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

 The correct command to move the libvirt domain web1 from the current host system to the host system host2 is virsh migrate web1 qemu+ssh://host2/system. This command uses the virsh migrate command, which initiates the live migration of a domain to another host1. The first argument is the name of the domain to migrate, which in this case is web1. The second argument is the destination URI, which specifies the connection to the remote host and the hypervisor to use2. In this case, the destination URI is qemu+ssh://host2/system, which means to use the QEMU driver and connect to host2 via SSH, and use the system instance of libvirtd3. The other options are incorrect because they either use invalid commands or arguments, such as node-update, pool-add, patch, or cp, or they do not specify the destination URI correctly. References:

The command lxc-checkpoint is used to checkpoint and restore containers. Checkpointing a container means saving the state of the container, including its memory, processes, file descriptors, and network connections, to a file or a directory. Restoring a container means resuming the container from the saved state, as if it was never stopped. Checkpointing and restoring containers can be useful for various purposes, such as live migration, backup, debugging, or snapshotting. The command lxc-checkpoint has the following syntax:

lxc-checkpoint {-n name} {-D path} [-r] [-s] [-v] [-d] [-F]

The options are:

• -n name: Specify the name of the container to checkpoint or restore.
• -D path: Specify the path to the file or directory where the checkpoint data is dumped or restored.
• -r, --restore: Restore the checkpoint for the container, instead of dumping it. This option is incompatible with -s.
• -s, --stop: Optionally stop the container after dumping. This option is incompatible with -r.
• -v, --verbose: Enable verbose criu logging. Only available when providing -r.
• -d, --daemon: Restore the container in the background (this is the default). Only available when providing -r.
• -F, --foreground: Restore the container in the foreground. Only available when providing -r.

The command lxc-checkpoint uses the CRIU (Checkpoint/Restore In Userspace) tool to perform the checkpoint and restore operations. CRIU is a software that can freeze a running application (or part of it) and checkpoint it to a hard drive as a collection of files. It can then use the files to restore and run the application from the point it was frozen at1.

The other statements about the command lxc-checkpoint are not correct. It does not create a clone or an image of a container, nor does it double the memory consumptionof the container. It can work on both running and stopped containers, depending on the options provided. References:

• Linux Containers - LXC - Manpages - lxc-checkpoint.12
• lxc-checkpoint(1) - Linux manual page - man7.org3
• CRIU4

 LXD supports the following network interface types for containers: macvlan, bridged, physical, sriov, and ovn1. Macvlan creates a virtual interface on the host that is connected to the same network as the parent interface2. Bridged connects the container to a network bridge that acts as a virtual switch3. Physical attaches the container to a physical network interface on the host2. Ipsec and wifi are not valid network interface types for LXD containers. References:

• 1: Bridge network - Canonical LXD documentation
• 2: How to create a network - Canonical LXD documentation
• 4: LXD containers and networking with static IP - Super User