Installing every VM from an ISO wastes time. With Proxmox templates you prepare one VM, convert it into a read-only template and clone it whenever you need a new server. The main choice is between linked and full clones.
Before you start
- A VM with the OS installed, updated and with the QEMU guest agent (create a VM).
- For cloud images with automatic IP and SSH key setup, see cloud-init templates.
Prepare the VM
- Install updates and your standard tools.
- Remove unique identifiers so clones do not clash. On Linux:
truncate -s 0 /etc/machine-id && rm -f /var/lib/dbus/machine-idrm -f /etc/ssh/ssh_host_*Make sure SSH host keys are regenerated on first boot (Debian/Ubuntu: dpkg-reconfigure openssh-server in a first-boot script, or cloud-init does it for you). On Windows, run Sysprep with Generalize and shut down.
- Shut down the VM.
Convert to a Proxmox template
Right-click the VM and choose Convert to template, or run qm template 9000. Templates cannot be started, which protects them from changes.
Linked clone vs full clone
| Linked clone | Full clone | |
|---|---|---|
| Creation speed | Seconds | Copies the whole disk |
| Disk space | Only stores changes | Full size per VM |
| Depends on template | Yes, template cannot be deleted | No, fully independent |
| Storage | Needs snapshot-capable storage (LVM-thin, ZFS, Ceph, qcow2) | Any |
| Best for | Labs, test VMs, short-lived servers | Production servers |
Clone a template
- Right-click the template → Clone.
- Set the new VM ID and name, and choose Mode: Linked Clone or Full Clone.
- For full clones, choose the target storage.
- Click Clone, then adjust CPU, RAM and network before starting.
qm clone 9000 130 --name app1 --fullTip: Rebuild your template every few months with fresh updates so new VMs do not start out of date.
Troubleshooting
- Clones have the same IP from DHCP: the machine ID was not cleared before templating.
- Linked clone option missing: the template's storage does not support it.
- Cannot delete template: linked clones still depend on it.
Frequently asked questions
Can I edit a template later?
Clone it to a VM, change it, and convert that VM into a new template.
Are containers cloned the same way?
Yes, LXC containers can be templates and cloned too.
Should production VMs be linked clones?
Full clones are safer, since they do not depend on the template's disk.