305-300 Exam Dumps : LPIC-3: Virtualization and Containerization - Exam 305, version 3.0

The CPU flag that indicates the hardware virtualization capability on an AMD CPU is SVM. SVM stands for Secure Virtual Machine, and it is a feature of AMD processors that enables the CPU to run virtual machines with hardware assistance. SVM is also known as AMD-V, which is AMD’s brand name for its virtualization technology. SVM allows the CPU to support a hypervisor, which is a software layer that creates and manages virtual machines. A hypervisor can run multiple virtual machines on a single physical machine, each with its own operating system and applications. SVM improves the performance and security of virtual machines by allowing the CPU to directly execute privileged instructions and handle memory access, instead of relying on software emulation or binary translation. SVM also provides nested virtualization, which is the ability to run avirtual machine inside another virtual machine. To use SVM, the CPU must support it and the BIOS must enable it. The user can check if the CPU supports SVM by looking for the svm flag in the /proc/cpuinfo file or by using the lscpu command. The user can also use the virt-host-validate command to verify if the CPU and the BIOS are properly configured for hardware virtualization123. References:

How to check if CPU supports hardware virtualization (VT technology)1

Processor support - KVM3

How to Enable Virtualization in BIOS for Intel and AMD4

 The Linux kernel module that must be loaded in order to use QEMU with hardware virtualization extensions is KVM (Kernel-based Virtual Machine). KVM is a full virtualization solution that allows a user space program (such as QEMU) to utilize the hardware virtualization features of various processors (such as Intel VT or AMD-V). KVM consists of a loadable kernel module, kvm.ko, that provides the core virtualization infrastructure and a processor specific module, kvm-intel.ko or kvm-amd.ko. KVM must be loaded into the kernel of the host system in order to use the virtualization extensions of the host system’s CPU. This enables QEMU to run multiple virtual machines with unmodified Linux or Windows images, each with private virtualized hardware. KVM is integrated with QEMU, so there is no need to load it into the kernel of each virtual machine or the first virtual machine. KVM also does not require paravirtualization, which is a technique that modifies the guest operating system to communicate directly with the hypervisor, bypassing the emulation layer. References:

Features/KVM - QEMU

Kernel-based Virtual Machine

KVM virtualization on Red Hat Enterprise Linux 8 (2023)

The WORKDIR instruction sets the working directory for any subsequent RUN, CMD, ENTRYPOINT, COPY and ADD instructions that follow it in the Dockerfile1. The RUN instruction executes commands in a new layer on top of the current image and commits the results2. The RUN cd command does not change the working directory for the next RUN instruction, because each RUN command runs in a new shell and a new environment3. Therefore, the file test is created in the root directory (/) of the container image, not in the /tmp directory. References:

Dockerfile reference: WORKDIR

Dockerfile reference: RUN

difference between RUN cd and WORKDIR in Dockerfile