scenario questions

Which command checks the status of the libvirtd service?

A KVM guest is configured with a virtio-blk disk and a virtio-net device. Under heavy network load the guest CPU shows high system time inside the guest, and the host shows high context-switch rates for the QEMU process. The administrator wants to reduce per-packet I/O overhead without changing the guest OS drivers. Which change is most appropriate?

A Packer build targeting the qemu builder completes, but the resulting image boots to a login prompt and never runs your provisioning scripts. You configured an ssh communicator with a username and password. Which condition most likely prevents Packer from connecting to the guest during the build?

A libvirt storage pool of type 'dir' contains several qcow2 images. You want to create a new snapshot of an existing VM using virsh. Which command sequence is required to create an internal snapshot of the VM's current state?

A system administrator is troubleshooting a container that cannot resolve DNS names for other containers on the same user-defined Docker bridge network. The container's /etc/resolv.conf points to 127.0.0.11. Which Docker feature is responsible for providing this DNS resolution?

Which hypervisor is known for being 'Type 2'?

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

In a FreeBSD Jail, how can you ensure the jail starts automatically at boot?

Which TWO of the following are common ways to connect to a virtual machine's console?

A Docker host runs a container with the default bridge network. The container needs to resolve external DNS names, but `docker exec mycontainer ping example.com` fails with 'unknown host'. The host itself resolves names correctly. Which Docker daemon configuration should you check first?

Which Docker network driver should you use if you want containers to have their own IP addresses on the physical network, as if they were physically connected to the network?

You need to change the MAC address of a network interface for a virtual machine. Where is this configured?

What is the purpose of the 'virt-install' tool?

You are configuring a virtual network with a static IP address for a VM. Where do you define the DHCP host entry in the libvirt network XML?

You are configuring a KVM guest to use a paravirtualized clock and to report its IP addresses to the host so that libvirt can display them with virsh domifaddr. (Choose two.)

When building a Dockerfile, which instruction should be used to define the user context for subsequent RUN, CMD, and ENTRYPOINT instructions?

When configuring a systemd-nspawn container, what is the effect of the --private-network option?

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?

Which libvirt network type uses a bridge on the host to connect virtual machines directly to the physical network?

Which TWO of the following are valid storage pool types in libvirt?

You are running a Docker container and need to map port 8080 on the host to port 80 in the container. Which command argument should you use?

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

You are using Vagrant to manage a development environment. You need to run a shell script that installs dependencies after the VM boots for the first time. Which provisioner type should you use in your Vagrantfile?

You have a qcow2 disk image that is growing too large. You want to shrink the file size on the host while keeping the virtual disk the same size. Which steps must you perform first?

Which THREE instructions in a Dockerfile can modify the image's filesystem?

What is the primary function of the libvirtd daemon?

A KVM host runs a Windows guest whose virtual disk is backed by a raw image file on an NFS mount. After a host reboot, the guest fails to start with 'Permission denied' on the disk path, although the file exists and is readable by root. The host uses SELinux enforcing mode. Which action resolves the problem?

You are configuring a KVM host that will run several guests. You want each guest to be able to communicate with other guests and the host on the same subnet, while still allowing external hosts to reach the guests directly. You decide to use a libvirt virtual network with a bridge. Which libvirt network configuration element must be present to enable direct Layer 2 connectivity between the guests and the physical LAN?

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

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?

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?

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

You are using systemd-nspawn to run a container and need to allow it to use the host's network stack directly, without any network namespace isolation. Which option should you pass to systemd-nspawn?

In a Vagrant environment, where should sensitive data like API keys be stored to avoid committing them to version control?

Which TWO of the following commands can be used to monitor VM resource utilization?

You are configuring LXC and want to set a CPU limit for a container. Which cgroup parameter is used to specify the quota of CPU time in microseconds?

You are reviewing a KVM host and need to identify which of the following CPU features must be exposed to a guest to allow hardware-assisted nested virtualization inside that guest. (Choose two.)

When configuring a VM in libvirt, you want to ensure the highest performance for disk I/O. Which driver type should you select for the disk device?

Which THREE networking modes are natively supported by Docker?

