The Vagrant Docker provisioner can automatically install Docker, pull Docker containers, and configure certain containers to run on boot.
The docker provisioner is ideal for organizations that are using Docker as a means to distribute things like their application or services. Or, if you are just getting started with Docker, the Docker provisioner provides the easiest possible way to begin using Docker since the provisioner automates installing Docker for you.
As with all provisioners, the Docker provisioner can be used along with all the other provisioners Vagrant has in order to setup your working environment the best way possible. For example, perhaps you use Puppet to install services like databases or web servers but use Docker to house your application runtime. You can use the Puppet provisioner along with the Docker provisioner.
Note: This documentation is for the Docker provisioner. If you are looking for the Docker provider, visit the Docker provider documentation.
The docker provisioner takes various options. None are required. If no options are required, the Docker provisioner will only install Docker for you (if it is not already installed).
images(array) - A list of images to pull using
docker pull. You can also use the
pull_imagesfunction. See the example below this section for more information.
In addition to the options that can be set, various functions are available and can be called to configure other aspects of the Docker provisioner. Most of these functions have examples in more detailed sections below.
build_image- Build an image from a Dockerfile.
pull_images- Pull the given images. This does not start these images.
run- Run a container and configure it to start on boot. This can only be specified once.
The provisioner can automatically build images. Images are built prior to any configured containers to run, so you can build an image before running it. Building an image is easy:
Vagrant.configure("2") do |config| config.vm.provision "docker" do |d| d.build_image "/vagrant/app" end end
The argument to build an image is the path to give to
docker build. This
must be a path that exists within the guest machine. If you need to get data
to the guest machine, use a synced folder.
build_image function accepts options as a second parameter. Here
are the available options:
args(string) - Additional arguments to pass to
docker build. Use this to pass in things like
-t "foo"to tag the image.
The docker provisioner can automatically pull images from the
Docker registry for you. There are two ways to specify images to
pull. The first is as an array using
Vagrant.configure("2") do |config| config.vm.provision "docker", images: ["ubuntu"] end
This will cause Vagrant to pull the "ubuntu" image from the registry for you automatically.
The second way to pull images is to use the
Each call to
pull_images will append the images to be pulled. The
images variable, on the other hand, can only be used once.
pull_images function cannot be used with the
simple configuration method for provisioners (specifying it all in one line).
Vagrant.configure("2") do |config| config.vm.provision "docker" do |d| d.pull_images "ubuntu" d.pull_images "vagrant" end end
In addition to pulling images, the Docker provisioner can run and start
containers for you. This lets you automatically start services as part of
Running containers can only be configured using the Ruby block syntax with
do...end blocks. An example of running a container is shown below:
Vagrant.configure("2") do |config| config.vm.provision "docker" do |d| d.run "rabbitmq" end end
docker run a container with the "rabbitmq" image. Note that
Vagrant uses the first parameter (the image name by default) to override any
settings used in a previous
run definition. Therefore, if you need to run
multiple containers from the same image then you must specify the
option (documented below) with a unique name.
In addition to the name, the
run method accepts a set of options, all optional:
image(string) - The image to run. This defaults to the first argument but can also be given here as an option.
auto_assign_name(boolean) - If true, the
--nameof the container will be set to the first argument of the run. By default this is true. If the name set contains a "/" (because of the image name), it will be replaced with "-". Therefore, if you do
d.run "foo/bar", then the name of the container will be "foo-bar".
daemonize(boolean) - If true, the "-d" flag is given to
docker runto daemonize the containers. By default this is true.
restart(string) - The restart policy for the container. Defaults to "always"
For example, here is how you would configure Docker to run a container with the Vagrant shared directory mounted inside of it:
Vagrant.configure("2") do |config| config.vm.provision "docker" do |d| d.run "ubuntu", cmd: "bash -l", args: "-v '/vagrant:/var/www'" end end
In case you need to run multiple containers based off the same image, you can do
so by providing different names and specifying the
image parameter to it:
Vagrant.configure("2") do |config| config.vm.provision "docker" do |d| d.run "db-1", image: "user/mysql" d.run "db-2", image: "user/mysql" end end
This section documents some other things related to the Docker provisioner that are generally useful to know if you are using this provisioner.
To customize this file, use a shell provisioner before the Docker provisioner that sets this file up. The Docker provisioner will not modify this file in a destructive way.