14.2 Virtualization Technologies
4 min read•july 30, 2024
Virtualization technologies are the backbone of , enabling efficient resource utilization and flexibility. They create software-based representations of computing resources, allowing multiple virtual instances to run on a single machine, improving hardware usage and reducing costs.
In cloud environments, virtualization facilitates multi-tenancy, rapid provisioning, and pay-as-you-go models. It supports various techniques like hardware, software, and network virtualization, each offering unique benefits for different use cases in cloud computing infrastructures.
Virtualization in Cloud Computing
Concept and Role of Virtualization
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- Virtualization creates software-based representations of computing resources (servers, storage, networks, applications)
- Enables efficient utilization of physical hardware by running multiple virtual instances on a single machine
- Hypervisors (Virtual Machine Monitors) manage and control virtual machines, allocating resources and isolating environments
- Provides benefits
- Improved hardware utilization
- Easier IT resource management
- Enhanced
- Reduced data center operation costs
- Underpins cloud service models (IaaS, PaaS, SaaS) to deliver on-demand computing resources
- Enables key cloud computing characteristics
- Rapid elasticity
- Measured service
Cloud Computing Integration
- Abstracts and dynamically allocates resources in cloud environments
- Facilitates multi-tenancy allowing multiple users to share physical infrastructure securely
- Enables rapid provisioning and de-provisioning of resources in response to demand
- Supports pay-as-you-go pricing models by allowing fine-grained resource allocation
- Enhances disaster recovery and business continuity through easy replication and migration of virtual environments
- Enables hybrid cloud deployments by providing consistent environments across on-premises and cloud infrastructure
Virtualization Techniques
Hardware Virtualization
- Creates virtual machines behaving like real computers with their own operating systems
- Managed by a ( ESXi, Microsoft Hyper-V)
- Categorized into full virtualization, paravirtualization, and hardware-assisted virtualization
- Full virtualization provides complete hardware abstraction (VMware Workstation)
- Paravirtualization requires modified guest OS for better performance (Xen)
- Hardware-assisted virtualization leverages CPU features for efficient virtualization (Intel VT-x, AMD-V)
- Enables strong between virtual machines
- Supports running different operating systems on the same physical hardware
Software Virtualization
- Creates isolated environments within a single operating system
- Allows multiple applications to run in separate containers or virtual environments
- Container-based virtualization (Docker, Kubernetes)
- Shares the host OS kernel
- Provides lightweight isolation
- Faster startup times compared to
- Lower resource overhead
- isolates applications from the underlying OS (Microsoft App-V)
- Runtime virtualization creates a virtual machine for a specific programming language (Java Virtual Machine)
Network Virtualization
- Abstracts network resources, creating virtual networks decoupled from physical infrastructure
- Enables software-defined networking (SDN) for programmable network control
- Network Function Virtualization (NFV) replaces dedicated network appliances with software on standard hardware
- Virtual LANs (VLANs) segment networks logically without changing physical topology
- Virtual Private Networks (VPNs) create secure tunnels over public networks
- Overlay networks (VXLAN, NVGRE) extend Layer 2 networks across Layer 3 boundaries
Virtualized Environments
Core Components
- Hypervisor () manages and allocates resources to virtual machines
- Type 1 (bare-metal) hypervisors run directly on hardware (VMware ESXi, Microsoft Hyper-V)
- Type 2 hypervisors run on top of a host operating system (Oracle VirtualBox, VMware Workstation)
- Virtual machines (VMs) run their own operating systems and applications, sharing physical hardware resources
- Virtual networking components enable communication
- Virtual switches connect VMs within a host
- Virtual Network Interface Cards (vNICs) provide network connectivity to VMs
- Storage virtualization technologies abstract and pool physical storage resources
- Virtual Storage Area Networks (vSANs)
- Software-defined storage solutions (VMware vSAN, Ceph)
Management and Features
- Resource management tools and APIs allow programmatic control and monitoring
- VMware vCenter, Microsoft System Center Virtual Machine Manager
- capabilities move running VMs between physical hosts without downtime
