Contabo Custom Image (2026): Supported Formats, Requirements and How to Install One

Affiliate disclosure - This article contains Contabo affiliate links. If you order a VPS via our links, we earn a commission at no extra cost to you. Everything below about custom images comes from four articles in Contabo's help centre, read on 16 October 2026.

Short answer: Contabo accepts ISO and QCOW2 custom images, and checks the actual content of the file, not its extension. The image must be x86-64 (amd64) and support VirtIO drivers (virtio_scsi for the disk, virtio_net for the network). A QCOW2 can be compressed inside the file, but not wrapped in an archive like .qcow2.gz. Windows custom images are not allowed. And you need the Custom Images add-on, ordered in the Customer Panel.

ISO or QCOW2: which one to upload

Use an ISO when you want to run an installer yourself (through the server console), for example for a distribution Contabo does not offer. Use a QCOW2 when you have already prepared a system with your software, configuration and hardening, and want every new server to start from that exact state.

The requirements, from Contabo's help centre

• Formats: ISO and QCOW2 only. The system checks that the file really is one or the other; the extension alone does not count.
• Architecture: x86-64, also called amd64.
• Drivers: VirtIO support, meaning virtio_scsi for the hard disk and virtio_net for the network. Without them, the system will not see its disk or its network card.
• Windows: not allowed as a custom image, because of Contabo's licence agreement with Microsoft. Contabo also says its technical support will not help with a server running a custom Windows image.
• Who builds the image: you do. Contabo does not provide or build custom images.
• The add-on: custom images require the Custom Images add-on. If your server was bought without it, Contabo says to contact support.

An opened hard drive: a QCOW2 image is, in Contabo's words, a bootable copy of a disk like this one, with the system already installed.

Preparing a QCOW2 that Contabo accepts

Two standard qemu-img commands cover the format checks:

# Check what the file really is (Contabo checks the content, not the name)
qemu-img info my-image.qcow2

# Convert a raw disk image to QCOW2 with internal compression
qemu-img convert -c -O qcow2 my-disk.raw my-image.qcow2

The -c option compresses the QCOW2 internally, which Contabo allows; do not gzip the result afterwards. On Linux, check before exporting that the kernel of the image has the VirtIO modules Contabo requires, for example with lsmod | grep virtio on a running copy of the system.

Uploading and installing, step by step

These are the steps in Contabo's help centre:

1. Activate the add-on: in the Customer Panel, open Images, click Order Custom Image, review the price shown and click Order and Pay.
2. Upload the image: in Images, click Add Custom Image, fill in the mandatory fields, add a description if you want, and click Upload. You are notified when the upload is complete.
3. Install it: open Servers & Hosting, select VPS/VDS, open the server, choose Images in the menu, find your custom image and, in its Quick Action menu, select Install on this instance. Follow the prompts.

Custom images work on Contabo's Cloud VPS and on its VDS. If you only need a common Linux distribution for a VPN server, you do not need a custom image at all: the standard images are enough, and our WireGuard on Contabo guide starts from one.

See the current Contabo Cloud VPS plans

When a custom image is worth it

• You need an operating system Contabo does not offer. Upload its installer ISO.
• You rebuild servers often and want them identical. Prepare one QCOW2 with your configuration and install it on each new server.
• You want a hardened base for a VPN or a firewall appliance. Build and test it once locally, then deploy the same QCOW2.

For a single server running a mainstream distribution, the standard images are simpler and avoid the add-on. Comparing hosts before you commit? See Contabo alternatives by reason for leaving.

Summary

Contabo custom images come in two formats, ISO for installers and QCOW2 for ready-made disks, checked by content. They must be x86-64 with VirtIO drivers, cannot be Windows, may be compressed only inside the QCOW2 file, and require the Custom Images add-on. Upload under Images, then install from the server's Images menu.