README.rst

How to setup docker on OS X using boot2docker

Basic install

1. Install Virtualbox
2. Install XCode and the Command Line Tools

3. Install homebrew:

   ruby -e "$(curl -fsSL https://raw.github.com/Homebrew/homebrew/go/install)"

4. Install boot2docker:

   brew install boot2docker

5. Bootstrap boot2docker:

   boot2docker init
   boot2docker up

6. Add the DOCKER_HOST to your profile:

   echo "export DOCKER_HOST=tcp://$(boot2docker ip 2> /dev/null):2375" >> ~/.bashrc

Setup DNS

We will name the VM localdocker, allowing us to always be able to access the running containers on whatever port they are exposed.

Update your /etc/hosts file:

echo "$(boot2docker ip 2> /dev/null) localdocker" | sudo tee --append /etc/hosts

Now when a container is run:

docker run -p 5000:80 nginx

We can connect to the container via http://localdocker:5000/.

Bind mounting from OS X into docker containers

1. Download the boot2docker iso with Virtualbox Guest Additions:

   boot2docker down
   curl http://static.dockerfiles.io/boot2docker-v1.2.0-virtualbox-guest-additions-v4.3.14.iso > ~/.boot2docker/boot2docker.iso

2. Mount /Users into the VM in order to support binding volumes into docker containers:

   VBoxManage sharedfolder add boot2docker-vm -name home -hostpath /Users

3. Start boot2docker:

   boot2docker up

Install nsenter for inspecting containers

An appropriate way to inspect a running container is via nsenter. It can drop us into a shell inside of the container's filesystem and inspect its running processes. Unfortunately it only works on linux, so we will create a docker-enter script that works for us over ssh.

1. Build and install nsenter. You can run this from the host because the bind-mounting is still only from the VM:

   docker run --rm -v /var/lib/boot2docker:/target jpetazzo/nsenter

2. Setup docker-enter script for easy inspection in OS X:

   cat > /usr/local/bin/docker-enter <<'EOF'
   #!/bin/bash
   set -e
   
   # Check for nsenter. If not found, install it
   boot2docker ssh '[ -f /var/lib/boot2docker/nsenter ] || docker run --rm -v /var/lib/boot2docker/:/target jpetazzo/nsenter'
   
   # Use bash if no command is specified
   args=$@
   if [[ $# = 1 ]]; then
       args+=(/bin/bash)
   fi
   
   boot2docker ssh -t sudo /var/lib/boot2docker/docker-enter "${args[@]}"
   EOF
   
   chmod +x /usr/local/bin/docker-enter