With latest virtualenv release (20.24.0) and its bundled setuptools version, stable/victoria gates started to fail , because setuptools is not compatible with the pbr version (5.5.0) which is in victoria branch's upper constraint . pbr's next release (5.5.1) removed the failing code, this is why the change is only needed in stable/victoria. This patch caps virtualenv to <20.24.0 to fix stable/victoria's gate, and also caps tox for the 'inner' virtualenv, otherwise tox>4 would be installed, that would introduce failures (those failures are fixed in newer stable branches, but it would need several backports and 'outer' tox is capped <4 anyway, so no worth dealing with it here).  AttributeError: module 'setuptools.command.easy_install' has no attribute 'get_script_header' 
Glance is an OpenStack project that provides services and associated libraries to store, browse, share, distribute and manage bootable disk images, other data closely associated with initializing compute resources, and metadata definitions.
Use the following resources to learn more:
To learn how to use Glance's API, consult the documentation available online at:
For information on how to contribute to Glance, please see the contents of the CONTRIBUTING.rst in this repository.
Any new code must follow the development guidelines detailed in the HACKING.rst file, and pass all unit tests.
Further developer focused documentation is available at:
To learn how to deploy and configure OpenStack Glance, consult the documentation available online at:
In the unfortunate event that bugs are discovered, they should be reported to the appropriate bug tracker. You can raise bugs here:
To learn more about Glance's new features, optimizations, and changes between versions, consult the release notes online at:
During each design summit, we agree on what the whole community wants to focus on for the upcoming release. You can see image service plans:
For more information about the Glance project please see: