305-300 Practice Test 15 — 15 Questions

Question 1

Which THREE of the following are necessary to enable QEMU guest agent integration?

Accepted Answer

Installing qemu-guest-agent inside the guest. Installing the guest agent, adding the channel to the XML, and restarting the VM are the required steps.

Answer

Adding a network bridge

Answer

Enabling VNC password

Question 2

In a Docker environment, you are observing that container logs are consuming too much disk space. Which logging driver should you configure to limit the number and size of log files?

Accepted Answer

json-file. The 'json-file' logging driver supports 'max-size' and 'max-file' options to rotate and cap logs.

Answer

none

Answer

syslog

Answer

journald

Question 3

When provisioning with Vagrant, which command is best used to apply changes to a configuration (like adding a new shell script) without destroying the existing virtual machine?

Accepted Answer

vagrant provision. 'vagrant provision' triggers the configured provisioners (shell, ansible, etc.) on a running VM without destroying it.

Answer

vagrant halt

Answer

vagrant reload

Answer

vagrant up

Question 4

Which THREE features are provided by Linux Namespaces in the context of containers?

Accepted Answer

PID isolation. Namespaces provide isolation for Process IDs, Networking, and Mount points.

Answer

CPU scheduling

Answer

Disk quotas

Question 5

Which command is used to list all defined virtual networks in Libvirt?

Accepted Answer

virsh net-list --all. virsh net-list --all displays both active and inactive virtual networks.

Answer

brctl show

Answer

virsh domiflist

Answer

virsh list-networks

Question 6

You need to inspect the configuration of an LXC container named 'web'. Which command should you use?

Accepted Answer

lxc-info -n web. 'lxc-info -n web' displays information about the specified container.

Answer

lxc-check

Answer

lxc-ls

Answer

lxc-config

Question 7

When using Docker volumes, which type of mount should you use if you want the data to persist on the host filesystem at a specific, user-defined path?

Accepted Answer

Bind mount. Bind mounts allow mapping a specific host path to a container path, providing persistence at a known location.

Answer

Named volume

Answer

Anonymous volume

Answer

Tmpfs mount

Question 8

Which command allows you to enter an existing running container and execute a new command inside it?

Accepted Answer

docker exec. 'docker exec' is the standard command to run a new process in a running container.

Answer

docker commit

Answer

docker attach

Answer

docker run

Question 9

Which TWO methods can be used to pass configuration data to cloud-init during instance creation?

Accepted Answer

user-data. Cloud-init accepts configuration via 'user-data' (the primary config) and 'metadata' (key-value pairs, though less common for full configs).

Answer

kernel-args

Answer

bios-injection

Answer

sys-config

Question 10

When using Vagrant with multiple machines in a single Vagrantfile, how do you define individual configurations?

Accepted Answer

config.vm.define :name. You use the 'config.vm.define' block to distinguish between multiple machines within one configuration file.

Answer

config.vm.box_set

Answer

config.vm.instance

Answer

config.vm.multi

Question 11

You are using libvirt to manage a QEMU VM. You want to pass a specific host USB device with vendor ID 1234 and product ID 5678 to the guest. Which XML element is used inside the <devices> block to define this?

Accepted Answer

. The element with mode='subsystem' and type='usb' is used for USB passthrough.

Answer

Answer

Answer

<usb-passthrough vendor='1234' product='5678'/>

Question 12

You are troubleshooting a Docker container that cannot reach the internet despite the host having connectivity. The container uses the default bridge network. Which iptables chain is most likely causing the block?

Accepted Answer

FORWARD. Docker adds rules to the FORWARD chain in the filter table to manage traffic between the bridge network and external networks.

Answer

PREROUTING

Answer

POSTROUTING

Answer

OUTPUT

Question 13

You are configuring a virtual network with a bridge. You want to disable DNS services for that network. What XML element within the <network> definition do you remove or comment out?

Accepted Answer

. The block is responsible for the network's DNS service.

Answer

<disable-dns/>

Answer

Answer

Question 14

What is the primary function of the libvirtd daemon?

Accepted Answer

To act as a management API for virtualization technologies. libvirtd provides a management layer (API) to control various virtualization technologies like KVM, Xen, and LXC.

Answer

To manage kernel modules for KVM

Answer

To emulate physical hardware for the host

Answer

To provide a graphical interface for QEMU

Question 15

Which option for 'qemu-img create' allows you to create a preallocated image?

Accepted Answer

-o preallocation=full. -o preallocation=full creates a fully preallocated file.

Answer

--prealloc=true

Answer

-p full

Answer

-f preallocated