LPI 305-300 Exam With Confidence Using Practice Dumps

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

 LXC and Docker are both container technologies that use Linux kernel features to create isolated environments for running applications. The main mechanisms that they use are:

• Linux Capabilities: These are a set of privileges that can be assigned to processes to limit their access to certain system resources or operations. For example, a process with the CAP_NET_ADMIN capability can perform network administration tasks, such as creating or deleting network interfaces. Linux capabilities allow containers to run with reduced privileges, enhancing their security and isolation.
• Kernel Namespaces: These are a way of creating separate views of the system resources for different processes. For example, a process in a mount namespace can have a different file system layout than the host or other namespaces. Kernel namespaces allow containers to have their own network interfaces, process IDs, user IDs, and other resources, without interfering with the host or other containers.
• Control Groups: These are a way of grouping processes and applying resource limits and accounting to them. For example, a control group can limit the amount of CPU, memory, disk I/O, or network bandwidth that a process or a group of processes can use. Control groups allow containers to have a fair share of the system resources and prevent them from exhausting the host resources.

POSIX ACLs and file system permissions are not mechanisms used by LXC and Docker to create containers. They are methods of controlling the access to files and directories on a file system, which can be applied to any process, not just containers.

References:

• LXC vs Docker: Which Container Platform Is Right for You?
• LXC vs Docker: Why Docker is Better in 2023 | UpGuard
• What is the Difference Between LXC, LXD and Docker Containers
• lxc - Which container implementation docker is using - Unix & Linux Stack Exchange

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.