Docker can't connect to docker daemon

Linux

The Post-installation steps for Linux documentation reveals the following steps:

1. Create the docker group.

   sudo groupadd docker

2. Add the user to the docker group.

   sudo usermod -aG docker $(whoami)

3. Log out and log back in to ensure docker runs with correct permissions.
4. Start docker.

   sudo service docker start

Mac OS X

As Dayel Ostraco says is necessary to add environments variables:

docker-machine start # Start virtual machine for dockerdocker-machine env  # It's helps to get environment variableseval "$(docker-machine env default)" # Set environment variables

The docker-machine start command outputs the comments to guide the process.

Linux

To run docker daemon on Linux (from CLI), run:

$ sudo service docker start # Ubuntu/Debian

^{Note: Skip the $ character when copy and pasting.}

On RedHat/CentOS, run: sudo systemctl start docker.

To initialize the "base" filesystem, run:

$ sudo service docker stop$ sudo rm -rf /var/lib/docker$ sudo service docker start

or manually like:

$ sudo docker -d --storage-opt dm.basesize=20G

Install docker-machine on Linux

To install machine binaries on Linux:

• locally:

  install -vm755 <(curl -L https://github.com/docker/machine/releases/download/v0.5.3/docker-machine_linux-amd64) $HOME/bin/docker-machine

• global:

  sudo bash -c 'install -vm755 <(curl -L https://github.com/docker/machine/releases/download/v0.5.3/docker-machine_linux-amd64) /usr/local/bin/docker-machine'

macOS

On macOS the docker binary is only a client and you cannot use it to run the docker daemon, because Docker daemon uses Linux-specific kernel features, therefore you can’t run Docker natively in OS X. So you have to install docker-machine in order to create VM and attach to it.

Install docker-machine on macOS

If you don't have docker-machine command yet, install it by using one of the following methods:

• Using Brew command: brew install docker-machine docker.

• manually from GitHub:

  install -v <(curl https://github.com/docker/machine/releases/download/v0.5.3/docker-machine_linux-amd64) /usr/local/bin/docker-machine

See: Get started with Docker for Mac.

Configure docker-machine on macOS

To start Docker Machine via Homebrew, run:

brew services start docker-machine

To create a default machine (if you don't have one, see: docker-machine ls):

docker-machine create --driver virtualbox default

Then set-up the environment for the Docker client:

eval "$(docker-machine env default)"

Then double-check by listing containers:

docker ps

See: Get started with Docker Machine and a local VM.

Install Docker.app on macOS

Alternatively to above solution, you can install a Docker app by:

brew cask install docker

Check this post for more details. See also: Cannot connect to the Docker daemon on macOS

If you are running Docker on OS X, running the following eval has worked for me.

eval "$(docker-machine env default)"

If you'd prefer not to have to run this eval statement on every terminal session, you can add this to your bash_profile:

#Dockereval "$(docker-machine env default)"

Be sure to restart the terminal session or run source on bash_profile for the changes to take effect.