You are using Linux (Ubuntu 14.04) and trying to run Docker for the first time. You run
docker ps or
docker version and you see this message:
"Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?"
How do you fix this problem to get Docker to work?
Run this command:
cat /var/log/upstart/docker.log | grep -i docker | grep -i linux
If you see this: ' level=fatal msg="Your Linux kernel version 2.6.32-042stab116.2 is not supported for running docker. Please upgrade your kernel to 3.10.0 or newer."' then you need to upgrade the kernel of the Linux machine or move to a different server.
"It is strongly recommended that you run Docker on a modern release of your preferred Linux distribution. … Generally a 3.8 or later kernel is required…" (Page 27 of Docker Up & Running by Matthias & Kane, O'Reilly Press, 2015.) Docker's website as of 3/20/18 shows that kernel version 3.10 or higher is recommended.