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Methods for creating virtual computing environments from physical resources

Core Idea: Virtualization technologies enable the creation of virtual computing resources that abstract and isolate workloads from the underlying physical hardware, allowing for more efficient resource utilization and management flexibility.

Key Elements

Types of Virtualization

• Hardware/Platform Virtualization: Creates virtual machines that run complete operating systems
  • Type 1 (Bare-metal): Hypervisors run directly on hardware (Hyper-V, VMware ESXi, KVM)
  • Type 2 (Hosted): Hypervisors run on top of an operating system (VMware Workstation, VirtualBox)
• Operating System Virtualization: Isolates applications within the same OS
  • Containers (Docker, LXC)
  • Jails (FreeBSD)
  • Zones (Solaris)
• Application Virtualization: Encapsulates applications from the underlying OS
  • Application streaming
  • Portable applications
• Network Virtualization: Creates virtual networks independent of physical network hardware
  • Virtual LANs (VLANs)
  • Software-defined networking (SDN)
• Storage Virtualization: Abstracts logical storage from physical storage devices
  • Storage Area Networks (SAN)
  • Network Attached Storage (NAS)
  • Software-defined storage

Key Virtualization Techniques

• Full Virtualization: Complete simulation of hardware to run unmodified guest OS
• Paravirtualization: Guests are modified to use special hypercalls (Enlightened IO)
• Hardware-assisted Virtualization: Uses CPU features (Intel VT-x, AMD-V) to improve performance
• Memory Virtualization: Mapping VM memory to physical memory
  • Shadow page tables
  • Second Level Address Translation (SLAT)
• I/O Virtualization: Managing access to physical I/O devices
  • Device emulation
  • Direct device assignment
  • Single Root I/O Virtualization (SR-IOV)

Key Benefits

• Resource Efficiency: Higher utilization of physical hardware
• Isolation: Security and stability through workload separation
• Flexibility: Easier provisioning, migration, and management
• Disaster Recovery: Simplified backup and replication
• Development and Testing: Consistent environments and faster provisioning

Historical Evolution

• Early mainframe partitioning (1960s-1970s)
• x86 virtualization challenges (1990s)
• VMware's software virtualization breakthrough (1999)
• Hardware virtualization extensions (mid-2000s)
• Rise of cloud computing (2010s)
• Container revolution (2013-present)

Additional Connections

• Broader Context: Cloud Computing (virtualization as enabling technology)
• Applications: Server Consolidation (primary business use case)
• See Also: Containerization (alternative to traditional VM virtualization)

References

1. "Virtualization: A Manager's Guide" by Dan Kusnetzky
2. Virtualization Technology Specifications (Intel, AMD)

#virtualization #computing #technology #infrastructure

Connections:

Sources:

• From: Hyper-V - Wikipedia