Docker for Mac vs. Docker Toolbox

Estimated reading time: 8 minutes

If you already have an installation of Docker Toolbox, read these topics first to learn how Docker for Mac and Docker Toolbox differ, and how they can coexist.

The Docker Toolbox environment

Docker Toolbox installs docker, docker-compose, and docker-machine in /usr/local/bin on your Mac. It also installs VirtualBox. At installation time, Toolbox uses docker-machine to provision a VirtualBox VM called default, running the boot2docker Linux distribution, with Docker Engine with certificates located on your Mac at $HOME/.docker/machine/machines/default.

Before you use docker or docker-compose on your Mac, you typically use the command eval $(docker-machine env default) to set environment variables so that docker or docker-compose know how to talk to Docker Engine running on VirtualBox.

This setup is shown in the following diagram.

Docker Toolbox Install

The Docker for Mac environment

Docker for Mac is a Mac native application, that you install in /Applications. At installation time, it creates symlinks in /usr/local/bin for docker and docker-compose and others, to the commands in the application bundle, in /Applications/Docker.app/Contents/Resources/bin.

Here are some key points to know about Docker for Mac before you get started:

  • Docker for Mac uses HyperKit instead of Virtual Box. Hyperkit is a lightweight macOS virtualization solution built on top of Hypervisor.framework in macOS 10.10 Yosemite and higher.

  • When you install Docker for Mac, machines created with Docker Machine are not affected.

  • Docker for Mac does not use docker-machine to provision its VM. The Docker Engine API is exposed on a socket available to the Mac host at /var/run/docker.sock. This is the default location Docker and Docker Compose clients use to connect to the Docker daemon, so you to use docker and docker-compose CLI commands on your Mac.

This setup is shown in the following diagram.

Docker for Mac Install

With Docker for Mac, you only get (and only usually need) one VM, managed by Docker for Mac. Docker for Mac automatically upgrades the Docker client and daemon when updates are available.

If you do need multiple VMs, such as when testing multi-node swarms, you can continue to use Docker Machine, which operates outside the scope of Docker for Mac. See Docker Toolbox and Docker for Mac coexistence.

Setting up to run Docker for Mac

  1. Check whether Toolbox DOCKER environment variables are set:

     $ env | grep DOCKER
     DOCKER_HOST=tcp://192.168.99.100:2376
     DOCKER_MACHINE_NAME=default
     DOCKER_TLS_VERIFY=1
     DOCKER_CERT_PATH=/Users/<your_username>/.docker/machine/machines/default
    

    If this command returns no output, you are ready to use Docker for Mac.

    If it returns output (as shown in the example), unset the DOCKER environment variables to make the client talk to the Docker for Mac Engine (next step).

  2. Run the unset command on the following DOCKER environment variables to unset them in the current shell.

     unset DOCKER_TLS_VERIFY
     unset DOCKER_CERT_PATH
     unset DOCKER_MACHINE_NAME
     unset DOCKER_HOST
    

Now, this command should return no output.

      $ env | grep DOCKER

If you are using a Bash shell, you can use unset ${!DOCKER_*} to unset all DOCKER environment variables at once. (This does not work in other shells such as zsh; you need to unset each variable individually.)

Note: If you have a shell script as part of your profile that sets these DOCKER environment variables automatically each time you open a command window, then you need to unset these each time you want to use Docker for Mac.

If you install Docker for Mac on a machine where Docker Toolbox is installed..

Docker for Mac replaces the docker and docker-compose command lines in /usr/local/bin with symlinks to its own versions.

See also Unset environment variables in the current shell in the Docker Machine topics.

Docker Toolbox and Docker for Mac coexistence

You can use Docker for Mac and Docker Toolbox together on the same machine. When you want to use Docker for Mac, make sure all DOCKER environment variables are unset. You can do this in bash with unset ${!DOCKER_*}. When you want to use one of the VirtualBox VMs you have set with docker-machine, just run a eval $(docker-machine env default) (or the name of the machine you want to target). This switches the current command shell to talk to the specified Toolbox machine.

