Ceph integration topics at OpenStack PTG

ceph-{container,ansible} branching

Together with John Fulton and Guillaume Abrioux (and after PTG, Sebastien Han) we put some thought into how to make the Ceph container images and ceph-ansible releases fit better the OpenStack model; the container images and ceph-ansible are in fact loosely coupled (not all versions of the container images work with all versions of ceph-ansible) and we wanted to move from a "rolling release" into a "point release" approach, mainly to permit regular maintenance of the previous versions known to work with the previous OpenStack versions. The plan goes more or less as follows:

• ceph-{container,ansible} should be released together with the regular ceph updates
• ceph-container will start using tags and stable branches like ceph-ansible does

The changes for the ceph/daemon docker images are visible already: https://hub.docker.com/r/ceph/daemon/tags/

Multiple Ceph clusters

In the attempt to support better the "edge computing" use case, we discussed adding support for the deployment of multiple Ceph clusters in the overcloud.

Together with John Fulton and Steven Hardy (and after PTG, Gregory Charot) we realized this could be done using multiple stacks and by doing so, hopefully simplify managament of the "cells" and avoid potential issues due to orchestration of large clusters.

Much of this will build on Shardy's blueprint to split the control plane, see spec at: https://review.openstack.org/#/c/523459/

The multiple Ceph clusters specifics will be tracked via another blueprint: https://blueprints.launchpad.net/tripleo/+spec/deploy-multiple-ceph-clusters

ceph-ansible testing with TripleO

We had a very good chat with John Fulton, Guillaume Abrioux, Wesley Hayutin and Javier Pena on how to get tested new pull requests for ceph-ansible with TripleO; basically trigger an existing TripleO scenario on changes proposed to ceph-ansible.

Given ceph-ansible is hosted on github, Wesley's and Javier suggested this should be possible with Zuul v3 and volunteered to help; some of the complications are about building an RPM from uncommitted changes for testing.

Move ceph-ansible triggering from workflow_tasks to external_deploy_tasks

This is a requirement for the Rocky release; we want to migrate away from using workflow_tasks and use external_deploy_tasks instead, to integrate into the "config-download" mechanism.

This work is tracked via a blueprint and we have a WIP submission on review: https://blueprints.launchpad.net/tripleo/+spec/ceph-ansible-external-deploy-tasks

We're also working with Sofer Athlan-Guyot on the enablement of Ceph in the upgrade CI jobs and with Tom Barron on scenario004 to deploy Manila with Ganesha (and CephFS) instead of the CephFS native backend.

Hopefully I didn't forget much; to stay updated on the progress join #tripleo on freenode or check our integration squad status at: https://etherpad.openstack.org/p/tripleo-integration-squad-status