Devstack-gate is a collection of scripts used by the OpenStack CI team to test every change to core OpenStack projects by deploying OpenStack via devstack on a cloud server.
All changes to core OpenStack projects are “gated” on a set of tests so that it will not be merged into the main repository unless it passes all of the configured tests. Most projects require unit tests with pep8 and several versions of Python. Those tests are all run only on the project in question. The devstack gate test, however, is an integration test and ensures that a proposed change still enables several of the projects to work together. Any proposed change to the configured set of projects must pass the devstack gate test.
Obviously we test nova, glance, keystone, horizon, neutron and their clients because they all work closely together to form an OpenStack system. Changes to devstack itself are also required to pass this test so that we can be assured that devstack is always able to produce a system capable of testing the next change to nova. The devstack gate scripts themselves are included for the same reason.
The devstack test starts with an essentially bare virtual machine made available by Nodepool and prepares the testing environment. This is driven by the the devstack-gate repository which holds several scripts that are run by Jenkins.
When a proposed change is approved by the core reviewers, Jenkins triggers the devstack gate test itself. This job runs on one of the previously configured nodes and invokes the devstack-vm-gate-wrap.sh script which checks out code from all of the involved repositories, and merges the proposed change. That script then calls devstack-vm-gate.sh which installs a devstack configuration file, and invokes devstack. Once devstack is finished, it runs exercise.sh and Tempest, which perform integration testing. After everything is done, devstack-gate copies and formats all of the logs for archival. A jenkins jobs then copies these logs to the log archive.
Instructions for debugging a failure can be found in the Devstack-gate README