Virtual Machine (VM)
What is a virtual machine (VM)?
A virtual machine (VM) is a program running on host hardware that provides an isolated environment with its own guest operating system (OS) and applications, separate from the host OS or any other VMs running on the host system.
Virtual Machines Operate Identical to Physical Hardware
From an end user’s perspective, a VM provides nearly the same experience as a single-computer environment. Files and applications can be loaded, stored, updated, and worked with in the same way as they would on a physical (i.e., bare metal) computer, without affecting the host system or any other VMs. The physical resources of the host system—such as CPU, GPU, memory, and storage—are allocated to the VM by a software layer called the hypervisor. The virtual hardware devices provided by the hypervisor map to physical hardware on the host system (e.g., a VM’s virtual hard disk is stored as a file on the host hard drive).
VMs are Separate from the Hardware for a reason
Virtual machines have several practical applications. Because they separate the virtual operating environment from the physical hardware, VMs are useful for testing potentially malicious applications. Before rolling out an OS update, IT teams can test the OS on a VM to make sure critical business apps will still work with the update. VMs can also be used by dev teams to test new applications or updates on a range of OSes and versions. If there is a need to run an older application that requires a legacy OS, a VM can be used to run it.
Why should you use virtual machines?
The benefits of VMs include:
- Portability: VMs can easily be moved from one server to another, or even from on-premises hardware into a cloud environment.
- Smaller footprint: Because VMs allow for more efficient use of hardware resources, fewer host machines may be needed to support the same workloads as compared to running them in a physical environment, saving space, energy, and costs.
- Faster provisioning: An existing VM can be easily duplicated when a new instance is needed, rather than having to be set up from scratch.
- Security: VMs provide a safe, sandboxed environment, so any malware or other issues affecting one specific VM are not spread to the host system or other VMs.
However, there are some trade-offs to running VMs. The administration and management of a VM environment does require some expertise from IT staff. And having a hypervisor layer and multiple OSes running on the same host system does come with a performance cost. For users who have significant performance demands, latency or resource availability issues in a VM environment may make them hesitant to work on a VM.
Virtual desktops vs. virtual machines
There are two primary ways that virtualization is used by organizations. Companies may have a mix of these two options in their network, depending on their needs.
The first option is virtual desktops. This technology creates a virtual workstation that offers a standard, shared experience across all virtual desktops on a central network. Users can easily access their virtual desktop remotely over the Internet and work on it with a consistent experience regardless of the device they use to access it. The desktop interface is limited, and users only have access to specific applications. These workstations do not use virtual hardware resources such as CPU, memory, or storage, and they are no longer active when the user logs off.
Virtual machines, on the other hand, offer a customizable virtual PC experience that does provide the user with specific hardware resources. A greater range of applications are available on VMs as compared to virtual desktops. VMs are also isolated from all other VMs on the network, and they continue to exist on the system even after the user signs off. They basically offer the same experience as a desktop PC but without the hardware maintenance.
Uses of virtual machines
Software, OS, and application testing: While software developers naturally need to test their applications in different environments, they aren’t the only type of company that may need to do so. Any organization that is looking to deploy a critical update may wish to test that update on a VM instance and identify possible incompatibilities before deploying it across their organization. Performing such tests on VMs is simpler and more cost effective than having to test on several individual physical machines.
Running legacy software: Companies may have custom or specialized applications that can’t be run in a modern OS but must still be used by the business. Users who need to run these applications can run them on an old OS from a VM.
Running software designed for a different OS: Some applications are only available for a specific platform. Additionally, certain users may have specific needs that cause them to use different hardware than the rest of the organization, but still need to access company-standard apps. In these cases, a VM can be used to run software designed for a different OS than is native to the host computer.
Running SaaS applications: Software as a service (SaaS) refers to providing software to users through the cloud. SaaS users subscribe to an application and access it over the Internet rather than purchasing it once and installing it on their computers. VMs in the cloud are typically used for both the computation for the SaaS applications as well as for delivering them to users.
Data storage and backup: Cloud-based VM services are very popular for storing files because the data can be accessed from anywhere via the Internet. Plus, cloud VMs typically offer improved redundancy, require less maintenance, and scale more easily than on-premises servers.
Hosted services: Hosting services such as access management and email on cloud VMs is generally faster and more cost effective than doing so in an on-premises data center. Running these services on cloud VMs also helps offload maintenance burdens and security concerns to the cloud provider.
