Proxmox Ubuntu VM Template Setup Guide - Cloud-Init Integration

This guide walks you through creating a reusable Ubuntu VM template in Proxmox using cloud-init. This approach allows for rapid deployment of VMs with automatic configuration, making it perfect for scaling infrastructure quickly.

Prerequisites

• Proxmox VE installed and configured
• Access to the Proxmox web interface and shell
• At least 1GB RAM and 10GB storage available per VM
• Internet connection for downloading Ubuntu cloud image

Tip

This guide uses Ubuntu 24.04 LTS minimal cloud image for optimal performance and smaller footprint. Cloud-init enables automatic configuration on first boot.

Step 1: Create the Base VM

1. Create new VM

   • Click “Create VM” in the Proxmox interface
   • Configure the VM with the following settings:
     • VM ID: Choose an available ID (e.g., 900)
     • Name: ubuntu-2404-template
     • Resource Pool: (optional)

2. OS Configuration

   • Guest OS: Linux
   • Version: 6.x - 2.6 Kernel
   • Do not use any media: ✅ Enabled

   Note

   We’re not using installation media because we’ll import a pre-built cloud image instead.

3. System Settings

   • BIOS: Default (SeaBIOS)
   • Machine: Default (i440fx)
   • SCSI Controller: VirtIO SCSI single
   • Qemu Agent: ✅ Enabled

4. Hard Disk Configuration

   • Skip this step - delete any disk that was created
   • We’ll add the cloud image disk later

5. CPU Configuration

   • Sockets: 1
   • Cores: 1 (can be increased when cloning)
   • Type: x86-64-v2-AES (modern CPU features)

6. Memory Configuration

   • Memory: 1024 MB (can be increased when cloning)

7. Network Configuration

   • Bridge: vmbr0 (or your configured bridge)
   • Model: VirtIO (paravirtualized network driver)
   • Firewall: ✅ Enabled (optional but recommended)

Step 2: Configure Cloud-Init

1. Add Cloud-Init drive

   • Navigate to the Hardware tab of your newly created VM
   • Click Add → CloudInit Drive
   • Select your preferred storage location
   • Click Add

2. Configure Cloud-Init settings

   • Go to the Cloud-Init tab in your VM
   • Configure the following essential settings:
     • User: Set your desired username (e.g., ubuntu)
     • Password: Set a secure password
     • SSH Public Key: Paste your SSH public key (optional)
     • DNS domain: Optional (e.g., local)
     • DNS servers: Optional (e.g., 8.8.8.8 1.1.1.1)

3. Network Configuration

   • Set IP Config to DHCP

   Tip

   Even if you plan to use static IPs for your VMs, set this to DHCP for the template. You’ll configure static IPs when cloning.

4. Regenerate Cloud-Init image

   • Click Regenerate Image to apply your configuration
   • This creates the cloud-init configuration disk

Step 3: Download and Import Ubuntu Cloud Image

1. Access Proxmox shell

   • Click on your Proxmox node in the left panel
   • Navigate to Shell or SSH into your Proxmox host

2. Download Ubuntu cloud image

   # Download Ubuntu 24.04 LTS minimal cloud image
   wget https://cloud-images.ubuntu.com/minimal/releases/noble/release/ubuntu-24.04-minimal-cloudimg-amd64.img

   Note

   The minimal cloud image is smaller and boots faster than the full cloud image, making it perfect for templates.

3. Resize the image

   # Resize to 32GB (adjust as needed)
   qemu-img resize ubuntu-24.04-minimal-cloudimg-amd64.img 32G

4. Add serial console for cloud-init output

   # Replace VM-ID with your VM ID (e.g., 900)
   qm set VM-ID --serial0 socket --vga serial0

   Tip

   This enables serial console output, which is helpful for debugging cloud-init and boot processes.

5. Import the image to your VM

   # Replace VM-ID with your VM ID (e.g., 900)
   # Replace 'local-lvm' with your storage if different
   qm disk import VM-ID ubuntu-24.04-minimal-cloudimg-amd64.img local-lvm

6. Attach the imported disk

   • Return to the Proxmox web interface
   • Go to your VM’s Hardware tab
   • You’ll see an Unused Disk - double-click it to edit
   • Configure the disk settings:
     • Bus/Device: SCSI 0
     • Cache: Default
     • Discard: ✅ Enabled (if using SSD storage)
     • SSD emulation: ✅ Enabled (if using SSD storage)
   • Click Add to attach the disk

7. Clean up downloaded file

   # Remove the downloaded image file to save space
   rm ubuntu-24.04-minimal-cloudimg-amd64.img

Step 4: Final Configuration and Template Creation

1. Configure boot order

   • Go to Options tab in your VM
   • Double-click Boot Order
   • Ensure the imported disk is first in the boot order
   • Enable the disk if it’s not already enabled
   • Click OK

2. Configure additional options

   • Start at boot: ✅ Enable if you want VMs to auto-start (optional)

3. Optional: Pre-configure the template with additional software

   • If you want to customize the template before converting it, boot the VM
   • Login using the cloud-init credentials you configured
   • Install and configure additional software as needed:

   # Update package repositories and upgrade system
   sudo apt update && sudo apt upgrade -y
   
   # Install SSH import utility for GitHub key management
   sudo apt install -y ssh-import-id
   ssh-import-id gh:YOUR-GITHUB-USERNAME
   
   # Install QEMU guest agent for better VM integration
   sudo apt install -y qemu-guest-agent
   sudo systemctl enable --now qemu-guest-agent
   
   # Install commonly needed packages
   sudo apt install -y curl wget git vim htop
   
   # Clean up package cache and unnecessary packages
   sudo apt -y autoremove --purge
   sudo apt -y clean
   
   # Prepare template for cloning - clean cloud-init state
   sudo cloud-init clean -s -l
   sudo truncate -s 0 /etc/machine-id
   sudo truncate -s 0 /var/lib/dbus/machine-id
   
   # Clean potential DHCP leases
   sudo rm -f /var/lib/dhcp/*
   
   # Shutdown the VM
   sudo shutdown -h now

   Note

   This step is optional but recommended if you want a template with commonly used software pre-installed. The cleaning commands ensure the template can be properly cloned.

4. Convert to template

   • Right-click on your VM in the resource tree
   • Select Convert to template
   • Confirm the conversion

5. Verify template creation

   • The VM should now show a template icon
   • The template is ready for cloning

Step 5: Using Your Template

1. Clone the template

   • Right-click on your template
   • Select Clone
   • Configure the clone:
     • VM ID: New unique ID
     • Name: Descriptive name for your new VM
     • Mode: Full clone (recommended)
     • Target Storage: Choose appropriate storage

2. Configure the cloned VM

   • Hardware: Adjust CPU, memory, and disk size as needed
   • Cloud-Init: Update user credentials, network config, SSH keys
   • Options: Configure boot order, protection, etc.

3. Customize cloud-init for the clone

   # Example: Configure static IP
   # In the Cloud-Init tab, set IP Config to Manual:
   # IP: 192.168.1.100/24
   # Gateway: 192.168.1.1
   # DNS: 8.8.8.8 1.1.1.1

4. Start your new VM

   • Start the VM
   • Cloud-init will automatically configure the system on first boot
   • SSH into the VM using the credentials you configured