I'm actually looking for a good container hosting OS right now. I remember hearing some stuff about CoreOS being deprecated or something, but I can't find anything concrete?!
Do you know what the situation is?
I also looked a bit at RancherOS today, which looked pretty cool, but it seems to use 10x the memory of CoreOS...
Fedora CoreOS is intended to eventually provide a suitable replacement for ContainerLinux.
Red Hat ships a variant of RHEL called RHEL CoreOS, but the only way to run it is as part of OpenShift (for instance via https://try.openshift.com) where it is the default OS for machines which are managed as part of the cluster, so it’s not a real ContainerLinux equivalent (which you can run individually).
If you're mainly just looking for something with Docker preinstalled VMWare's PhotonOS[0] may be an option. It's a stripped down CentOS/RHEL based distro that's targeted at being a container host. I believe they've said they'll also package other container runtimes in the future as the market shifts.
A quick look shows the ISO as ~4GB, which is a bit concerning though - CoreOS is around 450MB, and RancherOS only 135MB (although it's a bit difficult to compare, since they both download stuff during boot).
That's not the install size. From the documentation there are multiple install options ranging in size so they just decided to package it all in one. "Minimal" install is like 400-500 MB iirc.
Do you know what the situation is?
I also looked a bit at RancherOS today, which looked pretty cool, but it seems to use 10x the memory of CoreOS...