How to run Docker on Ubuntu 15.04?

Question

I followed the official instructions on how to install Docker on Ubuntu, added my account to the "docker" group and rebooted the computer, and I'm not able to run "docker" (not even as root) as I get the following error:

$ sudo docker info
FATA[0000] Get http:///var/run/docker.sock/v1.18/info: dial unix /var/run/docker.sock: no such file or directory. Are you trying to connect to a TLS-enabled daemon without TLS? 

However, I realized that if from another session I run "sudo docker -d", then Docker will work just fine, even without using "sudo".

What’s the best way to fix this? I guess this issue is related to the service script, but I'm surprised that I couldn't find instructions or even other people finding the same issue.

Answer 1

To make the Docker daemon run at boot on 15.04, you can run:

systemctl enable docker

I guess they will soon update the get.docker.com script when more people complain about this, see also https://github.com/docker/docker/issues/12002#issuecomment-106759295

You can also run systemctl is-enabled docker to see if it's currently enabled or not.

Answer 2

There is a similar issue (11989), which says:

It could be a problem related to docker daemon not automatically starting under certain Ubuntu versions (cat /etc/lsb-release). See #12002 for an example.

Is the daemon running?

sudo service docker status

Issue 12002 illustrates the issue even for Ubuntu 15.04:

I need to sudo service docker restart after every reboot
I'm having the same issue on Ubuntu 15.04.
After "sudo service docker restart" it starts working.