Created 6 years ago
Maintained by roshi
a small helper script to download and boot cloud images locally
Members 2


testcloud is a small helper script to download and boot cloud/coreos VM images locally. Testcloud supports wide range of distributions, namely Fedora, Fedora CoreOS, CentOS, CentOS Stream, Red Hat Enterprise Linux, Debian and Ubuntu.

testcloud can run either in system mode or in constrained user session mode, which is useful for running testcloud and its VMs in unprivileged containers.


The following procedure should only be used to install testcloud on a production system. For developing purposes, you need a different kind of installation which is described in the Testcloud Development section below.

To use testcloud on a production system:

  1. Install the testcloud.

    $ sudo dnf install testcloud

  2. Add yourself to the testcloud group.

    $ sudo usermod -a -G testcloud $USER

  3. Restart your user session to update the group privileges, or use su - to get a login shell for that particular user where the group settings will be updated.

    $ su -i $USER

  4. Now, you are ready to use testcloud.

Using testcloud

Creating a new instance

To create a new instance, you will need to provide distribution and version you wish to use or the url of some cloud image in the qcow2 format. If you do not have an image location of your own, you can use the image from the Fedora Cloud download pages (https://alt.fedoraproject.org/cloud/).

To create a new instance with the cloud image, run:

$ testcloud create <url for qcow2 image> or <distro:version>

Some examples how to create an instance with distribution:version shortcut:

# Latest Fedora Release
$ testcloud create fedora
# Fedora Rawhide (latest Nightly Compose)
$ testcloud create fedora:rawhide
# CentOS Stream 8
$ testcloud create centos-stream:8
# Ubuntu Hirsute (21.04)
$ testcloud create ubuntu:hirsute
# Debian 11
$ testcloud create debian:11

Supported distributions with shortcuts are: Fedora, CentOS, CentOS Stream, Ubuntu, Debian, Alma, Rocky, and Oracle. For other distributions, you can provide link to basically any qcow2 image which has the cloud-init package included.

Testcloud supports also Vagrant .box files, in a limited manner and currently only for Fedora and CentOS.

testcloud will download the qcow2 image and save it in the /var/lib/testcloud/backingstores/<qcow2-filename>. It will use this image a backing store for the newly created instance in /var/tmp/instances/<instance-name>. When the image has been already downloaded, testcloud will use the previously download image to create the instance.

To create a new instance with the coreos image, run:

$ testcloud create fedora-coreos:<stream> or <url for qcow2 image>

You will be able to see the instance using the list command.

$ testcloud list

Alternatively, the instances can also be viewed and manipulated using the virt-manager tool.

Creating an instance with specific architecture

Instances can be created with a different architecture than the host architecture. You'll need to have a proper qemu binary installed for this to work (eg. qemu-system-aarch64-core for aarch64 on x86_64 on Fedora). Supported architectures in testcloud are: x86_64, aarch64, ppc64le, and s390x. Any combinations of these are supported.

Some examples:

# Fedora aarch64 on x86_64 (or any other)
$ testcloud create fedora --arch aarch64
# CentOS Stream x86_64 on aarch64 (or any other)
$ testcloud create centos-stream --arch x86_64
# Fedora Rawhide ppc64le on aarch64 (or any other)
$ testcloud create fedora:rawhide --arch ppc64le

Starting, stopping, and removing an instance

Instances can be started and stopped using the instance interface of the testcloud, too:

  1. List all instances to see the correct name of the instance:

    $ testcloud list

  2. Start the instance:

    $ testcloud start <instance-name>

  3. Stop the instance:

    $ testcloud stop <instance-name>

  4. Remove the instance:

    $ testcloud remove <instance-name>

Removing the instance only succeeds when the appropriate instance has been stopped before. However, you can use the -f option to force removing the instance.

Other instance operations

  1. Reboot the instance:

    $ testcloud reboot <instance-name>

  2. Remove non-existing libvirt VMs from testcloud:

    $ testcloud clean

Logging into the instance

When the cloud/coreos instance is created, testcloud will return its IP address that you can use to access the running instance via ssh. The default login name is cloud-user and the password is passw0rd. Testcloud will output info how you can connect to any of the Supported Distributions.

ssh cloud-user@<instance-IP>

The IP address of an instance is also shown when you list the instance using the testcloud list command. You can also control the instance using the virt-manager , GNOME Boxes or any other tool to manage libvirt VMs.

