Q14: How to optimize storage performance for virtual machines?
Use high speed storage like SSD disks. Leverage host caching. Ensure the guest OS uses appropriate disk controllers and drivers.
Q15: What is virtual networking and how do VMs connect to external networks?
Software Ethernet adapters connect VMs in an internal virtual network. Bridged mode adapters map physical NICs into VMs allowing external connectivity.
Q16: Can I limit resources like CPU and RAM for VMs?
Yes, hypervisors allow capping resource shares allocated per VM, so you can optimize utilization levels based on priorities across VMs.
Q17: What is virtualization technology like VT-x and AMD-V?
These are hardware extensions in modern CPUs for accelerating hypervisor functionality related to virtual memory and power management ultimately boosting VM performance.
Q18: How can I monitor resource usage of virtual machines?
Hypervisors provide detailed historical tracking of utilization metrics like CPU, memory for each VM. This helps analyze and troubleshoot any resource contention issues.
Q19: What is virtual machine high availability (HA)?
It protects against host failures. If a host crashes, affected VMs can be automatically restarted on other available hosts. This reduces downtime.
Q20: Can I install Linux distros easily on VMs?
Yes, hypervisors make it very easy to spin up new Linux VMs instantly from library of operating system templates without going through manual installation.