Shared Volume in Docker through Vagrant

Question

I have a Vagrant virtualbox which hosts a Docker container. The host machine has a folder which needs to be accessible in the vm and the container:

Host: /host/path => VM: /vagrant/path => Container: /docker/path

Background: /host/path/ holds the development files for a project which are available at container level to ensure automatic reloads when a change was made.

Configuration

Vagrant:

Vagrant.configure("2") do |config|
  config.vm.synced_folder "/host/path", "/vagrant/path"
end

Docker:

docker run -name mycontainer -d -v /vagrant/path:/docker/path my/image

Problem

This configuration works until i reload the vm. For example, when i restart my computer and start the vm with vagrant up, the docker container only recognizes an empty folder in /docker/path. I guess that could be some timing or sequencing issue. /vagrant/path is not empty and has the correct content.

My workaround at the moment is to reload the container after each restart of the vm:

docker rm mycontainer 
docker kill mycontainer 
docker run -name mycontainer -d -v /vagrant/path:/docker/path my/image

That feels wrong. Any ideas?

Answer 1

I had the same issues. The posted solutions didn't fit my requirements.

Here is my solution. If you run more than one container iterate over the cids in /var/lib/vagrant/cids/

The first script disables the docker-deamon container autostart at boot. The second script starts the container by its CID only if it isn't running.

This is working for the initial vagrant up and following vagrant [ up | reload ] --provision

# -*- mode: ruby -*-
# vi: set ft=ruby :

$disableAutostart = <<SCRIPT
if [ -e /home/vagrant/docker_autostart_disabled ]
then
  echo "Docker Container autostart already disabled ... "
else
  echo "Disable Docker Container autostart ..."
  echo "DOCKER_OPTS=\"-r=false ${DOCKER_OPTS}\"" > /etc/default/docker
  touch /home/vagrant/docker_autostart_disabled
fi
SCRIPT

$startContainer = <<SCRIPT
CID_FILE_PATH=/var/lib/vagrant/cids/
CID_FILE=$CID_FILE_PATH$(ls $CID_FILE_PATH)
if [ -e $CIDFILE ]
then
  CID=$(cat $CID_FILE)
  if ! $(docker inspect --format "{{.State.Running}}" $CID) 
    then
      echo "Starting Container ..."
      docker start $CID > /dev/null
    else
      echo "Docker Container already running ..."
  fi
else
  echo "No Container to start ... maybe something went wrong ..."
  echo "Keep calm and try vagrant destroy && vagrant up"
fi
SCRIPT

# Vagrantfile API/syntax version. Don't touch unless you know what you're doing!
VAGRANTFILE_API_VERSION = "2"

Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|

... VM cfg Stuff ...

  #Disable Docker autostart container
  config.vm.provision "shell" ,
   inline: $disableAutostart

  config.vm.provision :docker,
     version: "1.0.0"  do |d|
     d.build_image "/container/pseudo",
         args:"-t cdh5/pseudo-base"

     ... more container

     d.run "cdh5/data",
        auto_assign_name: false,
        args:"-v /vagrant/share:/home/student/share -h cdh5-single-node"
  end

      config.vm.provision :shell ,
        inline:  $startContainer,
        run:  "always"

end