How to Use the Command 'qm clone' (with examples)

The qm clone command, part of the Proxmox Virtual Environment (Proxmox VE), is a powerful tool used to create a duplicate or a new instance of a virtual machine. This functionality is critical in virtualized environments for testing, load balancing, or managing different environments without impacting production instances. By using the qm clone command, administrators can efficiently handle multiple virtual machine configurations, names, storage formats, and pool allocations, ultimately optimizing their virtualized systems.

Use case 1: Copy a virtual machine

Code:

qm copy vm_id new_vm_id

Motivation:

In environments where multiple instances of a virtual machine (VM) are needed, duplicating a VM quickly becomes essential. By using this command, administrators can efficiently create clones of existing VMs for purposes like testing new software, conducting experiments without affecting the original setup, or distributing workloads among different hosts.

Explanation:

• qm: This begins the command sequence specifying that we’re using the VM management utilities of Proxmox.
• copy: This sub-command tells Proxmox to make a duplicate of a VM.
• vm_id: The identifier of the source VM that you wish to copy.
• new_vm_id: The identifier for the new VM clone.

Example Output:

Upon running this command, a new virtual machine with the specified new_vm_id is created, which mirrors the settings of the original virtual machine.

Use case 2: Copy a virtual machine using a specific name

Code:

qm copy vm_id new_vm_id --name name

Motivation:

In scenarios where clarity and organization are crucial, having a descriptive name for each VM helps in quickly identifying and managing resources. Naming VMs logically supports team collaboration and streamline routine maintenance tasks.

Explanation:

• qm copy vm_id new_vm_id: As before, these are the basic commands to duplicate a VM.
• --name name: This option allows you to specify a human-readable name for the cloned VM. This is useful for identifying the specific role or purpose of the VM, such as “TestServer” or “DevEnvironment.”

Example Output:

The cloned VM appears in the Proxmox environment with the specified name, making it easy to locate and organize among other VMs.

Use case 3: Copy a virtual machine using a specific description

Code:

qm copy vm_id new_vm_id --description description

Motivation:

Providing a description for a virtual machine is helpful for documenting its intended use or configuration details. This is beneficial when multiple administrators manage VMs, ensuring quick understanding of what each VM is used for.

Explanation:

• qm copy vm_id new_vm_id: These elements are used to initiate the copy process.
• --description description: This allows the user to attach a detailed explanation or note to the new VM for future reference.

Example Output:

The cloned VM is now accompanied by descriptive metadata that can be viewed in the Proxmox management interface, providing context into its use case or configuration.

Use case 4: Copy a virtual machine creating a full copy of all disks

Code:

qm copy vm_id new_vm_id --full

Motivation:

Using a full copy is essential when a complete snapshot of the entire disk content is needed for backup, migration, or testing purposes without affecting the original VM’s performance or data.

Explanation:

• qm copy vm_id new_vm_id: Initiates a standard VM duplication.
• --full: This argument forces the clone operation to create a full disk copy, not just a linked clone. This means it duplicates all data and settings, ensuring the clone is entirely independent from the source VM.

Example Output:

The complete disk image of the original VM is replicated onto the new VM, making it stand-alone and unaffected by any changes to the source VM.

Use case 5: Copy a virtual machine using a specific format for file storage (requires --full)

Code:

qm copy vm_id new_vm_id --full --format qcow2|raw|vmdk

Motivation:

Selecting a specific storage format when cloning a VM helps in meeting compatibility requirements with different virtualization platforms or storage configurations. Different formats have varied features such as improved performance or better compression.

Explanation:

• qm copy vm_id new_vm_id --full: Initiates a full copy of all VM disk data.
• --format qcow2|raw|vmdk: Specifies the disk image format. qcow2 offers features like compression and snapshots; raw provides better performance; and vmdk ensures compatibility with VMware products.

Example Output:

You receive a cloned VM with a disk in the specified format, which can then be integrated or used as required by different storage strategies or platform compatibilities.

Use case 6: Copy a virtual machine then add it to a specific pool

Code:

qm copy vm_id new_vm_id --pool pool_name

Motivation:

Assigning VMs to specific pools helps in organizing and managing resources based on function, department, or other criteria. This is particularly useful in large environments to systematically allocate resources.

Explanation:

• qm copy vm_id new_vm_id: Initiates the VM cloning process.
• --pool pool_name: This designates the resource pool where the cloned VM will be assigned, aiding in better resource management and allocation.

Example Output:

The new VM is cloned and immediately assigned to the specified pool, appearing under its designated resource category in the Proxmox VE interface.

Conclusion:

Using the qm clone command in Proxmox VE enables system administrators to manage VMs efficiently through cloning, naming, describing, formatting, and pooling functionalities. Mastering these commands can lead to improved operational efficiency and better resource management in virtualized environments.