You are provisioning a KVM guest with virt-install. The guest must use a pre-existing disk image located at /var/lib/libvirt/images/web.img and must not have the image created or modified by virt-install. Which option should you include in the virt-install command?

You are using systemd-nspawn to run a container and want to ensure that the container's processes are isolated from the host's process tree. Which option should you use?

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

Which THREE settings are commonly configured in the 'provider' block of a Vagrantfile for virtualbox?

You are using QEMU/KVM with libvirt on a host and want to gracefully shut down a running domain named 'db01' so the guest OS performs its normal shutdown sequence. Which virsh command should you use?

A KVM host uses a bridged network 'br0' with the physical NIC enslaved. You want a guest to obtain an IP address from the same DHCP server as the host's physical LAN, without NAT. Which libvirt network interface definition in the domain XML achieves this?

When using Vagrant to manage a libvirt-based provider, which command verifies that the virtual machine is currently running and identifies the provider in use?

Which THREE of the following are valid components of a libvirt domain XML configuration?

What does the 'docker rm' command do?

Which hypervisor type is considered 'Type 1' virtualization?

A Docker container is failing to connect to an external database despite the host being able to ping it. You suspect a bridge networking issue. Which command allows you to inspect the current NAT rules created by Docker?

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?

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

You are using systemd-nspawn. How do you create an image of a container to be used as a template?

What is the purpose of the virtio-balloon driver in a guest?

You need to ensure that a specific package is installed during the first boot of a cloud instance. Which cloud-init key should be added to the configuration?

Which command is used to display the configuration of a Packer build in a readable format?

What is the primary function of a Docker Registry?

You are configuring a rootless Podman container that must persist data across container restarts and also needs to communicate with other containers on the same host using a user-defined network. Which two actions must you perform to achieve these goals? (Choose two.)

You are troubleshooting a Docker container that fails to start with the error message: 'Error response from daemon: failed to create task for container: failed to create shim task: OCI runtime create failed: runc create failed: unable to start container process: error during container init: error mounting /proc: no such file or directory'. The host is running a recent Linux kernel and Docker is using the default runtime. What is the most likely cause?

What is the purpose of 'virt-top'?

When defining a Vagrant network configuration for a libvirt provider, which mode allows the VM to receive an IP address directly from the physical network's DHCP server?

A guest was created with a 20 GB qcow2 disk and has been running for months. The administrator wants to give the guest additional space without recreating the disk, and the guest uses a single ext4 partition with no LVM. Which approach is valid with virsh and standard tools?

Which file in a Vagrant project directory is processed by default to define the virtual environment configuration?

You are configuring a virtual network in libvirt that allows VMs to communicate with each other and the host, but prevents them from accessing the external network. Which mode should you select for this network?

You are using QEMU to emulate an ARM architecture on an x86_64 host. You need to ensure the guest has access to the host's filesystem directly without configuring network shares. Which option is the correct way to pass a directory through to the guest?

You are configuring an LXC container and need to limit its CPU and memory usage. Which TWO of the following configuration options in the container's config file are valid for this purpose? (Choose two.)

When using 'docker-compose', which file format is used to define the services?

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?

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?

What is the purpose of the 'virsh' tool?

Which THREE configuration items can be managed via cloud-init 'write_files' module?

In a Vagrantfile, which method is used to pass environment variables into the guest virtual machine during the provisioning phase?

A KVM host runs libvirt with a default storage pool at /var/lib/libvirt/images. You need to create a new qcow2-backed volume named 'app-disk.qcow2' with a virtual size of 40 GB inside the pool named 'default'. Which single virsh command accomplishes this?

You are troubleshooting a container networking issue. You notice that traffic from the container is not being SNATed. What should you check in the iptables rules?

Which command is used to remove an unused Docker image?

Which TWO of the following are valid container orchestration platforms?

You are using cloud-init to configure a VM that must run a script only on the very first boot, and the script must not run again on subsequent reboots. The script is provided as a MIME part in a multipart user-data file. Which cloud-init module should be used to ensure this behavior?

Which TWO commands are used to manage images in Docker?

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

Which THREE storage drivers are supported by Docker?

