Openstack,  TripleO

Scaling-up TripleO CI coverage with scenarios

TripleO CI up to eleven!



When the project OpenStack started, it was “just” a set of services with the goal to spawn a VM. I remember you run everything on your laptop and test things really quickly.
The project has now grown, and thousands of features have been implemented, more backends / drivers are supported and new projects joined the party.
It makes testing very challenging because everything can’t be tested in CI environment.

TripleO aims to be an OpenStack installer, that takes care of services deployment. Our CI was only testing a set of services and a few plugins/drivers.
We had to find a way to test more services, more plugins, more drivers, in a efficient way, and without wasting CI resources.

So we thought that we could create some scenarios with a limited set of services, configured with a specific backend / plugin, and one CI job would deploy and test one scenario.
Example: scenario001 would be the Telemetry scenario, testing required services like Keystone, Nova, Glance, Neutron, but also Aodh, Ceilometer and Gnocchi.

Puppet OpenStack CI is using this model for a while and it works pretty well. We’re going to reproduce it into TripleO CI to have consistency.


How scenarios are run when patching TripleO?

We are using a feature in Zuul that allows to select which scenario we want to test, depending on the files we try to patch in a commit.
For example, if I submit a patch in TripleO Heat Templates and I try to modify “puppet/service/ceilometer-api.yaml” which is the composable service for Ceilometer-API, Zuul will trigger scenario001. See Zuul layout:

- name : ^gate-tripleo-ci-centos-7-scenario001-multinode.*$
    - ^puppet/services/aodh.*$
    - ^manifests/profile/base/aodh.*$
    - ^puppet/services/ceilometer.*$
    - ^manifests/profile/base/ceilometer.*$
    - ^puppet/services/gnocchi.*$
    - ^manifests/profile/base/gnocchi.*$


How can I bring my own service in a scenario?

The first step is to look at Puppet CI matrix and see if we already test the service in a scenario. If yes, please keep this number consistent with TripleO CI matrix. If not, you’ll need to pick a scenario, usually the less loaded to avoid performances issues.
Now you need to patch openstack-infra/project-config and specify the files that are deploying your service.
For example, if your service is “Zaqar”, you’ll add something like:

- name : ^gate-tripleo-ci-centos-7-scenario002-multinode.*$
    - ^puppet/services/zaqar.*$
    - ^manifests/profile/base/zaqar.*$

Everytime you’ll send a patch to TripleO Heat Templates in puppet/services/zaqar* files or in puppet-tripleo manifests/profile/base/zaqar*, scenario002 will be triggered.

Finally, you need to send a patch to openstack-infra/tripleo-ci:

  • Modify to add the new service in the matrix.
  • Modify templates/scenario00X-multinode-pingtest.yaml and add a resource to test the service (in Zaqar, it could be a Zaqar Queue).
  • Modify test-environments/scenario00X-multinode.yaml and add the TripleO composable services and parameters to deploy the service.

Once you send the tripleo-ci patch, you can block it with -1 workflow to avoid accidental merge. Now go on openstack/tripleo-heat-templates and try to modify zaqar composable service by adding a comment or something you actually want to test. In the commit message, add “Depends-On: XXX” where XXX is the commit ID of the tripleo-ci patch. When you’ll send the patch, you’ll see that Zuul will trigger the appropriate scenario and your service will be tested.



What’s next?

  • Allow to extend testing outside pingtest. Some services, for example Ironic, can’t be tested with pingtest. Maybe run Tempest for a set of services would be something to investigate.
  • Zuul v3 is the big thing we’re all waiting to extend the granularity of our matrix. A current limitation current Zuul version (2.5) is that we can’t run scenarios in Puppet OpenStack modules CI because we don’t have a way combine both files rules that we saw before AND running the jobs for a specific project without files restrictions (ex: puppet-zaqar for scenario002). In other words, our CI will be better with Zuul v3 and we’ll improve our testing coverage by running the right scenarios on the right projects.
  • Extend the number of nodes. We currently use multinode jobs which deploy an undercloud and a subnode for overcloud (all-in-one). Some use-cases might require a third node (example with Ironic).

Any feedback on this blog post is highly welcome, please let me know if you want me to cover something more in details.

Software Engineeer at Red Hat, Private Pilot, French guy hiding somewhere in Canada.