Docker CE Overlay2

Question

I am looking for clarity regarding using Docker CE on RHEL, and the stipulations of the Overlay vs Overlay2 file system.

From Docker Docs I see the following quotes:

Note: If you use OverlayFS, use the overlay2 driver rather than the overlay driver, because it is more efficient in terms of inode utilization. To use the new driver, you need version 4.0 or higher of the Linux kernel.

And...

The overlay2 driver is supported for Docker EE and recommended for Docker CE.

And...

Note: If you use OverlayFS, use the overlay2 driver rather than the overlay driver, because it is more efficient in terms of inode utilization. To use the new driver, you need version 4.0 or higher of the Linux kernel, unless you are a Docker EE user on RHEL or CentOS, in which case you need version 3.10.0-693 or higher of the kernel and to follow some extra steps.

The AWS AMI I use is RHEL and from docker info I see I have:

Server Version: 17.09.0-ce

Storage Driver: overlay

Kernel Version: 3.10.0-693.11.6.el7.x86_64

Is there a path forward to using Overlay2 FS, or must I either upgrade the kernel to 4.0 or use Docker EE?

Answer 1

RHEL's kernel 3.10.0-693 do support overlay2 and Docker CE can use them just as well as Docker EE as the moby component of Docker EE and Docker CE are essentially the same.

The lack of support for CE here mostly just means the level of prioritization of features and bug fixes if you have problems when using overlay2 but don't own an EE license. When a CE user encounters problems/bugs with unsupported configurations, fixing it will be considered a low priority, so those issues are unlikely to ever be fixed unless it affects other EE users.