What is the main advantage of using a container over a virtual machine?

You need to inspect the metadata of a specific Docker image without pulling it from a remote registry. Which command should you use?

You are debugging a Docker image buildup that fails at the 'RUN' instruction due to missing network access during the build. What command option should be checked if the build environment uses a proxy?

You are troubleshooting a libvirt migration that fails with 'Operation not supported: Migration requires a storage pool'. You need to perform a block migration where the storage is copied to the destination host. Which command-line flag enables this functionality?

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

Which QEMU-KVM feature allows you to save the state of a VM to a file and resume it later?

A junior administrator needs to start the libvirt-managed guest 'db01' and confirm that it is running. Which pair of commands accomplishes this?

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

A production KVM guest uses a virtio-blk disk and experiences periodic I/O stalls during heavy write bursts. You want to switch the guest disk to virtio-scsi with multiple queues to improve parallelism without reinstalling the guest OS. Which change should you make to the domain XML?

In the context of virtualization, what does 'ballooning' refer to?

An administrator is configuring a KVM host that will run a latency-sensitive guest. The goal is to reduce scheduling jitter and improve cache locality for that guest's vCPUs. Which TWO measures are appropriate? (Choose two.)

You need to convert a raw disk image to QCOW2 format to enable snapshotting. Which command is correct?

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

Which THREE items are typically included in an OpenVZ configuration file?

You are troubleshooting a Docker container that fails to start with the error 'no space left on device' even though `df -h` shows ample free space on the host's root filesystem. The Docker data root is on a separate partition. Which command should you use to check the actual disk usage of Docker's data root?

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

You need to enable hugepages for a VM in libvirt to improve memory performance. What XML entry do you add?

What is the default behavior of Vagrant when a box is not found locally on the host machine?

Which tool is commonly used alongside Packer to validate the configuration file for syntax errors before attempting a build?

An administrator needs to run a container that requires access to a specific block device on the host, such as /dev/sdb, for direct I/O operations. Which Docker run option should be used to grant the container access to this device?

You are managing a KVM host and need to create a new storage pool that uses a directory on the host filesystem to store disk images. After creating the directory /var/lib/libvirt/images/extra, you want to define and start a libvirt storage pool named 'extra-pool' that uses this directory. Which sequence of virsh commands accomplishes this?

In cloud-init, which syntax is required at the very beginning of the configuration file to ensure it is recognized as a cloud-config script?

In a Docker swarm, which mode of service publishing allows incoming traffic to be load-balanced across all healthy container replicas?

Which command lists all Docker images currently on the host?

You are building a Vagrant environment for a development team. The Vagrantfile must provision three identical web servers and one load balancer, all using the same base box but with different hostnames and static IP addresses. Which Vagrantfile construct should you use to define these machines and their individual settings?

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

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

What does the term 'KVM' stand for?

Which utility is best for creating a new libvirt storage pool?

Which Docker command is used to display the resource usage (CPU, memory) of running containers?

Which cloud-init module is responsible for setting the hostname of the instance during the initial boot process?

You need to create a new storage pool for KVM guests using the virsh command-line tool. The pool should use a directory on the host filesystem at /var/lib/libvirt/images/extra. Which command correctly defines and starts this pool?

You maintain a Vagrant environment where a single Vagrantfile defines three web servers and one database server. You need each web server to use a different forwarded SSH port on the host because port 2222 is already taken by another project. Which approach correctly assigns unique host ports per machine?

You are troubleshooting a KVM guest that fails to boot after you changed its XML configuration. You want to verify and correct the guest's definition without starting it. Which TWO of the following actions are appropriate? (Choose two.)

A Packer template targets the qemu builder to produce a KVM-compatible image. The build completes without error, but when the resulting qcow2 file is booted with `qemu-system-x86_64 -drive file=image.qcow2,if=virtio`, the guest kernel panics with "VFS: Unable to mount root fs" because it cannot see any block device. The template defines only `iso_url`, `iso_checksum`, `ssh_username`, and `ssh_password`. Which change to the template is MOST likely to resolve this?

Which THREE configuration items can be managed by LXC cgroups?