What are the types of virtualizations?
Full virtualization: Full virtualization involves the creation of virtual machines to simulate the functionality of physical computers. It includes:
- Hypervisor-based virtualization: This method allows hypervisors to run directly on physical Hardware, offers direct access, and delivers high performance.
- Hardware-assisted virtualization: It allows enhanced isolation between the guest operating systems and hosts by offering support for virtualization through CPUs and hardware extensions.
Para-virtualization: Para-virtualization allows the hypervisor and guest operating systems to work together, enhancing speed and performance.
- Overview of para-virtualization: Para-virtualization facilitates interaction between the guest operating system and hypervisor to enable direct communication and resource sharing.
- Advantages and use cases of para-virtualization: Para-virtualization supports the effective utilization of resources, thereby improving scalability. It reduces the hardware emulation overhead and ensures direct communication with the hypervisor. Para-virtualization can be used in server consolidation and high-performance computing, which demand high performance and efficiency.
Containerization: Containerization creates and deploys isolated application environments known as containers, ensuring consistent and portable execution across all computing environments.
- The distinction between virtual machines and containers: Virtual machines mimic the operating system, enabling the execution of isolated instances on a single physical server. In contrast, containers share the host operating system, offering isolated runtime environments.
- Benefits and applications of containerization: Containerization offers multi-fold benefits such as isolation, efficiency, and portability. Microservices facilitate the testing and deployment of modular and scalable applications, accelerating rapid development.
What are the components of a virtual machine?
A hypervisor is a software that enables creating and managing virtual machines (VMs). It allows different frameworks to run simultaneously on a single physical host machine, sharing its underlying equipment resources.
- Definition and role of a hypervisor: A hypervisor is a medium between the actual equipment and the virtual machines running on it. It offers a deliberation layer that virtualizes the hidden equipment, permitting various VMs to work autonomously and safely. The hypervisor deals with the allotment and use of the host's resouces, such as computer chips, memory, storage, networking, and systems administration. It guarantees that each VM is allocated its reasonable portion of resources while ensuring isolation between them.
- Types of hypervisors: There are two types of hypervisors:
- Type 1: Bare-metal hypervisor: The bare-metal hypervisor runs on the host machine's Hardware without an underlying operating system. It connects to the equipment assets and administers virtualization to visitor working frameworks. This hypervisor is commonly used in server virtualization situations and offers better execution and security since no extra working framework layer exists.
- Type 2: Hosted hypervisor: A hosted hypervisor runs on top of a host working framework. It depends on the host operating system for gadget drivers and other equipment communications. Type 2 hypervisors are frequently used for work area virtualization and are simpler to set up and use. They permit clients to run various guest operating systems on their PCs.
Guest operating system
- Importance and functionality of a guest OS: The guest operating system is a pivotal part of a virtual machine (VM) as it offers the environment in which applications run. Its primary significance and usefulness inside a VM include running applications, resource management, device drivers, security and isolation, and file system management.
- Compatibility considerations with virtual machines: Some key compatibility aspects include supported guest operating systems, drivers and integration, performance and optimization, licensing, and virtualization rights.
Virtual Hardware: Virtual equipment refers to the product characterized by imitating or virtualizing actual equipment inside a virtual machine (VM) environment. It enables multiple virtual machines to share and use equipment assets efficiently. The fundamental parts of virtual equipment include:
- CPU virtualization: Abstracts and segregates the physical CPU into virtual CPUs, enabling multiple VMs to run concurrently on a physical server.
- Memory virtualization: Abstracts physical memory into virtual memory, offering efficient memory allocation and management.
- Disk and storage virtualization: Enables pooling of storage resources and provisioning of virtual disks.
- Network virtualization: Overlays virtual networks on physical networks to improve network agility and usage of network resources.
How can organizations create and manage virtual machines?
Creating a virtual machine
- Selection of hypervisor and virtualization platform: The most critical phase in creating a virtual machine is choosing an appropriate hypervisor and virtualization stage. Consider capabilities, execution, and similarity with your equipment and working frameworks.
- Configuring virtual machine settings: When configuring the virtual machines, focus on the following configurations - CPU, memory, storage, and networking.
- Installation of the guest operating system: It includes the following steps:
- Mount or attach the installation media (ISO image, installation CD/DVD) to the virtual machine's virtual optical drive.
