img-proof Documentation

img-proof (IPA) provides a command line utility to test images in the Public Cloud (AWS, Azure, GCE, OCI, Aliyun, etc.).


With img-proof you can now test custom images in a cloud framework agnostic way with one tool and one API. img-proof supports the Fedora, openSUSE, RHEL, and SLES distributions. It also supports the three largest cloud frameworks (AWS, Azure and GCE). However, it is intended to be distribution agnostic and framework transparent so both are easily extensible.


The goal of img-proof is to provide a unit test framework that can be used to verify the actual state of custom public cloud images. To do this it leverages two packages.


Tests are written using the pytest framework.

The pytest framework makes it easy to write small tests, yet scales to support complex functional testing for applications and libraries.


Testinfra is a plugin for pytest which provides connection backends and test modules such as File, Group, User, Package, Service, etc.

With Testinfra you can write unit tests in Python to test actual state of your servers configured by management tools like Salt, Ansible, Puppet, Chef and so on.


img-proof leverages Testinfra as a unit test framework. It also provides distribution classes and cloud framework classes.

Distribution Classes

Classes can be used to provide distribution specific testing. This includes tests such as soft reboot (e.g. “shutdown -r now”) and update.

The current supported distributions are:

  • Fedora (fedora)

  • openSUSE_Leap (opensuse_leap)

  • RHEL (rhel)

  • SLES (sles)

In addition to soft reboot, refresh and update there is a built in test for hard reboot (framework reboot).

These tests are “synchronization points”. The tests are built into each distribution as the commands can be slightly different.

By default pytest does not guarantee the order of tests. However, there are cases where this is ideal when testing images. For example you can run an update then do a reboot to ensure an instance starts properly.

A test suite such as [‘test_soft_reboot’, ‘test_sles’, ‘test_update’, ‘test_hard_reboot’, ‘test_sles_ec2’] will be broken into five pytest invocations:

Soft reboot, test_sles, update, hard reboot, test_sles_ec2

The order of tests is guaranteed and the results will be aggregated to determine the status of a test run. If a test fails it will be re-run up to the number of retries. The default is three times and this can be configured with the –retry-count option.

Cloud Framework Classes

The cloud framework classes contain methods necessary to interact with instances/images in a given cloud framework.

Some of the required methods for cloud framework classes include:

  • Launch instances

  • Terminate instances

  • Get instance status

  • Get instance info

  • Stop/Start/Reboot instances

The implementations are dependent on each CSP API and require the CSP credentials to perform the necessary operations.

The current supported CSPs are:

  • Azure

  • EC2

  • GCE

  • OCI

  • SSH

  • Aliyun

The SSH class is generic and can be used for any accessible instance that is running. There are no credentials required except the instance needs the proper SSH User and SSH Key configured for access.

The SSH class cannot be used to test hard reboot (framework reboot) or to launch/start/stop/terminate instances.


Contributions to img-proof are welcome and encouraged. See CONTRIBUTING for info on getting started.


Please submit issues and requests to Github.


Copyright (c) 2021 SUSE LLC.

Distributed under the terms of GPL-3.0+ license, see LICENSE for details.