The Oracle Linux group is pushing forward hard and their latest news is that Instant Client RPMs for Oracle Linux are downloadable for Oracle Linux 7 and Oracle Linux 6 without needing a click-through. This means you can now more easily provision systems using an automated install process. Sergio's blog post has the announcement and steps to use the packages.
Our Instant Client 18.3 Dockerfile has also been updated. As you'd expect, 'docker build' now does the download and install of Instant Client. Since 18.3 is effectively the renamed 22.214.171.124, and you can connect to Oracle Database 11.2 or later (the same as with the Instant Client 12.2), using the new Dockerfile is an obvious win.