Docker is officially supported in RHEL/CentOS 7 in the extras repository: How is the docker container runtime supported in RHEL 7? - Red Hat Customer Portal
They provide two different packages,
docker (1.12.6) and
docker-latest (1.13.1): Introducing docker-latest for RHEL 7 and RHEL Atomic Host - Red Hat Customer Portal
As with everything included in the base distro, they are maintained by Red Hat and fixes are backported as necessary. Red Hat’s Docker packages are stable and used in production for their OpenShift Enterprise product.
However, the Discourse installer refuses to use them, since it does not know that they are Red Hat LTS version, which makes sense if you’re using the official Docker repository, but not with Red Hat’s packages. Installing the Docker 3rd party repository is unsupported by Red Hat, introduces an additional dependency and is and potentially less stable than using the Red Hat packages.
I can confirm that the Discourse cloud setup - with the version check commented out - works perfectly fine with CentOS 7.4 and
The Discourse installer should detect RHEL and do some basic RHEL-specific checks:
- we might want to check for ftype=0 on XFS, but it probably works fine even with ftype=0 set (many production OpenShift setups use ftype=0 without experiencing issues, as far as I know, it’s mostly about performance)
- either correct SELinux context set for Docker volumes or Docker configured without
--selinux-enabled(by default, Red Hat’s Docker version uses SELinux sVirt as an additional layer of security against container escapes - it can be turned off without disabling SELinux for the whole system)