You are building a Docker image and want to ensure that a build-time variable is available only during the build, not persisted in the final image's environment. Which instruction should you use?

What is the default location for libvirt domain configuration XML files?

Which TWO components are defined in a Packer 'build' block?

You are optimizing a Dockerfile to reduce image size. Which THREE of the following practices are recommended?

A developer wants to run a short-lived container that executes a command and then removes itself automatically after exit. Which `docker run` flag should be used?

Which file system structure is typically used for QEMU virtual disk images when using LVM?

You are troubleshooting a performance issue and want to pin a VM process to specific physical CPU cores. Which XML element is used?

Which command is used to list all active running domains?

You are migrating a running KVM guest from hostA to hostB with virsh migrate --live. The migration fails immediately with 'error: internal error: Attempt to migrate guest to the same host'. Both hosts share the same NFS storage and have identical CPU models. Which condition most likely explains this failure?

In the context of container orchestration, what is the role of a 'sidecar' container?

When using Packer with the QEMU builder, what does the 'format' option in the 'qemu' builder define?

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

You are debugging a Docker network issue where containers on different hosts cannot communicate. Which network driver is specifically designed to support multi-host overlay networking?

You want to optimize disk I/O performance for a KVM guest. Which bus type should you configure in the libvirt domain XML for the virtual disk?

You are preparing a KVM guest for a maintenance window and need to shut it down gracefully so the guest OS can flush buffers and stop services. Which virsh command should you use?

Which command-line tool is primarily used to inspect the metadata and configuration of a running Docker container?

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

Which THREE of the following are components of the Docker architecture?

You need to enable and configure a UEFI firmware boot for a new KVM guest on a libvirt host. Which TWO of the following steps are required? (Choose two.)

You are using QEMU to emulate an ARM architecture on an x86 host. Which binary would you typically use to execute this?

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

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

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

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

You are building a Docker image and need to ensure that the container process runs as a non-root user with UID 1000 and that this user exists in the image. Which pair of Dockerfile instructions achieves this correctly?

You administer a KVM host running libvirt. A developer needs a guest to be able to communicate with the host directly over a private network without any NAT or bridging to the physical LAN. You decide to use libvirt's default virtual network. Which virsh command will display the XML definition of this default network so you can inspect its forwarding mode and DHCP range?

You are configuring cloud-init to inject an SSH key into a new VM. Which directive in the configuration metadata ensures the key is added to the correct user's authorized_keys file?

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

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

What is a 'snapshot' in virtualization?

You are building a multi-stage Dockerfile and want to copy a binary from the 'builder' stage to the final stage. Which syntax is correct?

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?

Which component is responsible for the actual hardware-assisted virtualization in KVM?

Which THREE of the following are valid elements inside the <interface type='bridge'> block?

Which command-line option is used to run a Docker container in the background (detached mode)?

You are managing an LXC container and need to create a snapshot of the container's root file system. Which command achieves this?

In an OpenVZ environment, you need to limit the number of processes a container can create. Which parameter in the container configuration file should be modified?

Which of these is a valid virtualization storage pool type supported by libvirt?

In systemd-nspawn, how do you specify a different root directory for the container?

What is the primary difference between a container image and a container instance?

You are managing a KVM host and need to gracefully shut down a running guest named 'dbserver'. Which virsh command should you use?

What is the primary function of the ENTRYPOINT instruction in a Dockerfile?

Which THREE of the following are necessary components for a successful KVM virtualization environment on Linux?

You are using Packer to build a KVM-compatible QEMU image for an on-premises OpenStack cloud. The build completes successfully, but the resulting image fails to boot because the virtual disk is not recognized. You verify that the QEMU builder is configured with accelerator 'kvm' and the correct machine type. Which QEMU builder option should you review to ensure the disk image is created in a format that OpenStack can use?

How do you view the logs of a running container?

Which instruction in a Dockerfile is best suited for installing packages to minimize image size?

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

How do you define a new libvirt virtual network from an XML file named 'net.xml'?

You are troubleshooting a KVM guest that fails to start with the error 'unsupported configuration: CPU mode 'host-passthrough' requires KVM'. Which of the following is the most likely cause?

