Using `virsh-domblklist` Command (with examples)
Introduction
The virsh-domblklist command is a powerful tool used to list information about block devices associated with a virtual machine. It provides details such as the target name, source path, disk type, and device value. In this article, we will explore two different use cases of this command and provide code examples, motivations, explanations for each argument, and example outputs.
Use Case 1: List Target Name and Source Path
Sometimes, we may need to know the target name and source path of the block devices associated with a virtual machine. The virsh-domblklist command allows us to easily retrieve this information.
Code:
virsh domblklist --domain vm_name
Motivation:
Knowing the target name and source path of block devices can be useful for various purposes. For example, it can help us in troubleshooting storage-related issues, identifying where the virtual machine’s disks are stored, or determining the specific disk being accessed by the virtual machine.
Explanation:
virsh: The command itself.domblklist: The subcommand for listing block devices.--domain vm_name: The argument specifying the domain (virtual machine) name for which we want to list the block devices.
Example Output:
Target Source
------------------------------------------------
vda /var/lib/libvirt/images/vm_disk.img
Use Case 2: List Disk Type, Device Value, Target Name, and Source Path
In addition to the target name and source path, it might be necessary to obtain further information about the block devices, such as the disk type and device value. The virsh-domblklist command also allows us to gather these details.
Code:
virsh domblklist --domain vm_name --details
Motivation:
By including the disk type and device value in the output, we can gain a deeper understanding of the virtual machine’s block devices. This information can be helpful for tasks such as disk management, capacity planning, or identifying non-standard disk configurations.
Explanation:
virsh: The command itself.domblklist: The subcommand for listing block devices.--domain vm_name: The argument specifying the domain (virtual machine) name for which we want to list the block devices.--details: The argument requesting additional details about each block device.
Example Output:
Type Device Target Source
----------------------------------------
disk vda /var/lib/libvirt/images/vm_disk.img
Conclusion
The virsh-domblklist command provides a straightforward way to obtain information about block devices associated with a virtual machine. By using the --domain option, we can specify the virtual machine and retrieve details such as the target name, source path, disk type, and device value. Understanding how to utilize this command and its options can greatly assist in managing virtual machine storage, troubleshooting storage-related issues, and performing various administrative tasks.