Available options to create an instance

There are several options (all optional) that can be used to create a new instance using testcloud.

-c, --connection QEMU_URI

You can specify uri to qemu you wish to use. For limited environments, you might wish to use qemu:///session. Remote connections other than qemu:///session and qemu:///system (like qemu+ssh,...) are known to be problematic.

--arch ARCH

To request a speciffic architecture for the guest. The default | is the architecture of the host system.

--ram RAM

To set the amount of RAM that will be available to the virtual machine (in MiB).

--vcpus VCPUS

To set the amount of VCPUS that will be available to the virtual machine.


This turns off the graphical display of the virtual machine.


To open a VNC connection at the :1 display of the instance.

-n, --name NAME

To specify a custom name for you instance.

--timeout TIMEOUT

A time (in seconds) to wait for boot to complete. Setting to 0 (default) will disable this functionality.

--disksize DISKSIZE

To set the disk size of the virtual machine (in GiB)


To provide disk number you want


To provide nic number you want

To specify a local directory to mount and mount target like <host path>:<guest path>

There are several additional options that can be used to create a new Coreos instance using testcloud.

--bu_file BU_FILE

To provide a bu_file you want to use

--ign_file IGN_FILE

To provide an ign_file you want to use


To provide ssh pubkey path


The default configuration should work for many people but those defaults can be overridden through the use of a settings.py file containing the values to use when overriding default settings. The example file in conf/settings-example.py shows the possible configuration values which can be changed.

Note that in order for those new values to be picked up, the filename must be settings.py and that file must live in one of the following locations:

  • conf/settings.py in the git checkout
  • ~/.config/testcloud/settings.py
  • /etc/testcloud/settings.py

For example, if you wanted to set up an ssh accessible root account that uses an ssh key as the authentification method, you could provide the following to the ~/.config/testcloud/settings.py:

USER_DATA = """#cloud-config
    - default
    - name: root
      password: %s
      chpasswd: { expire: False }
      - <my ssh pub key>

Testcloud Development

To develop testcloud, you need to perform a more complicated process to install all its dependencies, download the source code and perform a set-up.

To install testcloud for development purposes:


  1. Install the dependencies for testcloud.

    $ sudo dnf install libvirt python3-libvirt libguestfs libguestfs-tools python3-requests python3-jinja2

  2. Start libvirtd.

    $ sudo systemctl start libvirtd

  3. Add the testcloud group to the system.

    $ sudo groupadd testcloud

  4. Add a user into the testcloud group.

    $ sudo usermod -a -G testcloud $USER

  5. Log out of the system and log in again to update the group information on your user or use a login shell on a different terminal.

    $ su - $USER


  1. Clone the testcloud repository.

    $ git clone https://pagure.io/testcloud.git

  2. Create the application directories.

    $ sudo mkdir -p -m 775 /var/lib/testcloud

    $ sudo mkdir -p -m 775 /var/lib/testcloud/instances

    $ sudo mkdir -p -m 775 /var/lib/testcloud/backingstores

  3. Change ownership on these directories to enable their use with testcloud.

    $ sudo chown qemu:testcloud /var/lib/testcloud

    $ sudo chown qemu:testcloud /var/lib/testcloud/instances

    $ sudo chown qemu:testcloud /var/lib/testcloud/backingstores

  4. Copy the .rules file to the polkit rules.

    $ sudo cp conf/99-testcloud-nonroot-libvirt-access.rules /etc/polkit-1/rules.d/

Running testcloud

  1. Navigate to your testcloud git repository.

    $ cd testcloud

  2. Execute the run_testcloud.py script to run the testcloud. You can use any options as with the regular installation, for example:

    $ ./run_testcloud.py instance create ...

  3. Alternatively, you can use pip to install testcloud onto the system and then use it like it has been installed normally.

    $ pip3 install -e . --user


There is a small testsuite you can run with:


This is a good place to contribute if you\'re looking to help out.

Issue Tracking and Roadmap

Our project tracker is on the Fedora QA-devel Pagure instance.


Thanks to Oddshocks for the koji downloader code :)


This code is licensed GPLv2+. See the LICENSE file for details.