- VMware vMotion, Microsoft Live Migration
- Nested virtualization runs hypervisors within VMs for complex testing environments
- High availability features ensure VM uptime (VMware HA, Hyper-V Failover Clustering)
- Backup and disaster recovery solutions designed for virtualized environments
- Veeam Backup & Replication, Zerto
Virtualized System Performance
Resource Management
- CPU scheduling in virtualized systems balances performance and utilization
- Time-slicing allocates CPU time to VMs
- CPU pinning assigns specific VMs to particular physical cores
- Memory management optimizes usage and reduces overhead
- Ballooning dynamically adjusts VM memory allocation
- Page sharing identifies and consolidates identical memory pages
- Memory compression reduces memory footprint
- I/O virtualization reduces performance overhead for storage and network access
- Paravirtualized drivers improve I/O performance (VMware VMXNET3, Hyper-V Synthetic drivers)
- Single Root I/O Virtualization (SR-IOV) allows direct hardware access for improved performance
Performance Optimization
- Resource contention can lead to performance degradation
- Requires careful allocation and monitoring of CPU, memory, storage, and network resources
- Performance monitoring and profiling tools identify bottlenecks
- VMware vRealize Operations, Microsoft Performance Monitor
- Quality of Service (QoS) mechanisms ensure fair resource distribution
- Resource pools in VMware vSphere
- Hyper-V resource controls
- Capacity planning analyzes usage patterns and predicts future resource needs
- VMware Capacity Planner, Microsoft Assessment and Planning Toolkit
- Performance tuning techniques
- Right-sizing VMs to match workload requirements
- Optimizing virtual machine settings (virtual hardware versions, NUMA awareness)
- Implementing caching solutions for improved storage performance (VMware vSphere Flash Read Cache)
Key Terms to Review (18)
Application virtualization: Application virtualization is a technology that allows applications to run in a virtual environment, separated from the underlying operating system and hardware. This separation enables applications to be accessed remotely, installed without traditional methods, and run on various devices without compatibility issues. It enhances flexibility, security, and resource management while reducing conflicts between applications.
Cloud Computing: Cloud computing refers to the delivery of computing services—including storage, processing power, and applications—over the internet, allowing users to access and manage resources remotely. This technology has transformed how businesses and individuals operate by enabling scalability, flexibility, and cost efficiency, which connects to various technological advancements and application scenarios.
Hardware virtualization: Hardware virtualization is a technology that allows multiple operating systems to run on a single physical machine by abstracting the hardware resources. This process involves creating virtual machines (VMs) that operate independently, each with its own operating system and applications. Hardware virtualization enhances resource utilization, improves scalability, and provides a secure environment for running different workloads without interference.
Hypervisor: A hypervisor is a virtualization layer that enables multiple operating systems to run concurrently on a host machine by managing the distribution of hardware resources among these systems. It plays a crucial role in enabling server virtualization, allowing for efficient resource allocation, isolation, and security between virtual machines (VMs) on the same physical hardware. Hypervisors can operate in two modes: Type 1 (bare-metal) which runs directly on the hardware, and Type 2 (hosted) which runs on top of an existing operating system.
Isolation: Isolation refers to the separation and protection of different computing environments to ensure that they do not interfere with each other. This concept is crucial in virtualization technologies as it allows multiple virtual machines to operate on a single physical machine without affecting each other's performance or security. Isolation ensures that faults, crashes, or security breaches in one virtual environment do not propagate to others, maintaining system stability and integrity.
KVM: KVM, or Kernel-based Virtual Machine, is a virtualization technology integrated into the Linux kernel that allows the host machine to run multiple isolated virtual environments, known as virtual machines (VMs). KVM turns the Linux kernel into a hypervisor, providing capabilities for running different operating systems on a single physical machine while ensuring efficient resource management and isolation between VMs.
