[macos] Brew install docker does not include docker engine?

The following steps work fine on macOS Sierra 10.12.4. Note that after brew installs Docker, the docker command (symbolic link) is not available at /usr/local/bin. Running the Docker app for the first time creates this symbolic link. See the detailed steps below.

1. Install Docker.

   brew cask install docker
   

2. Launch Docker.

   • Press ? + Space to bring up Spotlight Search and enter Docker to launch Docker.
   • In the Docker needs privileged access dialog box, click OK.
   • Enter password and click OK.

   When Docker is launched in this manner, a Docker whale icon appears in the status menu. As soon as the whale icon appears, the symbolic links for docker, docker-compose, docker-credential-osxkeychain and docker-machine are created in /usr/local/bin.

   $ ls -l /usr/local/bin/docker*
   lrwxr-xr-x  1 susam  domain Users  67 Apr 12 14:14 /usr/local/bin/docker -> /Users/susam/Library/Group Containers/group.com.docker/bin/docker
   lrwxr-xr-x  1 susam  domain Users  75 Apr 12 14:14 /usr/local/bin/docker-compose -> /Users/susam/Library/Group Containers/group.com.docker/bin/docker-compose
   lrwxr-xr-x  1 susam  domain Users  90 Apr 12 14:14 /usr/local/bin/docker-credential-osxkeychain -> /Users/susam/Library/Group Containers/group.com.docker/bin/docker-credential-osxkeychain
   lrwxr-xr-x  1 susam  domain Users  75 Apr 12 14:14 /usr/local/bin/docker-machine -> /Users/susam/Library/Group Containers/group.com.docker/bin/docker-machine
   

3. Click on the docker whale icon in the status menu and wait for it to show Docker is running.

   

4. Test that docker works fine.

   $ docker run hello-world
   Unable to find image 'hello-world:latest' locally
   latest: Pulling from library/hello-world
   78445dd45222: Pull complete
   Digest: sha256:c5515758d4c5e1e838e9cd307f6c6a0d620b5e07e6f927b07d05f6d12a1ac8d7
   Status: Downloaded newer image for hello-world:latest
   
   Hello from Docker!
   This message shows that your installation appears to be working correctly.
   
   To generate this message, Docker took the following steps:
    1. The Docker client contacted the Docker daemon.
    2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
    3. The Docker daemon created a new container from that image which runs the
       executable that produces the output you are currently reading.
    4. The Docker daemon streamed that output to the Docker client, which sent it
       to your terminal.
   
   To try something more ambitious, you can run an Ubuntu container with:
    $ docker run -it ubuntu bash
   
   Share images, automate workflows, and more with a free Docker ID:
    https://cloud.docker.com/
   
   For more examples and ideas, visit:
    https://docs.docker.com/engine/userguide/
   
   $ docker version
   Client:
    Version:      17.03.1-ce
    API version:  1.27
    Go version:   go1.7.5
    Git commit:   c6d412e
    Built:        Tue Mar 28 00:40:02 2017
    OS/Arch:      darwin/amd64
   
   Server:
    Version:      17.03.1-ce
    API version:  1.27 (minimum version 1.12)
    Go version:   go1.7.5
    Git commit:   c6d412e
    Built:        Fri Mar 24 00:00:50 2017
    OS/Arch:      linux/amd64
    Experimental: true
   

5. If you are going to use docker-machine to create virtual machines, install VirtualBox.

   brew cask install virtualbox
   

   Note that if VirtualBox is not installed, then docker-machine fails with the following error.

   $ docker-machine create manager
   Running pre-create checks...
   Error with pre-create check: "VBoxManage not found. Make sure VirtualBox is installed and VBoxManage is in the path"