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

The qm pending command is an integral tool within the Proxmox Virtual Environment (PVE) that allows administrators to retrieve the configuration of a virtual machine (VM), displaying both the current and pending values. This is particularly useful when changes have been queued to take effect after a device restart, providing insight into both active settings and upcoming modifications. This dual-visibility allows for better planning and management of virtual machines, ensuring that system administrators can verify configurations before confirming alterations.

Use Case: Get the Virtual Machine Configuration of a Specific Virtual Machine

Code:

qm pending vm_id

Motivation:

In virtualized environments, administrators often need to manage and configure multiple virtual machines. Each VM may require specific settings such as CPU, memory, and storage adjustments based on the workload demands. When changes are proposed, they sometimes cannot be immediately applied without stopping the VM, thus queued as pending changes. By using the qm pending command for a specific VM, administrators can preview these pending changes alongside the current settings, enabling them to anticipate the impact of these updates upon the next VM restart. This foresight helps in resource planning and maintaining service continuity, preventing unexpected issues post-implementation.

Explanation:

• qm: This is the command-line tool used in Proxmox, specifically for managing QEMU/KVM virtual machines. It provides various functions including starting, stopping, and configuring VMs.

• pending: This argument directs the command to fetch both current and queued configuration values from the system. It distinguishes from the standard configuration which only depicts active settings.

• vm_id: This is a placeholder for the unique identifier assigned to each virtual machine. By specifying vm_id, the command targets the particular VM whose configuration details you wish to inspect. Every VM in a Proxmox environment is allocated a unique ID for precise management.

Example Output:

VM 101 pending configuration changes:
  memory: 4096 -> 8192
  cpu: 2 -> 4
  net0: virtio=00:11:22:33:44:55 -> virtio=00:11:22:33:44:66

In this example, the command reveals that upon the next restart, the memory for the virtual machine with ID 101 will be increased from 4096 MB to 8192 MB, the number of CPUs will double from 2 to 4, and the network interface will have a change in its MAC address. Such visibility is invaluable in ensuring that the configuration changes align with intended resource adjustments and system requirements.

Conclusion:

The qm pending command is a potent tool in the arsenal of a system administrator working within a Proxmox environment. It provides critical insights into the configuration states of virtual machines, ensuring that both current and on-schedule changes are visible upfront. This transparency allows proactive management and adjustment of resources to meet operational demands and prevent disruptions. By understanding and utilizing qm pending, administrators can significantly enhance the reliability and efficiency of their virtual environments.