The commandvirsh vol-list vmsreturns the following error: error: failed to get pool 'vms' error: Storage pool not found: no storage pool with matching name 'vms ' Given that the directory/vmsexists, which of the following commands resolves this issue?
Correct Answer: D
Explanation The command virsh pool-create-as vms dir --target /vms creates and starts a transient storage pool named vms of type dir with the target directory /vms12. This command resolves the issue of the storage pool not found error, as it makes the existing directory /vms visible to libvirt as a storage pool. The other commands are invalid because: * dd if=/dev/zero of=/vms bs=1 count=0 flags=name:vms is not a valid command syntax. The dd command does not take a flags argument, and the output file /vms should be a regular file, not a directory3. * libvirt-poolctl new --name=/vms --type=dir --path=/vms is not a valid command name. There is no such command as libvirt-poolctl in the libvirt package4. * qemu-img pool vms:/vms is not a valid command syntax. The qemu-img command does not have a pool subcommand, and the vms:/vms argument is not a valid image specification5. * touch /vms/.libvirtpool is not a valid command to create a storage pool. The touch command only creates an empty file, and the .libvirtpool file is not recognized by libvirt as a storage pool configuration file6. References: * 1: virsh - difference between pool-define-as and pool-create-as - Stack Overflow * 2: dd(1) - Linux manual page - man7.org * 3: 12.3.3. Creating a Directory-based Storage Pool with virsh - Red Hat Customer Portal * 4: libvirt - Linux Man Pages (3) * 5: qemu-img(1) - Linux manual page - man7.org * 6: touch(1) - Linux manual page - man7.org
Question 17
What is the default provider of Vagrant?
Correct Answer: C
Explanation Vagrant is a tool that allows users to create and configure lightweight, reproducible, and portable development environments. Vagrant supports multiple providers, which are the backends that Vagrant uses to create and manage the virtual machines. By default, VirtualBox is the default provider for Vagrant. VirtualBox is still the most accessible platform to use Vagrant: it is free, cross-platform, and has been supported by Vagrant for years. With VirtualBox as the default provider, it provides the lowest friction for new users to get started with Vagrant. However, users can also use other providers, such as VMware, Hyper-V, Docker, or LXC, depending on their preferences and needs. To use another provider, users must install it as a Vagrant plugin and specify it when running Vagrant commands. Users can also change the default provider by setting the VAGRANT_DEFAULT_PROVIDER environmental variable. References: * Default Provider - Providers | Vagrant | HashiCorp Developer1 * Providers | Vagrant | HashiCorp Developer2 * How To Set Default Vagrant Provider to Virtualbox3
Question 18
Which of the following commands deletes all volumes which are not associated with a container?
Correct Answer: C
Explanation The command that deletes all volumes which are not associated with a container is docker volume prune. This command removes all unused local volumes, which are those that are not referenced by any containers. By default, it only removes anonymous volumes, which are those that are not given a specific name when they are created. To remove both unused anonymous and named volumes, the --all or -a flag can be added to the command. The command will prompt for confirmation before deleting the volumes, unless the --force or -f flag is used to bypass the prompt. The command will also show the total reclaimed space after deleting the volumes12. The other commands listed in the question are not valid or do not have the same functionality as docker volume prune. They are either made up, misspelled, or have a different purpose. These commands are: * docker volume cleanup: This command does not exist in Docker. There is no cleanup subcommand for docker volume. * docker volume orphan -d: This command does not exist in Docker. There is no orphan subcommand for docker volume, and the -d flag is not a valid option for any docker volume command. * docker volume vacuum: This command does not exist in Docker. There is no vacuum subcommand for docker volume. * docker volume garbage-collect: This command does not exist in Docker. There is no garbage-collect subcommand for docker volume. References: * docker volume prune | Docker Docs * How to Remove all Docker Volumes - YallaLabs.
Question 19
Which of the following tasks are part of a hypervisor's responsibility? (Choose two.)
Correct Answer: C,E
Explanation A hypervisor is a software that creates and runs virtual machines (VMs) by separating the operating system and resources from the physical hardware. One of the main tasks of a hypervisor is to map the resources of VMs to the resources of the host system, such as CPU, memory, disk, and network. This allows the hypervisor to allocate and manage the resources among multiple VMs and ensure that they run efficiently and independently123. Another important task of a hypervisor is to isolate the VMs and prevent unauthorized access to resources of other VMs. This ensures the security and privacy of the VMs and their data, as well as the stability and performance of the host system. The hypervisor can use various techniques to isolate the VMs, such as virtual LANs, firewalls, encryption, and access control145. The other tasks listed are not part of a hypervisor's responsibility, but rather of the guest operating system or the application running inside the VM. A hypervisor does not create filesystems during the installation of new VMs, as this is done by the installer of the guest operating system6. A hypervisor does not provide host-wide unique PIDs to the processes running inside the VMs, as this is done by the kernel of the guest operating system7. A hypervisor does not manage authentication to network services running inside a VM, as this is done by the network service itself or by a directory service such as LDAP or Active Directory8. References: 1 (search for "What is a hypervisor?"), 2 (search for "How does a hypervisor work?"), 3 (search for "The hypervisor gives each virtual machine the resources that have been allocated"), 4 (search for "Benefits ofhypervisors"), 5 (search for "Isolate the virtual machines and prevent unauthorized access"), 6 (search for "Create filesystems during the installation of new virtual machine quest operating systems"), 7 (search for "Provide host-wide unique PIDs to the processes running inside the virtual machines"), 8 (search for "Manage authentication to network services running inside a virtual machine").
Question 20
What is the purpose of the commandvagrant init?
Correct Answer: C
Explanation The command vagrant init is used to initialize the current directory to be a Vagrant environment by creating an initial Vagrantfile if one does not already exist1. The Vagrantfile contains the configuration settings for the Vagrant box, such as the box name, box URL, network settings, synced folders, provisioners, etc. The command vagrant init does not execute any provisioning tool, start any box, install Vagrant on a Linux host, or download any box. Those actions are performed by other Vagrant commands, such as vagrant provision, vagrant up, vagrant install, and vagrant box add, respectively. References: * 1: vagrant init - Command-Line Interface | Vagrant | HashiCorp Developer