This setup is represented in the following diagram.

Docker Toolbox and Docker for Mac coexistence

Using different versions of Docker tools

The coexistence setup works as is as long as your VirtualBox VMs provisioned with docker-machine run the same version of Docker Engine as Docker for Mac. If you need to use VMs running older versions of Docker Engine, you can use a tool like Docker Version Manager to manage several versions of docker client.

Checking component versions

Ideally, the Docker CLI client and Docker Engine should be the same version. Mismatches between client and server, and among host machines you might have created with Docker Machine can cause problems (client can’t talk to the server or host machines).

If you already have Docker Toolbox installed, and then install Docker for Mac, you might get a newer version of the Docker client. Run docker version in a command shell to see client and server versions. In this example, the client installed with Docker for Mac is Version: 1.11.1 and the server (which was installed earlier with Toolbox) is Version: 1.11.0.

$ docker version
Client:
Version:      1.11.1
...

Server:
Version:      1.11.0
...

Also, if you created machines with Docker Machine (installed with Toolbox) then upgraded or installed Docker for Mac, you might have machines running different versions of Engine. Run docker-machine ls to view version information for the machines you created. In this example, the DOCKER column shows that each machine is running a different version of server.

$ docker-machine ls
NAME             ACTIVE   DRIVER         STATE     URL                         SWARM   DOCKER    ERRORS
aws-sandbox      -        amazonec2      Running   tcp://52.90.113.128:2376            v1.10.0
default          *        virtualbox     Running   tcp://192.168.99.100:2376           v1.10.1
docker-sandbox   -        digitalocean   Running   tcp://104.131.43.236:2376           v1.10.0

You might also run into a similar situation with Docker Universal Control Plane (UCP).

There are a few ways to address this problem and keep using your older machines. One solution is to use a version manager like DVM.

Migrating from Docker Toolbox to Docker for Mac

Docker for Mac does not propose Toolbox image migration as part of its installer since version 18.01.0. You can migrate existing Docker Toolbox images with the scripts described below. (This migration cannot merge images from both Docker and Toolbox: any existing Docker image is replaced by the Toolbox images.)

Run the following shell commands in a terminal. You need a working qemu-img; it is part of the qemu package in both MacPorts and Brew:

$ brew install qemu  # or sudo port install qemu

First, find your Toolbox disk images. You probably have just one: ~/.docker/machine/machines/default/disk.vmdk.

$ vmdk=~/.docker/machine/machines/default/disk.vmdk
$ file "$vmdk"
/Users/akim/.docker/machine/machines/default/disk.vmdk: VMware4 disk image

Second, find out the location and format of the disk image used by your Docker for Mac.

$ settings=~/Library/Group\ Containers/group.com.docker/settings.json
$ dimg=$(sed -En 's/.*diskPath.*:.*"(.*)".*/\1/p' < "$settings")
$ echo "$dimg"
/Users/akim/Library/Containers/com.docker.docker/Data/vms/0/Docker.raw

In this case the format is raw (it could have been qcow2), and the location is ~/Library/Containers/com.docker.docker/Data/vms/0/.

Then:

  • if your format is qcow2, run
    $ qemu-img convert -p -f vmdk -O qcow2 -o lazy_refcounts=on "$vmdk" "$dimg"
    
  • if your format is raw, run the following command. If you are short on disk space, it is likely to fail.
    $ qemu-img convert -p -f vmdk -O raw "$vmdk" "$dimg"
    

Finally (optional), if you are done with Docker Toolbox, you may fully uninstall it.

How do I uninstall Docker Toolbox?

You might decide that you do not need Toolbox now that you have Docker for Mac, and want to uninstall it. For details on how to perform a clean uninstall of Toolbox on the Mac, see How to uninstall Toolbox in the Toolbox Mac topics.

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