I have been geting prepped to build the OpenShift origin codebase on Centos 7.  I started from a fairly minimal VM which did not have docker or Development Tools installed.  Once I thought I had all the prerequisites, I kicked off the build and got

Cannot connect to the Docker daemon. Is the docker daemon running on this host?

This seems to be due to the fact that  the ayoung user does not have permissions to read/write on the domain socket.  /var/run/docker.sock

$ ls -la /var/run/docker.sock
srw-rw----. 1 root root 0 Aug 9 09:03 /var/run/docker.sock

Enough other stuff seems to discuss this as well.  How can we set up for non-root and non-sudo access to docker?

On my Fedora system, I have:

$ ls -la /var/run/docker.sock
srw-rw----. 1 root docker 0 Aug 7 09:01 /var/run/docker.sock

I set this up long enough ago that I do not remember if I was the one that did this, or if it was a configuration setup by some other package. The docker group has a pretty random ID:

$ getent group docker
docker:x:14372:ayoung

So I probably did that.

Back to the VM:

sudo groupadd docker
 sudo chown root:docker /var/run/docker.sock
 sudo usermod -aG docker ayoung

I exited out and logged back in:

$ groups
ayoung wheel docker

And it worked.  Will the socket stay that way?  Hmm.  After the build completes, I’ll reboot the VM and see what we have.

Yes it did.  Is there a better way to do this?  Let me know if you do.