How to Create a Virtual Machine in Proxmox

Proxmox VE is a powerful open-source hypervisor that lets you run multiple virtual machines on a single physical host. Whether you’re a UK-based IT administrator setting up a test environment, a developer who needs an isolated sandbox, or a small business owner wanting to trial software without touching a production machine, creating a VM in Proxmox is a straightforward process once you understand the wizard. This guide walks you through everything from uploading your ISO to taking your first snapshot.

Upload an ISO to Proxmox Local Storage

1. Log in to the Proxmox web interface, typically at https://<your-server-ip>:8006.
2. In the left-hand tree, expand your node and click local storage.
3. Select the ISO Images tab in the content panel, then click Upload.
4. Choose your ISO file (Windows, Ubuntu, Debian, etc.) and click Upload. Large ISOs may take a minute or two depending on your connection speed.
5. Once uploaded, the ISO appears in the list and is ready to attach to a new VM.

Create the VM: General Tab

1. Click the Create VM button in the top-right corner of the interface.
2. On the General tab, assign a VM ID — Proxmox auto-increments from 100, but you can choose any unused number.
3. Enter a descriptive Name such as win11-test or ubuntu-dev. This label appears in the node tree.
4. Leave Start at boot unchecked for now; you can enable it later once you’ve confirmed the VM works correctly.

OS Tab

1. Set Use CD/DVD disc image file (ISO) and select your uploaded ISO from the storage dropdown.
2. Set the Guest OS type — choose Microsoft Windows for Windows, or Linux for Linux distributions. This hints to Proxmox which default drivers to suggest.
3. Select the appropriate Version (e.g., 11/2022/2025 for Windows 11).

System Tab

1. For BIOS, choose OVMF (UEFI) for modern operating systems including Windows 11 (required). Use SeaBIOS only for legacy operating systems or older Linux distributions.
2. If using UEFI, tick Add EFI Disk and select a storage location — this stores the UEFI firmware variables.
3. For Windows 11 specifically, tick Add TPM and select v2.0. This satisfies the TPM 2.0 requirement. If you need to bypass the TPM check (for example when testing unsupported hardware configurations), you can add a registry workaround during Windows Setup, but using the virtual TPM is cleaner and Microsoft-compliant.
4. Set Machine to q35 for modern guests — it supports PCIe, is required for UEFI/TPM, and is the recommended default. Use i440fx only for very old operating systems that lack q35 support.
5. Set the SCSI Controller to VirtIO SCSI single for Linux guests. For Windows, you can start with LSI Logic SAS if you’d rather avoid loading extra drivers during setup, though VirtIO is significantly faster and worth the extra step.

Disks Tab

1. Select your Storage pool (e.g., local-lvm for LVM thin storage, or local for directory-based storage).
2. Set the Disk size — 64 GB is a sensible minimum for Windows 11; 32 GB is workable for most Linux servers.
3. For Format, raw gives the best performance with LVM; qcow2 is required if you want snapshot support on directory-based storage and supports thin provisioning.
4. Set the Bus/Device to VirtIO Block for Linux guests for maximum throughput. Windows guests need the VirtIO drivers ISO loaded as a second CD-ROM during installation before the disk is recognised — without it, Windows Setup will not see the drive.
5. Enable Discard (for SSD-backed storage) and IO thread for better performance on busy hosts.

CPU Tab

1. Set Sockets to 1 for most workloads.
2. Assign the number of Cores — 2 is adequate for a Linux server; 4 is recommended for a Windows 11 VM used for software testing.
3. Set Type to host to pass through the host CPU’s full instruction set. This improves performance and is necessary for some applications. Use kvm64 if you plan to migrate VMs between different CPU generations.

Memory Tab

1. Enter the Memory (MiB) value. Windows 11 requires a minimum of 4096 MiB (4 GB); 8192 MiB (8 GB) is more comfortable for UK business software testing scenarios where multiple applications run simultaneously.
2. Leave Ballooning enabled — it allows the host to reclaim unused RAM from the guest dynamically, which is useful on shared hosts.

Network Tab

1. Set the Bridge to vmbr0 (the default bridge that connects to your physical network interface).
2. Set the Model to VirtIO (paravirtualized) for Linux guests — it offers significantly higher throughput and lower CPU overhead than emulated NICs. Windows guests again need the VirtIO drivers ISO to use this; alternatively, use Intel E1000 for out-of-the-box compatibility during initial setup, then switch to VirtIO once drivers are installed.
3. Leave Firewall ticked unless you have a specific reason to bypass the Proxmox firewall rules.

Finish the Wizard and Start the VM

1. Review the Confirm tab — check the summary matches your intended configuration.
2. Leave Start after created unticked so you can make any last adjustments first.
3. Click Finish. The VM appears in the node tree.
4. Select the VM, go to the Hardware tab to add a second CD-ROM drive if you need to attach the VirtIO drivers ISO alongside your main installation ISO.
5. Click Start, then open the Console tab to interact with the VM. Use noVNC for browser-based access or SPICE for a richer desktop experience.

Enable QEMU Guest Agent

1. In the VM’s Options tab, double-click QEMU Guest Agent and tick Enabled.
2. Inside the guest OS, install the agent: on Ubuntu/Debian run sudo apt install qemu-guest-agent && sudo systemctl enable --now qemu-guest-agent; on Windows, install it via the VirtIO drivers ISO (the guest-agent folder).
3. Once active, the agent allows Proxmox to display the VM’s IP address in the summary panel, perform clean shutdowns from the UI, and take file-system-consistent snapshots.

Take a Snapshot Before Major Changes

1. With the VM running or stopped, click the Snapshots tab.
2. Click Take Snapshot, give it a descriptive name such as clean-install or pre-software-update, and optionally tick Include RAM to capture live memory state.
3. Click Take Snapshot to confirm. Snapshots are instantaneous on LVM-thin and qcow2 storage.
4. To roll back, select the snapshot and click Rollback. This is particularly valuable in UK business environments where staff test third-party or legacy software on Windows 11 VMs — if an installation goes wrong, you can restore the clean state in seconds rather than rebuilding the entire machine.

Basic VM Management

1. Start: Select the VM and click Start, or right-click the VM in the tree and choose Start.
2. Shutdown: Use Shutdown for a clean OS-level power-off (requires Guest Agent for best results), or Stop to force-cut power immediately.
3. Console access: Click the Console button to open the noVNC viewer in your browser — no additional client software required.
4. Clone a VM: Right-click any VM and choose Clone to create an identical copy, useful for spinning up multiple test environments quickly.
5. Resize a disk: Shut the VM down, go to Hardware, select the disk, and click Resize Disk — Proxmox will extend it, and you then expand the partition from within the guest OS.