- Turn on the virtual machine and follow the installation process of the guest OS. This involves selecting language, disk partitioning, network configuration, and other installation options.
- During the guest OS installation, provide the necessary information, such as product key or license information.
- Complete the installation process, including configuring initial settings, creating user accounts, and installing required drivers or software within the guest OS.
- Once the guest OS is installed, the virtual machine is ready. You can customize the VM settings, install additional software, and manage it through the virtualization platform's management tools.
Managing virtual machines
- Starting, stopping, and pausing virtual machines: You can start, stop, and pause virtual machines on a case-by-case basis. Through the virtualization stage's administration point of interaction or order line instruments, you can start these activities:
- Starting a virtual machine: Start the boot interaction of a virtual machine, permitting it to run and execute the visitor working framework and applications.
- Stopping a Virtual Machine: Smoothly shut down a virtual machine to close running applications and visitor working framework.
- Pausing a Virtual Machine: Stop the execution of a virtual machine, saving its state in memory.
- Snapshotting and cloning virtual machines: Snapshotting and cloning permit you to save the condition of a virtual machine and make copies for different purposes. These elements are commonly accessible through the virtualization stage's administration interface. Snapshotting takes a depiction of a virtual machine to capture VM's circle, memory, and arrangement state. Cloning makes a precise copy of a virtual machine, including its design, plate, and memory state.
- Resource allocation and management: Effective asset allocation is essential for the ideal execution and use of virtual machines. Critical parts of asset assignment include CPU allocation, memory allocation, storage allocation, and performance monitoring.
Virtual machine templates and images
- Creating and using templates: Virtual machine layouts are preconfigured and pre-installed virtual machines that act as formats for conveying new virtual machines. They are made by capturing the condition of a designed virtual machine and can be utilized as a pattern for rapidly provisioning new VMs. The process includes:
- Creating a virtual machine
- Generalizing virtual machine
- Capturing virtual machine as a Template
- Using the template
- Importing and exporting virtual machine images: Virtual machine images are files that contain info about the condition of a virtual machine, including the visitor's working framework, applications, and design. Bringing in and trading virtual machine pictures allows you to move VMs between various virtualization stages or reinforcement and reestablish VMs. The cycle involves exporting/importing a virtual machine image and compatibility considerations.
What is virtual machine networking?
Virtual networking basics
- Bridged, NAT, and host-only networking: Virtual systems administration permits virtual machines (VMs) to communicate with one another, host machines, and outer organizations. In bridged networking, the virtual machine is associated directly with the organization network through the host's network adapter. With NAT networking, virtual machines share the host's IP address and organization association. Host-only systems administration makes a confidential organization that permits virtual and host machines to correspond.
- Virtual switches and network adapters: A virtual switch is a product-based network switch that works inside the hypervisor. It interfaces virtual machines with one another and with the organization. A network adapter is a virtualized network interface that associates a virtual machine with a virtual switch. It appears as an organization network interface card inside the VM, permitting it to send and get network traffic.
Network configuration for virtual machines
- Assigning IP addresses and configuring DHCP: To arrange network availability for virtual machines, you can appoint IP addresses physically or use DHCP (Dynamic Host Setup Convention) for programmed IP address tasks. You can physically assign IP locations to each virtual machine by designing the organization settings inside the visitor working framework. DHCP sends dynamic and programmed IP address tasks to virtual machines and lessens manual arrangement efforts while conveying or altering virtual machines.
- Port forwarding and network security considerations: Port forwarding permits outer network traffic to arrive at explicit ports on a virtual machine. This is helpful for administrations, for example, web servers or distant work area access. Network security is necessary to safeguard virtual machines and the organization's environment and has safety points such as a firewall, network segmentation, network monitoring, and VPN.
Virtual machine connectivity
- Remote access and console connections: Virtual machines can be remotely accessed through different strategies (SSH, RDP, and virtual machine console), permitting clients to oversee and communicate with them.
- Integration with physical networks: Virtual machines can be coordinated with networks to permit correspondence between virtual machines and gadgets. It can be achieved through bridged networking, VLANs, VPNs, gateways, and routers.
What are the use cases and applications of virtual machines?
- Consolidating multiple servers onto a single host: Server virtualization allows combining numerous servers onto an individual host machine. Rather than committing one server for every application or responsibility, virtualization considers the production of different virtual machines (VMs) on an individual server. It offers advantages such as cost-saving, resource optimization, easy management, scalability, and flexibility.
