Creating a VM Template with cloud-init in Proxmox

In this note, we will import a previously prepared OS image in qcow2 format into Proxmox as a VM template using QEMU console commands.

All examples from the article were performed in the Proxmox 9 hypervisor environment (Debian 13).

1️⃣ Connect to the Proxmox server via SSH:

ssh root@proxmox.home.lan

2️⃣ Resize the disk (specify a suitable value for your case):

qemu-img resize ./debian-13-generic-amd64.qcow2 20G

3️⃣ Create a new virtual machine with any name, for example debian13-k8s-template, an ID, for example 7777, and basic settings (adjust them for your environment):

qm create 7777 --name "debian13-k8s-template" \
    --memory 2048 --cores 2 --net0 virtio,bridge=vmbr0

4️⃣ Import the debian-13-generic-amd64.qcow2 disk image into the storage storage (replace it with your own) and attach it to the VM with ID 7777:

qm importdisk 7777 ./debian-13-generic-amd64.qcow2 storage --format qcow2

5️⃣ Set the SCSI controller and add the imported disk as scsi0:

qm set 7777 --scsihw virtio-scsi-single \
    --scsi0 storage:7777/vm-7777-disk-0.qcow2

6️⃣ Set the boot order, specifying scsi0 as the first boot disk:

qm set 7777 --boot order=scsi0

7️⃣ Add a cloud-init disk to the virtual machine as ide0 (for automatic configuration on first boot):

qm set 7777 --ide0 storage:cloudinit

8️⃣ Configure the user, password, and SSH for cloud-init:

# User creation
qm set 7777 --ciuser ivan
qm set 7777 --cipassword $(openssl passwd -6)

# IP configuration
qm set 7777 --ipconfig0 ip=dhcp
# or static
qm set 7777 --ipconfig0 ip=192.168.1.100/24,gw=192.168.1.1

# Adding an SSH key
qm set 7777 --sshkeys ~/.ssh/id_ed25519.pub

ssh-keygen -t ed25519 -f ~/.ssh/id_ed25519

More about cloud-init scenarios

To use all cloud-init capabilities, you need to use an external scenario file in yaml format.

You can attach it with this command:

BASH

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qm set 7777 --cicustom "user=storage:snippets/cloud_init.yml"

Click to expand and view more

Note that the specified storage (in my example, storage) must have the Snippets content type enabled in Proxmox:

Example cloud_init.yml:

cloud_init.yml

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hostname: debian-13-k8s
manage_etc_hosts: true
users:
  - name: ivan
    groups: sudo
    shell: /usr/bin/bash
    sudo: ['ALL=(ALL) NOPASSWD:ALL']
    ssh_authorized_keys:
      - ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIL8aS3Z5q70yiRgZkJbknB2ROiTl9vo+HGGF9Pgc9eF9 root@proxmox
chpasswd:
  list: |
    ivan:MySecretPassword123
  expire: false
package_update: true
package_upgrade: true
packages:
  - apt-transport-https
  - ca-certificates
  - curl
  - containerd
  - gpg
runcmd:
  - echo "overlay" > /etc/modules-load.d/k8s.conf
  - echo "br_netfilter" >> /etc/modules-load.d/k8s.conf
  - modprobe overlay && modprobe br_netfilter
  - containerd config default > /etc/containerd/config.toml
  - sed -i '/SystemdCgroup/s/false/true/' /etc/containerd/config.toml
  - systemctl restart containerd

Click to expand and view more

9️⃣ Configure the serial port for the console and the video adapter linked to it:

qm set 7777 --serial0 socket --vga serial0

🔟 Enable QEMU Guest Agent for interaction between the host and the guest system:

qm set 7777 --agent enabled=1

1️⃣1️⃣ Convert the virtual machine into a template (for cloning and quick deployment):

qm template 7777

1️⃣2️⃣ Rescan the virtual machine configuration (may be useful after making changes):

qm rescan --vmid 7777

1️⃣3️⃣ View the full configuration of our virtual machine template:

qm config 7777

1️⃣4️⃣ Check the list of files in the VM directory (storage storage), in my case this is: /mnt/storage/images/7777/:

ls -l /mnt/storage/images/7777/

We can see the image itself and the cloud-init disk👌.

qm destroy 7777

1️⃣5️⃣ Now calmly clone your template into a new virtual machine in Proxmox:

1️⃣6️⃣ After startup, check access to the new VM console by password:

1️⃣7️⃣ Check SSH key connection:

Everything works!

In the next article, we will automate infrastructure deployment in Proxmox using Terraform/OpenTofu. Do not miss it👨‍💻.

Thank you for reading! Good luck😉.

👨‍💻Ну и…

Don’t forget about our Telegram channel 📱 and chat 💬 All the best ✌️

That should be it. If not, check the logs 🙂