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

 LXC and Docker are both container technologies that use Linux kernel features to create isolated environments for running applications. The main mechanisms that they use are:

• Linux Capabilities: These are a set of privileges that can be assigned to processes to limit their access to certain system resources or operations. For example, a process with the CAP_NET_ADMIN capability can perform network administration tasks, such as creating or deleting network interfaces. Linux capabilities allow containers to run with reduced privileges, enhancing their security and isolation.
• Kernel Namespaces: These are a way of creating separate views of the system resources for different processes. For example, a process in a mount namespace can have a different file system layout than the host or other namespaces. Kernel namespaces allow containers to have their own network interfaces, process IDs, user IDs, and other resources, without interfering with the host or other containers.
• Control Groups: These are a way of grouping processes and applying resource limits and accounting to them. For example, a control group can limit the amount of CPU, memory, disk I/O, or network bandwidth that a process or a group of processes can use. Control groups allow containers to have a fair share of the system resources and prevent them from exhausting the host resources.

POSIX ACLs and file system permissions are not mechanisms used by LXC and Docker to create containers. They are methods of controlling the access to files and directories on a file system, which can be applied to any process, not just containers.

References:

• LXC vs Docker: Which Container Platform Is Right for You?
• LXC vs Docker: Why Docker is Better in 2023 | UpGuard
• What is the Difference Between LXC, LXD and Docker Containers
• lxc - Which container implementation docker is using - Unix & Linux Stack Exchange

 The command vagrant init is used to initialize the current directory to be a Vagrant environment by creating an initial Vagrantfile if one does not already exist1. The Vagrantfile contains the configuration settings for the Vagrant box, such as the box name, box URL, network settings, synced folders, provisioners, etc. The command vagrant init does not execute any provisioning tool, start any box, install Vagrant on a Linux host, or download any box. Those actions are performed by other Vagrant commands, such as vagrant provision, vagrant up, vagrant install, and vagrant box add, respectively. References:

• 1: vagrant init - Command-Line Interface | Vagrant | HashiCorp Developer

 The command virsh list is used to list all running domains (VMs) on the current host. The command virsh list --all can be used to list both active and inactive domains. The other options are not valid virsh commands. The command virsh list is a basic command that lists all running domains (VMs). You can also list all configured VMs by adding the --all option. This is useful if you want to see all VMs configured in the target hypervisor that you can use on subsequent commands1. References:

• 1: 8 Linux virsh subcommands for managing VMs on the command line | Enable Sysadmin.