In a Packer build process for OpenStack, which 'post-processor' type is typically used to upload the resulting image to the Glance image service?

Which THREE of the following XML elements are used to define a virtual disk in a domain?

Which TWO commands are valid for inspecting container network settings?

What is the purpose of the 'rkt' (Rocket) container runtime?

Which THREE of the following steps are involved in performing a manual disk migration of a VM?

You are using Docker and need to inspect the metadata of a running container, including its IP address, environment variables, and mounted volumes. Which command provides all this information in a single JSON output?

Which command shows the history of layers in a Docker image?

Which command is used to display the XML configuration of a running VM domain named 'webserver'?

You are running a Docker container that needs to persist data in a directory that is backed by a storage area on the host. The host uses the overlay2 storage driver. You want the container to write data that survives container removal and is accessible directly on the host filesystem. Which approach should you use?

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?

A developer is building a container image and wants to reduce its final size by ensuring that no package manager cache files remain in the image layers. Which Dockerfile instruction should be used to remove these temporary files during the build?

You are setting up a KVM guest that requires very low latency for a real-time workload. You want to dedicate a physical CPU core to the guest and prevent the host from scheduling other tasks on that core. Which libvirt domain XML configuration achieves this?

You are using Docker and need to view the layers that make up an image to understand its build history. Which command should you use?

A cloud-init configuration file is failing to apply the 'write_files' module. Which log file on the target instance should you examine to diagnose the parsing error?

What is the role of the 'Dockerfile' in the container build process?

A VM is hanging because of a specific hardware emulation bug in QEMU. You need to enable the 'qxl' video device to see if it resolves display issues. What is the XML tag to define the video device in the domain config?

You are creating a Vagrant environment for a development team. The team needs a single VM that uses the 'ubuntu/jammy64' box and forwards host port 8080 to guest port 80. Which Vagrantfile configuration block correctly defines this?

Which TWO of the following are benefits of using the QCOW2 image format?

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

You are running a Podman container as a non-root user with rootless mode. The container needs to bind to TCP port 80 inside the container's network namespace so a legacy application can listen for HTTP traffic. Which capability must be added to the container to allow binding to this privileged port without running the container as root?

Which TWO of the following commands are used for VM disk image management?

What is the primary function of the cloud-init 'runcmd' module?

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?

Which command provides system-wide information about the Docker installation?

Which THREE of the following are common cloud-init modules?

Which THREE directives are valid under the cloud-init 'users' configuration section?

You need to run a container that requires access to the host's network namespace directly to perform packet capture. Which Docker run flag should you use?

You have an active domain named 'myvm'. How do you gracefully shut it down?

Which flag is used to run a container in the background?

What does 'QEMU' stand for?

What is the purpose of the 'ENTRYPOINT' instruction in a Dockerfile?

Which TWO of the following are key features of the QEMU-KVM hypervisor?

How can you force a refresh of a libvirt storage pool named 'isos'?

You are configuring an OpenVZ container. Which command is used to set the hostname of the container from the host?

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

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?

You are using Packer to build an image for a private cloud. The build uses the 'qemu' builder and a 'shell' provisioner. The provisioner script runs but fails to install a package because the package repository is unreachable. You suspect the VM has no network connectivity during provisioning. Which Packer feature should you verify to ensure the VM has network access?

Which TWO of the following are true regarding container orchestration platforms?

Which TWO of the following are valid libvirt storage pool lifecycle commands?

You are managing a Xen host and need to live-migrate a domain between two physical servers. The migration fails with a domain lock error. Which command is the standard way to initiate a live migration while ensuring the target host is prepared to receive the domain?

You are building a Docker image for a Python web application. The Dockerfile currently contains: FROM python:3.9-slim COPY . /app WORKDIR /app RUN pip install -r requirements.txt CMD ["python", "app.py"] After building, you notice that every time you change app.py, the entire pip install step re-runs, making builds slow. Which change to the Dockerfile will best address this?

Which command is used to stop all running containers?

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

Which Packer builder is most appropriate for creating an image specifically for Amazon Web Services (AWS)?

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?