305-300 Full Virtualization — 15 Questions

Question 1

You are configuring a libvirt bridge network. Which file should you edit on a Debian/Ubuntu system to create a bridge interface 'br0' that includes 'eth0'?

Accepted Answer

/etc/network/interfaces. /etc/network/interfaces is the standard location for configuring network bridges on Debian-based systems.

Answer

/etc/sysconfig/network-scripts/ifcfg-br0

Answer

/etc/libvirt/qemu/networks/br0.xml

Question 2

Which command do you use to view the console output of a running guest VM?

Accepted Answer

virt-viewer vm_name. virsh console allows you to connect to the serial console of a guest.

Answer

virsh show-console vm_name

Answer

virsh view vm_name

Question 3

You are migrating a disk-based VM. You need to ensure the destination host can access the disk image. What must you configure?

Accepted Answer

A shared storage pool accessible by both hosts. Both the source and destination must have access to the same storage path or a shared storage pool.

Answer

A static IP for the VM

Answer

A local disk file on the destination

Question 4

How do you configure a VM to automatically start when the host boots?

Accepted Answer

virsh autostart vm_name. virsh autostart vm_name ensures the VM starts with the host.

Answer

virsh set-boot-auto vm_name

Answer

virsh config-start vm_name

Question 5

Which THREE of the following are valid Libvirt storage pool types?

Accepted Answer

iscsi. Libvirt supports various backends for storage including directories, LVM volume groups, and iSCSI targets.

Answer

ram

Answer

usb

Question 6

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 7

You need to migrate a running QEMU VM to a remote host using live migration. Which command-line argument for QEMU-KVM initiates a migration to a target host at 192.168.1.50 on port 4444?

Accepted Answer

-migrate tcp:192.168.1.50:4444. The -migrate command or the migrate QMP command is used, but for the CLI argument, the migration URI must be defined.

Answer

-remote 192.168.1.50:4444

Answer

-live-migrate 192.168.1.50:4444

Answer

-incoming tcp:192.168.1.50:4444

Question 8

When migrating a Libvirt domain using 'virsh migrate --live', which option must be specified to ensure the guest's memory state is copied over the network?

Accepted Answer

--copy-storage-all. The --live option manages the memory transfer, but the --copy-storage-all or --block-incremental option is required if the disks are not on shared storage.

Answer

--shared-storage

Answer

--migrate-disk

Answer

--memory-copy

Question 9

You are troubleshooting a libvirt network issue where the virtual machines cannot reach the external gateway. The virtual network uses a NAT configuration. Which file would you inspect to verify the iptables rules generated by libvirt for this network?

Accepted Answer

/etc/libvirt/qemu/networks/default.xml. Libvirt manages iptables rules dynamically, but the configuration is stored in the libvirt network XML files in /etc/libvirt/qemu/networks/ and the resulting rules appear in the NAT table.

Answer

/var/lib/libvirt/network/default.xml

Answer

/etc/sysconfig/network-scripts/ifcfg-virbr0

Answer

/etc/iptables/rules.v4

Question 10

You are configuring a Xen guest that requires direct hardware access to a specific network interface card. Which configuration parameter in the guest domain configuration file must be specified to enable PCI passthrough?

Accepted Answer

pci = [ '00:1f.1' ]. The pci option in the Xen domain configuration file allows passing through physical PCI devices to the guest domain.

Answer

device_pass = 'eth0'

Answer

hw_access = '00:1f.1'

Answer

vif = [ 'type=pci, bus=00:1f.1' ]

Question 11

You are configuring a QEMU-KVM guest to use VirtIO-net. Which parameter in the QEMU command line correctly enables the virtio-net-pci device with a tap interface named tap0?

Accepted Answer

-netdev tap,id=net0,ifname=tap0 -device virtio-net-pci,netdev=net0. The -netdev tap,id=net0,ifname=tap0 argument defines the backend, and -device virtio-net-pci,netdev=net0 defines the frontend.

Answer

-device virtio-net,backend=tap0

Answer

-netdev tap,id=tap0 -device virtio-net-pci,id=tap0

Answer

-net tap,ifname=tap0,model=virtio

Question 12

When managing storage pools using virsh, which command would you use to list all defined storage pools, including those that are inactive?

Accepted Answer

virsh pool-list --all. virsh pool-list --all displays all pools regardless of their current status.

Answer

virsh list-pools --inactive

Answer

virsh pool-info --all

Answer

virsh pool-show --all

Question 13

Which hypervisor type is considered 'Type 1' virtualization?

Accepted Answer

Xen. Type 1 hypervisors (bare metal) run directly on the hardware, such as Xen.

Answer

VMware Workstation

Answer

VirtualBox

Answer

QEMU (user mode)

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

You need to create a snapshot of a QCOW2 disk image without stopping the virtual machine. Which qemu-img sub-command should be used?

Accepted Answer

virsh snapshot-create-as --domain vm_name --name snap1 --disk-only. qemu-img snapshot -c creates a snapshot, but it should only be done on offline images. For live snapshots, virsh snapshot-create is required.

Answer

qemu-img create -f qcow2 -b image.qcow2 snapshot.qcow2

Answer

qemu-img snapshot -c snapshot_name image.qcow2

Answer

virsh checkpoint-create vm_name