qm-start

Start a specific virtual machine

$ qm start [100]

$ qm start [100] --machine [q35]

$ qm start [100] --timeout [60]

qm start <vmid> [OPTIONS]

Arguments:
<vmid>       The unique numeric ID of the virtual machine or container to start.

--timeout
    Maximum startup time in seconds. If the VM/CT does not start within this period, the command exits with an error. Defaults to 300 seconds (5 minutes).

--force
    Ignores and clears existing locks (e.g., if a previous task failed or was interrupted). Use with caution, as it can lead to inconsistent states.

--skiplock
    Skips checking for locks, allowing the command to proceed even if another operation might be in progress. Less aggressive than --force.

--stateless
    Starts the VM in stateless mode. All changes made during the session are discarded on shutdown, reverting to the last saved state or a snapshot. This is primarily for QEMU/KVM VMs.

--digitalsign
    Specifies a digital signature for secure boot. Rarely used in typical scenarios.

The qm-start command is a crucial utility within the Proxmox Virtual Environment (PVE) suite, designed to initiate the operation of virtual machines (VMs) and containers (CTs). It leverages QEMU/KVM for VMs and LXC for containers, providing a unified command-line interface for managing their lifecycle. When invoked, qm-start checks the specified VM or CT ID, allocates necessary resources based on its configuration (CPU, memory, storage, network), and then powers it on. This command is fundamental for bringing virtualized workloads online after creation, after a graceful shutdown, or following a power outage. It ensures that the guest operating system within the VM or CT begins its boot sequence, making the virtualized environment accessible and operational. The command typically returns successfully once the boot process has begun, not necessarily when the guest OS is fully loaded.

Starting a VM or CT requires sufficient host resources (CPU, RAM, storage). If resources are over-provisioned or unavailable, the command may fail or the VM/CT may not boot properly. The command will fail if the specified VMID does not exist or if the VM/CT is already running. Using --force should be done with extreme care, as it can bypass critical safety checks and potentially lead to data corruption or inconsistent states.

The command typically returns immediately after the VM or CT boot process has been initiated on the host. It does not wait for the guest operating system inside the VM/CT to fully boot or become accessible. To check the actual runtime status, use qm status <vmid>.

While qm-start initiates a VM/CT manually, Proxmox VE also provides an autostart feature (usually configured per VM/CT in the GUI or via qm set). This allows VMs/CTs to automatically start with the host system or when the host node reboots, ensuring high availability and ease of management for critical services.

The qm-start command is an integral part of the Proxmox Virtual Environment (PVE) command-line interface, which was first released in 2007. As Proxmox VE evolved into a leading open-source virtualization platform, the qm utility became the primary tool for managing QEMU/KVM virtual machines and LXC containers. qm-start has been a core component since the early days, adapting to new features and technologies within the virtualization stack, consistently providing a robust way to bring virtualized workloads online. Its design reflects Proxmox's philosophy of offering powerful, enterprise-grade virtualization management through a straightforward command-line interface.

qm stop(1)       Stop a virtual machine or container gracefully., qm shutdown(1)       Request a graceful shutdown of a virtual machine or container., qm status(1)       Get the current status of a virtual machine or container., qm list(1)       List all virtual machines and containers., qm(1)       The main Proxmox VE VM/CT management utility.