305-300 Practice Test 1 — 10 Questions

Question 1

Which command is used to remove an unused Docker image?

Accepted Answer

docker rmi. 'docker rmi' is the command to remove an image.

Answer

docker rm

Answer

docker image delete

Answer

docker prune image

Question 2

You are using Docker and want to create a volume that is shared between multiple containers and persists even if the containers are deleted. What is the best approach?

Accepted Answer

Named volume. Named volumes are specifically designed for persistence and sharing independent of container lifecycles.

Answer

Anonymous volume

Answer

Tmpfs

Answer

Bind mount

Question 3

You are using BSD Jails and need to start a jail. Which utility is the standard management tool for jail administration?

Accepted Answer

jail. jail is the command to create or start a jail, and jailctl is also sometimes used in managed environments, but jexec is used for executing commands inside.

Answer

jexec

Answer

jails-admin

Answer

jail-manage

Answer

jls

Question 4

Which Dockerfile instruction is used to copy a file from the host file system into the image?

Accepted Answer

COPY. The COPY instruction is the standard way to move files from the build context into the image.

Answer

RUN

Answer

ADD

Answer

PUSH

Answer

IMPORT

Question 5

Which TWO of the following commands can be used to manage virtual networks in libvirt?

Accepted Answer

virsh net-define. virsh net-list and virsh net-define are standard commands.

Answer

virsh net-config

Answer

virsh net-start-all

Answer

virsh net-status

Question 6

Which THREE of the following attributes can be defined within the <memoryBacking> XML block?

Accepted Answer

<hugepages/>. hugepages, locked, and source (type) are all valid components of memory backing.

Answer

<swap-limit/>

Answer

<balloon-rate/>

Question 7

Which command lists all Docker images currently on the host?

Accepted Answer

docker images. 'docker images' or 'docker image ls' lists images.

Answer

docker ps

Answer

docker show

Answer

docker list

Question 8

Which THREE networking modes are natively supported by Docker?

Accepted Answer

bridge. Bridge, host, and none are standard Docker network drivers.

Answer

gateway

Answer

tunnel

Question 9

You are using systemd-nspawn and want to run a container that shares the host's network namespace. Which flag is required?

Accepted Answer

--network-host. The --private-network flag disables the network, while omitting it or specifically using --network-veth allows various configurations; however, to share the host's namespace, one must use --network-host.

Answer

--private-network=false

Answer

--network-veth

Answer

--share-net

Question 10

You are configuring an LXC container and need to grant it access to a specific host character device without running the container in privileged mode. Which configuration option in the container's config file should you use?

Accepted Answer

lxc.cgroup2.devices.allow. The lxc.cgroup2.devices.allow directive is the standard way to whitelist specific hardware devices for a container in cgroup2-based environments.

Answer

lxc.cap.keep

Answer

lxc.mount.entry

Answer

lxc.hook.pre-start