The ‘virsh-undefine’ command is used to delete a virtual machine. It allows you to delete the virtual machine configuration file as well as any associated storage volumes. This can be useful when you no longer need a virtual machine and want to free up resources on your system.

Use case 1: Delete only the virtual machine configuration file

virsh undefine --domain vm_name

Motivation: When you want to remove a virtual machine but keep the storage volumes associated with it, you can use this command. This can be useful if you want to create a new virtual machine with the same storage volumes at a later time.

Explanation:

• ‘undefine’ is the subcommand of the ‘virsh’ command that is used to delete a virtual machine.
• ‘–domain’ is the option used to specify the name of the virtual machine you want to delete.
• ‘vm_name’ is the name of the virtual machine you want to delete. Replace this with the actual name of the virtual machine.

Example OUTPUT:

Domain vm_name has been undefined

Use case 2: Delete the configuration file and all associated storage volumes

virsh undefine --domain vm_name --remove-all-storage

Motivation: When you no longer need a virtual machine and want to completely remove it, including all the associated storage volumes, you can use this command. This can be useful when you want to reclaim disk space on your system.

Explanation:

• ‘–remove-all-storage’ is the option used to specify that you want to delete all the storage volumes associated with the virtual machine, in addition to the configuration file.

Example OUTPUT:

Domain vm_name has been undefined and all associated storage volumes have been removed.

Use case 3: Delete the configuration file and specified storage volumes

virsh undefine --domain vm_name --storage sda,path/to/source

Motivation: When you want to delete a specific storage volume associated with a virtual machine, you can use this command. This can be useful when you have multiple storage volumes and only want to delete some of them.

Explanation:

• ‘–storage’ is the option used to specify the storage volume you want to delete.
• ‘sda’ is the target name or source name of the storage volume you want to delete. Replace this with the actual name of the storage volume.
• ‘path/to/source’ is the path to the source file of the storage volume you want to delete. Replace this with the actual path of the source file.

Example OUTPUT:

Domain vm_name has been undefined and the specified storage volume has been removed.

Conclusion:

The ‘virsh-undefine’ command is a versatile tool for deleting virtual machines. It allows you to delete the virtual machine configuration file and associated storage volumes, giving you control over the resources used by your virtual machines. Whether you want to delete only the configuration file, remove all storage volumes, or delete specific storage volumes, the ‘virsh-undefine’ command provides the flexibility you need.