Create a VM and a cloud-init template with qm

The web UI wizard is the easiest way to create one VM. When you create many, the qm command and a cloud-init template are much faster: you prepare one VM from a distribution’s cloud image, turn it into a template, and clone new VMs that configure their user, SSH key and network on first boot.

Part 1: a VM from an ISO

Upload the installer ISO to a storage that allows ISO images (the default local storage does). Then create the VM. Disk sizes use the syntax STORAGE:SIZE_IN_GiB, which allocates a new volume; memory is in MiB.

qm create 110 --name web01 --ostype l26 \
  --memory 2048 --cores 2 \
  --scsihw virtio-scsi-pci --scsi0 local-lvm:32 \
  --net0 virtio,bridge=vmbr0 \
  --cdrom local:iso/debian-13-netinst.iso \
  --boot 'order=scsi0;ide2'

qm start 110

Open the console in the web UI to run the installer. Useful follow-up commands:

qm config 110          # show the configuration
qm shutdown 110 && qm wait 110
qm set 110 --onboot 1  # start automatically with the host
qm set 110 --agent enabled=1

--agent enabled=1 tells Proxmox VE to talk to the QEMU guest agent. Install the qemu-guest-agent package inside the guest; the setting takes effect after a fresh start of the VM. The agent lets the host shut down the guest cleanly, read its IP addresses and freeze file systems during backups.

Part 2: build a cloud-init template

Many distributions publish cloud images that already contain cloud-init. The following steps follow the official example. Replace the image file with the one you download, and the storage names with your own.

1. Download a cloud image to the node, for example from your distribution’s cloud image site, into a folder such as /root/images.
2. Create an empty VM with a VirtIO SCSI controller: qm create 9000 --name tpl-cloud --memory 2048 --net0 virtio,bridge=vmbr0 --scsihw virtio-scsi-pci
3. Import the image as the first SCSI disk: qm set 9000 --scsi0 local-lvm:0,import-from=/root/images/IMAGE.img
4. Add the cloud-init drive, which passes user and network settings to the guest: qm set 9000 --ide2 local-lvm:cloudinit
5. Boot only from the imported disk: qm set 9000 --boot order=scsi0
6. Many cloud images expect a serial console: qm set 9000 --serial0 socket --vga serial0. If the image does not show output this way, switch back to the default display.
7. Convert the VM to a template: qm template 9000

qm create 9000 --name tpl-cloud --memory 2048 --net0 virtio,bridge=vmbr0 --scsihw virtio-scsi-pci
qm set 9000 --scsi0 local-lvm:0,import-from=/root/images/IMAGE.img
qm set 9000 --ide2 local-lvm:cloudinit
qm set 9000 --boot order=scsi0
qm set 9000 --serial0 socket --vga serial0
qm template 9000

A template cannot be started. It is read-only and serves as the source for clones.

Part 3: deploy VMs from the template

qm clone 9000 123 --name app01
qm set 123 --ciuser admin --sshkeys /root/.ssh/admin.pub
qm set 123 --ipconfig0 ip=192.0.2.123/24,gw=192.0.2.1
qm disk resize 123 scsi0 +18G
qm start 123

• Without --full, cloning a template creates a linked clone, which shares unchanged data with the template and is created almost instantly. It needs a storage that supports it (for example LVM-thin, ZFS, Ceph or qcow2 files) and depends on the template, so you cannot delete the template while linked clones exist. Add --full for an independent copy.
• --ipconfig0 ip=dhcp uses DHCP instead of a static address.
• qm disk resize only grows disks; with + the value is added to the current size. Most cloud images grow their root file system automatically on boot.
• qm cloudinit dump 123 user shows the generated cloud-init user data, which helps when a setting does not seem to apply. After changing cloud-init options on an existing VM, qm cloudinit update 123 regenerates the drive.

Removing a VM

Warning: qm destroy permanently deletes the VM and all disks it owns. First check that you have the right ID with qm config <vmid> and that a recent backup exists. Add --purge to also remove the VM from backup jobs, replication jobs and HA configuration.

qm config 123 | head
qm destroy 123 --purge

Official documentation

• qm(1): QEMU/KVM Virtual Machine Manager, including Cloud-Init support