Live migration: Live migration is the process of moving a running virtual machine (VM) from one physical host to another without disrupting the service provided by the VM. This technique is essential in virtualization technologies, as it allows for load balancing, maintenance, and resource optimization while ensuring minimal downtime for applications and users.
Open virtualization format (ovf): Open Virtualization Format (OVF) is an open standard for packaging and distributing virtual appliances or virtual machines. OVF simplifies the process of deploying and sharing virtualized software by providing a standard way to define the properties and requirements of a virtual machine, making it easier to move and manage these resources across different virtualization platforms.
Resource pooling: Resource pooling is the practice of combining multiple resources, such as computing power, storage, and network bandwidth, into a shared pool that can be dynamically allocated to meet varying demands. This concept is fundamental in virtualization technologies, enabling efficient use of resources by allowing multiple users or applications to share the same physical infrastructure while isolating their environments for security and performance.
Sandboxing: Sandboxing is a security mechanism used to run programs in a restricted environment to prevent them from affecting the host system or accessing sensitive data. It isolates applications, allowing them to execute while minimizing their ability to interact with the rest of the system, which enhances security and stability. This method is crucial in virtualization technologies where applications may need to be tested or executed without risking damage to the underlying infrastructure.
Scalability: Scalability refers to the ability of a system, network, or process to handle a growing amount of work or its potential to be enlarged to accommodate that growth. It is crucial for ensuring that performance remains stable as demand increases, making it a key factor in the design and implementation of parallel and distributed computing systems.
Server consolidation: Server consolidation is the process of combining multiple server resources into fewer servers to optimize resource utilization, reduce costs, and improve efficiency. This technique often utilizes virtualization technologies to allow multiple virtual machines to run on a single physical server, thus maximizing the use of available hardware while minimizing energy consumption and space requirements.
Snapshot: A snapshot is a point-in-time copy of a virtual machine's disk state, memory state, and system settings that can be used for backup or recovery purposes. It allows users to capture the current state of a virtual machine so they can revert to it later if needed, making it an essential feature in virtualization technologies for data protection and system management.
Type 1 Hypervisor: A Type 1 hypervisor, also known as a bare-metal hypervisor, is a virtualization platform that runs directly on the host's hardware without needing an underlying operating system. This allows for better performance, scalability, and resource management compared to Type 2 hypervisors, which run on top of an existing operating system. Type 1 hypervisors are commonly used in data centers and enterprise environments to efficiently manage virtual machines.
Type 2 hypervisor: A type 2 hypervisor, also known as a hosted hypervisor, is a virtualization layer that runs on top of an existing operating system, enabling the creation and management of virtual machines. Unlike type 1 hypervisors that run directly on hardware, type 2 hypervisors rely on the host OS for resource management and device interaction. This setup allows for easier installation and integration within systems where users may already have a primary operating system in place.
Virtual machine disk (vmdk): A virtual machine disk (VMDK) is a file format that represents a virtual hard disk used by virtual machines, enabling the storage of the operating system, applications, and data. VMDKs are crucial in virtualization technologies as they allow multiple virtual machines to share the same physical hardware while maintaining isolated environments, thus optimizing resource usage and providing flexibility in managing workloads.
Virtual Machine Monitor: A Virtual Machine Monitor (VMM), also known as a hypervisor, is software that creates and runs virtual machines by allowing multiple operating systems to share a single hardware host. It acts as an intermediary between the virtual machines and the physical hardware, managing resource allocation, isolation, and execution of the guest operating systems. The VMM is essential in virtualization technologies, enabling efficient use of hardware resources and providing flexibility for software deployment and testing.
Vmware: VMware is a leading provider of virtualization technology that allows multiple operating systems to run on a single physical machine as virtual machines. This technology enables better resource utilization, improved scalability, and easier management of IT environments, making it a crucial element in modern data centers and cloud computing solutions.