305-300 Exam Dumps : LPIC-3: Virtualization and Containerization - Exam 305, version 3.0

The command lxc-attach is used to execute a command in a running LXC container. It allows the user to start a process inside the container and attach to its standard input, output, and error streams1. For example, the command lxc-attach -n mycontainer -- ls -lh /home will list all the files and directories in the /home directory of the container named mycontainer1. The other options are not valid LXC commands. The command lxc-batch does not exist. The command lxc-run is an alias for lxc-start, which is used to start a container, not to execute a command in it2. The command lxc-enter is also an alias for lxc-attach, but it is deprecated and should not be used3. The command lxc-eval is also not a valid LXC command. References:

• 1: Executing a command inside a running LXC - Unix & Linux Stack Exchange.
• 2: lxc-start: start a container. - SysTutorials.
• 3: lxc-attach: start a process inside a running container. - SysTutorials.

The output of xl list shows the state of the domains. The domain with ID 6, Ubuntu, has a state of “b—”. This means that the domain is blocked, which means it is idle or waiting for I/O.

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