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

LXD supports the following network interface types in an LXD container configuration1:

• macvlan: Creates a virtual interface on the host with a unique MAC address and attaches it to an existing physical interface. This allows the container to have direct access to the physical network, but prevents communication with the host and other containers on the same host2.
• bridged: Connects the container to an existing bridge interface on the host. This allows the container to communicate with the host and other containers on the same bridge, as well as the external network if the bridge is connected to a physical interface3.
• physical: Passes an existing physical interface on the host to the container. This allows the container to have exclusive access to the physical network, but removes the interface from the host4.

The other network interface types, ipsec and wifi, are not valid in an LXD container configuration. Ipsec is a protocol for secure communication over IP networks, not a network interface type. Wifi is a wireless technology for connecting devices to a network, not a network interface type. References:

• About networking - Canonical LXD documentation
• Macvlan network - Canonical LXD documentation
• Bridge network - Canonical LXD documentation
• Physical network - Canonical LXD documentation

 A Pod in Kubernetes is a collection of one or more containers that share the same network and storage resources, and a specification for how to run the containers. A Pod is the smallest unit of workload Kubernetes can run, meaning that it cannot be divided into smaller units. Therefore, option C is correct. All containers of a Pod run on the same node, which is the smallest unit of computing hardware in Kubernetes. A node is a physical or virtual machine that hosts one or more Pods. Therefore, option A is also correct. Pods are not always created automatically and cannot be explicitly configured. Pods can be created manually using YAML or JSON files, or using commands like kubectl run or kubectl create. Pods can also be created automatically by higher-level controllers, such as Deployment, ReplicaSet, or StatefulSet. Therefore, option B is incorrect. When a Pod fails, Kubernetes does not restart the Pod on another node by default. Pods are ephemeral by nature, meaning that they can be terminated or deleted at any time. If a Pod is managed by a controller, the controller will create a new Pod to replace the failed one, but it may not be on the same node. Therefore, option D is incorrect. systemd is not used to manage individual Pods on the Kubernetes nodes. systemd is a system and service manager for Linux operating systems that can start and stop services, such as docker or kubelet. However, systemd does not interact with Podsdirectly. Pods are managed by the kubelet service, which is an agent that runs on each node and communicates with the Kubernetes control plane. Therefore, option E is incorrect. References:

• Pods | Kubernetes
• What is a Kubernetes pod? - Red Hat
• What’s the difference between a pod, a cluster, and a container?
• What are Kubernetes Pods? | VMware Glossary
• Kubernetes Node Vs. Pod Vs.Cluster: Key Differences - CloudZero

The command lxc-attach is used to execute a command in a running LXC container. It allows the user to start a process inside the container and attach to its standard input, output, and error streams1. For example, the command lxc-attach -n mycontainer -- ls -lh /home will list all the files and directories in the /home directory of the container named mycontainer1. The other options are not valid LXC commands. The command lxc-batch does not exist. The command lxc-run is an alias for lxc-start, which is used to start a container, not to execute a command in it2. The command lxc-enter is also an alias for lxc-attach, but it is deprecated and should not be used3. The command lxc-eval is also not a valid LXC command. References:

• 1: Executing a command inside a running LXC - Unix & Linux Stack Exchange.
• 2: lxc-start: start a container. - SysTutorials.
• 3: lxc-attach: start a process inside a running container. - SysTutorials.

The correct way to share data between several virtual machines running on the same Linux-based host system is by using a network file system or file transfer protocol. A network file system (NFS) is a distributed file system protocol that allows a user on a client computer to access files over a network in a manner similar to how local storage is accessed1. A file transfer protocol (FTP) is a standard network protocol used for the transfer of computer files between a client and server on a computer network2. Both methods allow data to be shared between virtual machines regardless of their underlying file systems or virtualization technologies. The other options are incorrect because they either do not work or are not feasible. Option A is wrong because each virtual machine has its own file system that is not directly accessible by other virtual machines. Option B is wrong because there is no such device as /dev/virt-disks/remote/ that can be used to mount other virtual machines’ file systems. Option C is wrong because a ramdisk is a volatile storage device that is not suitable for sharing data between virtual machines. Option E is wrong because attaching the same virtual hard disk to multiple virtual machines can cause data corruption and conflicts, and EXT4 does not have any sharing extensions that can prevent this. References:https://kb.vmware.com/s/article/1012706

https://bing.com/search?q=data+sharing+between+virtual+machines

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