305-300 Practice Test 3 — 30 Questions

Question 1

Which TWO of the following are true regarding the differences between rkt (Rocket) and Docker?

Accepted Answer

rkt utilized a daemonless architecture. rkt focused on pods and a daemonless architecture, whereas Docker initially used a centralized daemon.

Answer

rkt only supported binary images

Answer

Docker is a sub-project of rkt

Answer

Docker never had a daemon

Question 2

Which command is used to list all active running domains?

Accepted Answer

virsh list. virsh list lists active domains by default.

Answer

virsh domlist

Answer

virsh status

Answer

virsh list --all

Question 3

Which TWO of the following are valid ways to configure VM networking?

Accepted Answer

NAT. Bridging and NAT are both native libvirt network configuration methods.

Answer

Hub-based switching

Answer

VLAN tagging on bridge

Answer

Direct routing

Question 4

Which THREE configuration items can be managed by LXC cgroups?

Accepted Answer

CPU shares. Cgroups manage memory, CPU, and device access.

Answer

User permissions

Answer

DNS settings

Question 5

A Docker container running a web server is unable to serve traffic on port 8080. You verify the Dockerfile exposes port 80. What is the correct way to map this for external access?

Accepted Answer

docker run -p 8080:80. The -p flag in docker run is used to map host ports to container ports.

Answer

docker run -p 80:8080

Answer

docker run --net host

Answer

docker run --expose 8080

Answer

docker run -P 8080

Question 6

Which TWO pieces of information does Packer require to build an image for an existing cloud environment?

Accepted Answer

API credentials. Packer needs credentials (like API keys) and region/availability zone information to interact with cloud APIs.

Answer

Local disk path

Answer

BIOS password

Answer

Host OS version

Question 7

Which file system format is specifically designed for QEMU/KVM to support advanced features like copy-on-write, snapshots, and compression?

Accepted Answer

qcow2. QCOW2 (QEMU Copy-On-Write version 2) is the standard format for KVM that supports these features.

Answer

vmdk

Answer

vhdx

Answer

raw

Question 8

Which THREE of the following are required for a successful live migration between two KVM hosts using libvirt?

Accepted Answer

Shared storage. Shared storage, SSH access, and matching CPU models are critical requirements for a smooth live migration.

Answer

Identical network card models

Answer

Matching guest kernel versions

Question 9

You are migrating a legacy application to an LXC container and need to ensure the container has access to the host's /dev/sda block device. Which configuration key must be added to the container's configuration file?

Accepted Answer

lxc.cgroup.devices.allow = b 8:0 rwm. To allow a container to access host devices, the lxc.cgroup.devices.allow and lxc.mount.entry must be configured properly in the container config.

Answer

lxc.mount.device = /dev/sda

Answer

lxc.cap.sys_admin = 1

Answer

lxc.dev.access = /dev/sda

Question 10

Which TWO of the following are valid storage drivers used by Docker to manage image layers?

Accepted Answer

overlay2. Overlay2 and aufs are both well-known storage drivers for Docker.

Answer

ext4

Answer

vfs-driver

Answer

zfs-layer

Question 11

You need to attach a new block device to a running VM. What virsh command achieves this?

Accepted Answer

virsh attach-disk vm_name /path/to/img vda. virsh attach-disk is the correct command to hot-plug a disk.

Answer

virsh attach-device-file vm_name /path/to/img

Answer

virsh add-device vm_name /path/to/img

Answer

virsh hotplug-disk vm_name /path/to/img

Question 12

You need to add a second NIC to a VM via XML. How do you ensure the second NIC uses a different MAC address than the first one?

Accepted Answer

Add a second block with a unique . You define a new block with a unique .

Answer

You cannot have two NICs in one VM

Answer

Libvirt assigns the same MAC automatically

Answer

Use the same but different

Question 13

Which THREE of the following are legitimate security concerns when managing a virtualization host?

Accepted Answer

Unencrypted VNC connections. Insecure VNC access, unauthorized host access, and guest-to-host escapes are all major concerns.

Answer

Network interface speed

Answer

Hard drive fragmentation

Question 14

Which file is primarily responsible for defining the configuration and environment variables for an OpenVZ container?

Accepted Answer

/etc/vz/conf/CTID.conf. In OpenVZ, containers are managed via configuration files located in /etc/vz/conf/.

Answer

/etc/openvz/config

Answer

/var/lib/vz/config

Answer

/etc/vz/container.conf

Answer

/etc/vz/vz.conf

Question 15

In a Xen environment, which command would you use to change the number of VCPUs allocated to a running domain 'dom1' to 4?

Accepted Answer

xl vcpu-set dom1 4. xl vcpu-set is the standard command in modern Xen (xl toolstack) to adjust vCPUs.

Answer

virsh setvcpus dom1 4

Answer

xl mem-set dom1 4

Answer

xm set-vcpu dom1 4

Question 16

You want to limit the bandwidth of a virtual network interface. Which XML element within <interface> allows you to configure this?

Accepted Answer

. The element allows setting inbound and outbound throughput limits.

Answer

<limit-rate>1000</limit-rate>

Answer

<network-speed>1000</network-speed>

Answer

<traffic-control>1000</traffic-control>

Question 17

Which command is used to start a VM that has been defined?

Accepted Answer

virsh start vm_name. virsh start vm_name boots the virtual machine.

Answer

virsh launch vm_name

Answer

virsh boot vm_name

Answer

virsh run vm_name

Question 18

When cleaning up Docker resources, which command will remove all stopped containers, unused networks, and dangling images in one step?

Accepted Answer

docker system prune. docker system prune removes all unused data, which is the most efficient cleanup method.

Answer

docker container prune

Answer

docker volume prune

Answer

docker image prune -a

Answer

docker cleanup

Question 19

Which TWO types of namespaces are commonly used to achieve container isolation in Linux?

Accepted Answer

Network. Network and PID namespaces are fundamental for containerization.

Answer

GPU

Answer

CPU

Answer

Kernel

Question 20

Which TWO of the following are valid ways to trigger provisioning in Vagrant?

Accepted Answer

vagrant provision. 'vagrant up --provision' runs provisioners during startup, and 'vagrant provision' runs them on a running machine.

Answer

vagrant start

Answer

vagrant reload --provision

Answer

vagrant apply