Docker minimum kernel version 3.8.13 or 3.10

Question

On the Docker website I am seeing information that is close to being in conflict.

The page: https://docs.docker.com/installation/oracle/ Says "Docker requires the use of the Unbreakable Enterprise Kernel Release 3 (3.8.13) or higher on Oracle Linux."

The page: https://docs.docker.com/installation/binaries/ Says 3.10 is required.

I'm guessing that stuff got added into a special build of 3.8.13 which would otherwise require version 3.10.

If anybody could give some clarification that would be great.

Answer 1

Correct; in general, kernel 3.10 is the absolute minimum kernel version that supports the features that Docker requires to run stable (newer versions are preferred though).

However, some Linux distro's back-port features to older kernels so that they are still able to run Docker. Red Hat Enterprise Linux 6.5, for example, is able to run Docker on a kernel 2.6 (it's still a 12 year old kernel, though....)

To summarise;

• Always run the most up-to-date kernel version provided by your distribution
• Replacing the kernel that's provided by your distribution with a custom kernel might work, but is not officially supported.
• Some (cloud) providers replace the kernel with a customised version; this has been the cause of some issues.
• If you're building your own kernel, use a recent version (docker does take advantage of some features in recent versions)

There's also a shell-script to check if your system has the required dependencies in place and to check which features are available;

https://github.com/docker/docker/blob/master/contrib/check-config.sh

Update

Starting with Docker 1.8.0, Red Hat Enterprise Linux 6, and CentOS 6 (and Kernel 2.6) are no longer supported platforms for running Docker, and no new packages are released for those distributions. Running Docker on those platforms is highly discouraged, as the latest version released for RHEL 6 / CentOS 6 is Docker 1.7.1. It's recommended to upgrade your system to RHEL 7 / CentOS 7, which is actively supported.