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03-virtual-machine

3 min read

Proxmox VM

Quick Info

  • VMID: unique number between 100 and 999999999 (3-9 digits)
    • this can be renamed in /etc/pve/qemu-server/<VMID>.conf
  • Name: use hostname
  • After creation tasks: see VM Todo

VM Creation Checklist

1) System

  • Enable QEMU Agent so guest actions (shutdown, snapshot) work more reliably
  • BIOS:
    • Use OVMF when PCIe passthrough is needed
    • OVMF is UEFI compatible
    • Add EFI disk to preserve boot order
  • Machine Type:
    • i440fx or Q35 (Q35 required for PCIe passthrough)
  • SCSI Controller:
    • Prefer VirtIO SCSI

2) Hard Disk

Reference: https://blog.joeplaa.com/benchmark-proxmox-virtual-disk-settings/

  • Bus Device: SATA, VirtIO SCSI, or VirtIO-blk
  • Image Format:
    • qcow2: file-based, supports snapshots
    • raw: pre-allocated, better performance
  • Trim/Discard:
    • Keep ON so disk space can be reclaimed
    • Use discard on SSD storage (TRIM support)
    • Works with thin provisioning (unused blocks reclaimed after file deletion in guest)

3) Cache / Backup

  • Set disk to no backup if this VM disk should be excluded from VM backups

4) CPU

  • Total allocated vCPU across all VMs can exceed host physical cores (oversubscription)
  • Example: 4 VMs x 4 cores on an 8-core host is possible
  • Use CPU type host for passthrough and better performance

5) Memory

  • With PCI passthrough, RAM may be pre-allocated
  • Keep memory ballooning enabled unless there is a specific reason to disable it

6) Network

  • Bridge to vmbr0 for direct LAN access
  • Prefer VirtIO NIC for best performance (better than Realtek/E1000 emulation)

Windows VM Notes

Reference: https://pve.proxmox.com/wiki/Windows_10_guest_best_practices

VM Todo

Linux

Install QEMU Guest Agent

Restart the VM after installation.

sudo apt update
sudo apt install qemu-guest-agent

Remote Access (Linux GUI)

SSH or Proxmox WebUI shell is usually enough for terminal access. For GUI workloads, SPICE is often better than the default console.

Client (Windows)

Install Virt-Viewer:
https://gitlab.com/virt-viewer/virt-viewer/-/releases/v11.0/downloads/virt-viewer-x64-11.0-1.0.msi

Guest VM (Linux)

  • Change Display to SPICE
  • Shut down and start the VM
  • Open Console to download the .vv file
  • Open the .vv file with Virt-Viewer

Frozen Display on Ubuntu 24.04

If SPICE display freezes, change Display to VirtIO-GPU.

Guest VM (Windows)

Download SPICE client: https://www.spice-space.org/download/windows/spice-guest-tools/spice-guest-tools-latest.exe

Fix Code 53 on Windows Server

https://askubuntu.com/questions/1508638/qemu-kvm-windows-11-code-52-error-with-display-driver
Download the third file.
In windows, uninstall the QXL driver (may need to switch to default display) and manually load the driver from folder.

Cloud-Init Templates

Prepare Linux Cloud-Init Template

  1. Verify cloud-init is installed
  2. Edit /etc/cloud/cloud.cfg
  3. Install whois to use mkpasswd
  4. Generate password hash with mkpasswd -m sha-512

Example cloud-init snippet:

users:
  - default
  - name: name_of_user
    lock_passwd: false
    passwd: {password_hash}
    gecos: Name
    groups: sudo
    sudo: ["ALL=(ALL) NOPASSWD:ALL"]
    shell: /bin/bash
 
timezone: "America/Vancouver"
 
packages:
  - package_name

Clean VM Before Converting to Template

  1. Remove SSH host keys: cd /etc/ssh && sudo rm ssh_host_*
  2. Reset machine ID: sudo truncate -s 0 /etc/machine-id
  3. Ensure /var/lib/dbus/machine-id links to /etc/machine-id
  4. If needed, recreate symlink: sudo ln -sf /etc/machine-id /var/lib/dbus/machine-id
  5. Clean package cache: sudo apt clean && sudo apt autoremove -y
  6. Confirm cloud-init config and package list

Convert VM to Template

  • Detach ISO
  • Add CloudInit drive and choose storage location
  • In Cloud-Init settings, define username/password or SSH key

Clone from Template

  • Full Clone: full copy of template (independent)
  • Linked Clone: lower storage use, depends on base template

Graph View

Recent Notes

Backlinks