- Load balancing and high availability: Server virtualization provides a mechanism for load balancing and high availability to guarantee persistent accessibility and productive asset use. Load balancing incorporates naturally appropriating VMs concerning asset usage, network traffic, or predefined rules. It guarantees that every host becomes overpowered while others remain underutilized. High availability refers to the capacity to keep applications and administrations running.
Development and testing environments
- Creating isolated development environments: The designers can set up devoted virtual machines for programming advancement, permitting them to work in a confined and controlled climate. The advantages of involving virtual machines for isolated environments include environment consistency, sandbox testing, isolation, security, customization, and portability.
- Testing software compatibility and scalability: Virtual machines are essential for testing software compatibility and scalability. Software developers and testers can rapidly turn up VMs with explicit arrangements to test programming similarity across different stages, programs, and adaptations. Virtual machines take into consideration simple scaling of test conditions. Testers can make different VM occasions and recreate high client loads or organization conditions to assess programming execution and adaptability.
Cloud computing and virtual data centers
- Infrastructure as a Service (IaaS) and virtual machines: IaaS is a distributed computing model that gives virtualized figuring assets over the web. Virtual machines play a massive role in IaaS and can be used for virtual machine instances, on-demand resource allocation, and multi-tenancy.
- Managing and scaling virtual machine deployments: Productive administration and scaling are pivotal for virtual machine organizations in cloud conditions. Some primary considerations include automation, orchestration, resource monitoring, auto-scaling, load balancing, backup, and disaster recovery.
- Virtual desktop infrastructure (VDI): VDI is a work area virtualization innovation that permits clients to access their desktop environments remotely from a distance or on different gadgets. VDI includes facilitating virtual machines (VMs) on a unified server foundation and conveying the work area experience to end clients over the organization. Its key components include virtual desktops, centralized management, remote access, and user profile management.
- Remote access and thin client computing: Desktop virtualization empowers remote access and thin client processing, giving a lightweight computing experience. It offers centralized data and application storage and enhanced security and data protection.
What are the challenges and considerations in virtual machine deployment?
Performance and resource management
- Overhead and performance implications of virtualization: Virtualization presents a reflection layer between the equipment and virtual machines. It is essential to consider the following overheads: CPU, memory, storage and I/O, and network overhead.
- Resource allocation and contention: Virtual machine organizations require asset distribution to guarantee ideal execution and avoid asset conflict. Key considerations include CPU and memory allocation, storage performance, and network bandwidth.
Security and isolation
- Virtual machine security best practices: To upgrade security in virtual machine arrangements, consider the following practices - patching and updates, secure configuration, isolation and segmentation, monitoring, and logging.
- Vulnerabilities and risks in virtualized environments: Virtualized conditions present explicit weaknesses and dangers, such as hypervisor vulnerabilities, VM escape, data leakage, and cross-VM attacks.
Licensing and compliance
- License considerations for virtual machines: Virtual machine arrangements might have to permit suggestions for working frameworks and applications.
- Compliance with software and hardware agreements: Virtual machine arrangements should adhere to programming and equipment arrangements, including software and hardware vendor agreements and compliance regulations.
What are the future trends in virtual machines?
- Hybrid cloud and multi-cloud environments: The eventual fate of virtual machines is intently attached to the development of hybrid cloud and multi-cloud conditions. The key trends include hybrid cloud adoption, multi-cloud deployments, interoperability, and standardization.
- Edge computing and virtualization: Edge computing brings computing assets nearer to the data source, driving the reception of virtualization at the edge with technologies such as edge virtualization and distributed application deployment.
- Serverless computing and function as a service (FaaS): The rise of serverless figuring and function as a service (FaaS) influences virtual machines through container-based serverless frameworks.
- Emerging technologies and virtual machines: Innovations such as bare metal virtualization, GPU virtualization, and quantum computing and virtualization will keep on impacting the development of virtual machines, empowering new abilities, further developing execution, and extending their relevance across different areas.
HPE virtual machine solutions
We engineer our servers for deep integration with partner operating systems and virtualization software. We also work closely with our partners to optimize, certify, and support their products in various HPE server environments. Our Partner Software portfolio delivers a variety of compelling software and virtualization solutions for hybrid and multi-cloud environments, in collaboration with software partners including Microsoft, VMware, Red Hat, and SUSE.
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