Hello Stackers, As you may have seen, the TripleO project has been testing the idea of building container images using a simplified toolchain [0]. The idea is to build smaller, more easily maintained images to simplify the lives of TripleO consumers. Since TripleO's move to containers, the project has been leveraging Kolla to provide Dockerfiles, and while this has worked, TripleO has created considerable tooling to bend Kolla images to its needs. Sadly this has resulted in an image size explosion and the proliferation of difficult to maintain tools, with low bus factors, which are essential to the success of the project. To address the risk centered around the TripleO containerization story, we've drafted a spec [0], which we believe outlines a more sustainable future. In this specification, we've designed a new, much more straightforward, approach to building container images for the TripleO project. The "simple container generation," specification does not intend to be a general-purpose tool used to create images for the greater OpenStack community, both Loci and Kolla do that already. This effort is to build containers only for TripleO using distro provided repositories, with distro maintained tooling. By focusing only on what we need, we're able to remove all general-purpose assumptions and create a vertically integrated stack resulting in a much smaller surface area. To highlight how all this works, we've put together several POC changes: * Role and playbook to implement the Containerfile specification [1]. * Tripleoclient review to interface with the new role and playbook [2]. * Directory structure for variable file layout [3]. * To see how this works using the POC code, building images we've tested in real deployments, please watch the ASCII-cast [4]. * Example configuration file examples are here [5][6][7]. A few examples of size comparisons between our proposed tooling versus current Kolla based images [8]: - base: + Kolla: 588 MB - new: 211 MB # based on ubi8, smaller than centos8 - nova-base: + Kolla: 1.09 GB - new: 720 MB - nova-libvirt: + Kolla: 2.14 GB - new: 1.9 GB - keystone: + Kolla: 973 MB - new: 532 MB - memcached: + Kolla: 633 MB - new: 379 MB While the links shown are many, the actual volume of the proposed change is small, although the impact is massive: * With more straightforward to understand tools, we'll be able to get broader participation from the TripleO community to maintain our containerization efforts and extend our service capabilities. * With smaller images, the TripleO community will serve OpenStack deployers and operators better; less bandwidth consumption and faster install times. We're looking to chart a more reliable path forward, and making the TripleO user experience a great one. While the POC changes are feature-complete and functional, more work is needed to create the required variable files; however, should the proposed specification be ratified, we expect to make quick work of what's left. As such, if you would like to be involved or have any feedback on anything presented here, please don't hesitate to reach out. We aim to provide regular updates regarding our progress on the "Simple container generation" initiative, so stay tuned. Thanks, Kevin and Emilien [0] https://review.opendev.org/#/c/723665/ [1] https://review.opendev.org/#/c/722557/ [2] https://review.opendev.org/#/c/724147/ [3] https://review.opendev.org/#/c/722486/ [4] https://files.macchi.pro:8443/demo-container-images/ [5] http://paste.openstack.org/show/792995/ [6] http://paste.openstack.org/show/792994/ [7] http://paste.openstack.org/show/792993/ [8] https://4ce3fa2efa42bb6b3a69-771991cd07d409aaec3e4ca5eafdd7e0.ssl.cf2.rackcd... Kevin Carter IRC: kecarter