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What is virtualization?
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Virtualization is the process of running multiple operating systems (OSs) simultaneously on a single physical computer by creating virtual machines (VMs).
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What is a hypervisor?
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A hypervisor is software that lets multiple operating systems run simultaneously on one computer by creating and managing virtual machines.
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What are the two main types of hypervisors?
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(a) Type 1 Hypervisor (Bare Metal) and (b) Type 2 Hypervisor (Host-based)
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Give an example of a Type 1 hypervisor.
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VMware ESXi, Microsoft Hyper-V, and Citrix XenServer are examples of Type 1 hypervisors.
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Give an example of a Type 2 hypervisor.
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Oracle VirtualBox, VMware Workstation, and Parallels Workstation are examples of Type 2 hypervisors.
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What are the requirements for a Type 2 hypervisor?
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A Type 2 hypervisor requires a compatible host OS and sufficient resources to run the host OS, hypervisor, and guest OSs.
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What are the requirements for a Type 1 hypervisor?
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A Type 1 hypervisor is installed directly on hardware, requiring resources to run the hypervisor and guest OSs without a host OS.
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What are some common uses for virtualization?
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(a) Testing and development, (b) Sandboxing to test malware, (c) Supporting legacy software, (d) Cross-platform testing, and (e) Training environments
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What is sandboxing in virtualization?
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Sandboxing refers to creating isolated environments (VMs) to safely test potentially harmful software like viruses or malware without affecting the main system.
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How does virtualization support legacy software?
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Virtualization allows older OSs to run as VMs on modern hardware, enabling businesses to access older applications that are incompatible with newer OSs.
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What is cross-platform virtualization?
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Cross-platform virtualization allows developers to test applications across different operating systems (e.g., Windows, Linux) within virtual machines.
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How does virtualization help in training environments?
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Virtualization allows students or employees to practice using real operating systems and software within a virtual lab. VMs can be reset after each session, ensuring a consistent environment for the next user.
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What is server-side virtualization?
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Server-side virtualization allows running multiple server roles as virtual machines on a single physical machine to improve hardware utilization.
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What is the main benefit of server-side virtualization?
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It optimizes hardware usage by consolidating multiple server roles onto one machine, reducing the need for additional physical servers.
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What is application virtualization?
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Application virtualization allows users to access and run applications hosted on a server, either by streaming or running them locally, ensuring that all users are running the latest version.
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What are some examples of application virtualization solutions?
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Citrix XenApp, Microsoft App-V, and VMware ThinApp are popular application virtualization solutions.
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What is container virtualization?
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Container virtualization isolates resources at the OS level, creating containers that run separate processes using the same OS kernel but are isolated from each other.
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What are the benefits of container virtualization?
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Containers provide lightweight isolation, allowing multiple applications or processes to run in isolated environments on the same OS kernel.
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What is an example of container virtualization software?
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Docker is one of the most widely used container virtualization platforms.
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What CPU technologies enhance virtualization performance?
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(a) Intel VT-x (Intel Virtualization Technology) and (b) AMD-V (AMD Virtualization)
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What is Second Level Address Translations (SLAT) in virtualization?
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SLAT improves virtual memory performance when running multiple virtual machines. Intel implements SLAT as Extended Page Table (EPT), and AMD implements it as Rapid Virtualization Indexing (RVI).
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Why are virtualization extensions important for CPUs?
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Virtualization extensions, such as Intel VT-x or AMD-V, improve the performance of virtual machines by allowing hardware-assisted virtualization.
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Why are multiple CPU resources important in virtualization?
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Multiple CPUs, cores, or HyperThreading significantly improve performance, especially when running multiple guest OSs simultaneously.
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Can a 32-bit hypervisor support 64-bit guest OSs?
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No, a 32-bit hypervisor cannot support 64-bit guest OSs, but a 64-bit hypervisor can support both 32-bit and 64-bit guest OSs.
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How much RAM is needed for running a guest OS on a virtual machine?
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Each guest OS requires its own memory in addition to the host OS. For example, Windows 10 requires at least 2 GB of RAM, so running a Windows 10 guest OS would require at least 4 GB total (2 GB for the host and 2 GB for the guest).
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How much disk space does a typical VM require?
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A typical Windows VM may require around 20 GB of disk space, depending on the installation and configuration.
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What are dynamically expanding disk images in virtualization?
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Dynamically expanding disk images only take up storage as the guest OS adds files, reducing initial disk space usage.
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What is the purpose of snapshots in virtualization?
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Snapshots save the state of a VM at a specific point in time, allowing users to roll back to that state if needed.
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What is the role of a Storage Area Network (SAN) in virtualization?
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A SAN allows virtual machines to store disk images in a high-speed network, bypassing local disk storage limits and offering greater capacity and performance.
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How does networking work in virtualized environments?
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Hypervisors create a virtual network where VMs can communicate with each other and the host. Advanced virtual platforms support configuring virtual switches and routers.
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How should guest OSs be secured in a virtual environment?
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Guest OSs should be patched regularly, protected against malware, and use virtualization-specific security solutions to prevent performance issues.
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What is VM sprawl?
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VM sprawl refers to the uncontrolled creation of virtual machines, leading to security risks and difficulty in managing VMs.
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How should VM images be secured?
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VM images should be developed in secure environments and monitored for unauthorized changes to prevent the introduction of malicious code, such as backdoors or logic bombs.
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Why is host security critical in virtualization?
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The host machine supports multiple guest OSs, so if it fails or is compromised, all guest OSs running on it may also be affected.
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What is VM escaping in virtualization?
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VM escaping occurs when malware in a guest OS gains access to other guest OSs or the host system.
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Why is it important to patch the hypervisor?
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Patching the hypervisor addresses vulnerabilities and prevents security issues like VM escaping.