305-300 Exam Questions & Answers

Vagrant is a tool designed to automate the creation and provisioning of development virtual machines using a declarative configuration file called a Vagrantfile. According to virtualization documentation, Vagrant simplifies setting up reproducible environments by automatically installing and configuring virtual machines based on this file.

Vagrant does not perform monitoring, reporting, hypervisor functions, or automatic VM migration. It integrates with providers such as VirtualBox, KVM, and VMware but is not itself a hypervisor.

Therefore, the correct answer is A.

A container image is a static, immutable package that contains an application along with all its required dependencies, libraries, and configuration files. Containerization documentation defines a container image as a snapshot of an application and its runtime environment, which can be instantiated as a running container.

Container images do not include a full operating system kernel; instead, containers share the host system's kernel. This design makes containers lightweight and fast to deploy compared to traditional virtual machines.

Therefore, the correct answer is C.

Infrastructure as Code (IaC) is an approach where infrastructure is defined and managed using machine-readable configuration files. According to DevOps and cloud documentation, Puppet, Terraform, AWS CloudFormation, and Ansible all support IaC principles.

Terraform and AWS CloudFormation are declarative IaC tools used to provision cloud infrastructure. Puppet and Ansible are configuration management and automation tools that also enable infrastructure definition through code.

All listed tools are widely recognized in IaC workflows, making A, B, C, and D correct.

Libvirt is a toolkit that provides a common API for managing different virtualization technologies, such as KVM, Xen, LXC, and others. Libvirt allows users to configure and control various aspects of a virtual machine (also called a domain), such as its CPU, memory, disk, network, and other resources. Among the resources that can be limited by libvirt for a KVM domain are:

Amount of CPU time: Libvirt allows users to specify the number of virtual CPUs (vCPUs) that a domain can use, as well as the CPU mode, model, topology, and tuning parameters. Users can also set the CPU shares, quota, and period to control the relative or absolute amount of CPU time that a domain can consume. Additionally, users can pin vCPUs to physical CPUs or NUMA nodes to improve performance and isolation. These settings can be configured in the domain XML file under the <cpu> and <cputune> elements12.

Size of available memory: Libvirt allows users to specify the amount of memory that a domain can use, as well as the memory backing, tuning, and NUMA node parameters. Users can also set the memory hard and soft limits, swap hard limit, and minimum guarantee to control the memory allocation and reclaim policies for a domain. These settings can be configured in the domain XML file under the <memory>, <memoryBacking>, and <memtune> elements13.

The other resources listed in the question are not directly limited by libvirt for a KVM domain. File systems allowed in the domain are determined by the disk and filesystem devices that are attached to the domain, which can be configured in the domain XML file under the <disk> and <filesystem> elements14. Number of running processes and number of available files are determined by the operating system and the file system of the domain, which are not controlled by libvirt.

libvirt: Domain XML format

CPU Allocation

Memory Allocation

Hard drives, floppy disks, CDROMs

Libvirt uses XML files to store configuration data for objects in the libvirt API, such as domains, networks, storage, etc. This allows for ease of extension in future releases and validation of documents prior to usage. Libvirt does not use any of the other file formats listed in the question. Reference:

libvirt: XML Format

LPIC-3 Virtualization and Containerization: Topic 305.1: Virtualization Concepts and Theory