Anyway, we introduced support for Linux containers a year ago, back with Oracle Linux 6 and the release of UEKr3, no need to wait for OL7 (or rhel7...) we 've been doing this for almost a year and it was possible without having to reinstall servers and go from 6 to 7 and to systemd and have major changes. Just simply updating an OL6 environment and a reboot into uek3 and you were good to go, a year ago. So... with containers (and docker is very similar here)... you run one kernel. As opposed to running VMs where each VM is a completely isolated virtual environment with their own kernel and you can live migrate the VMs to another host if you need to update/patch the host, etc... So you run an OS that supports containers, you deploy your apps and isolate them nicely in a container each... and now you need to apply kernel security updates... well... that means, the host kernel on which all these containers environments are running... oops. my reboot now brings down a ton of containers. Well, not with ksplice. You run uptrack-update in the main environment and it nicely, online, without affecting your running apps in their containers or docker environments, updates to the latest fixes and CVEs. Done. No downtime, no scheduling issues with your application users... all set.
Supported.. since a year ago. Stable.