Docker command can't connect to Docker daemon

Question

I want to make a move to Docker, so I\'ve just started to mess around with it. I\'ve installed Docker on a VirtualBox Ubuntu 15.10 (Wily Werewolf) installation and as sugges

Answer 1

Add the user to the docker group

• Add the docker group if it doesn't already exist:

  sudo groupadd docker

• Add the connected user "${USER}" to the docker group:

  sudo gpasswd -a ${USER} docker

• Restart the Docker daemon:

  sudo service docker restart

• Either do a newgrp docker or log out/in to activate the changes to groups.

Answer 2

I had the same problem. Been struggling for two days to solve it.

It only worked when I did:

1. According to Docker's Tutorial, you need to add the Docker key if not already added using:

   $ sudo wget -qO- https://get.docker.com/gpg | sudo apt-key add -

2. Then make sure you grant docker privileges to yourself using:

   $ sudo usermod -aG docker $USER

Hope this helps you too.

Answer 3

After installing docker on Ubuntu, I ran the following command:

sudo service docker start

Have you tried it?

Answer 4

For Ubuntu 16.04

Inside file /lib/systemd/system/docker.service change:

ExecStart=/usr/bin/dockerd fd://

with:

ExecStart=/usr/bin/dockerd -H tcp://0.0.0.0:2375

Inside file /etc/init.d/docker change:

DOCKER_OPTS=

with:

DOCKER_OPTS="-H tcp://0.0.0.0:2375"

and then restart your computer.

Answer 5

As docker binds to a unix socket which is owned by root while starting up, using 'sudo' along with the docker commands will work.

Answer 6

Had the same issue and what worked for me was:
Checking the ownership of /var/run/docker.sock

ls -l /var/run/docker.sock

If you're not the owner then change ownership with the command

sudo chown *your-username* /var/run/docker.sock

Then you can go ahead and try executing the docker commands hassle-free :D