Slow builds on Docker-CE on CentOS7

I have built out a set of 4 Docker workers and 3 Swarm managers. I also have setup a shared repository which uses NFS as the backend so it can run on any worker host. So far, so good. These are all fresh OS and Docker builds.

As I was making some custom builds I noticed that each step was taking around ~15 seconds. This includes simple ENV settings. Further troubleshooting is showing that all docker volume commands, and any other commands, that touch volumes seem to also be taking ~15s to run. This behavior is seen on all hosts.

I’ve dug through forums and Google to only find mentions of this slow behavior from back in 2016. As a test I had all nodes leave the swarm, stopped Docker and uninstalled it. I then wiped out all files under /var/lib/docker and reinstalled. So with just Docker-CE installed, I still have this lag and I’m unable to track the reason.

Can anyone point me in a direction where I can dig deeper, or just tell me likely problems to fix, so I can ensure the Docker nodes are ready to be used by devs?

Thanks