---
layout: docs
page_title: Basic Usage - Docker Provider
sidebar_current: providers-docker-basics
description: |-
  The Docker provider in Vagrant behaves just like any other provider.
  If you are familiar with Vagrant already, then using the Docker provider
  should be intuitive and simple.
---

# Docker Basic Usage

The Docker provider in Vagrant behaves just like any other provider.
If you are familiar with Vagrant already, then using the Docker provider
should be intuitive and simple.

The Docker provider _does not_ require a `config.vm.box` setting. Since
the "base image" for a Docker container is pulled from the
Docker Index or
built from a Dockerfile, the box does not
add much value, and is optional for this provider.

## Docker Images

The first method that Vagrant can use to source a Docker container
is via an image. This image can be from any Docker registry. An
example is shown below:

```ruby
Vagrant.configure("2") do |config|
  config.vm.provider "docker" do |d|
    d.image = "foo/bar"
  end
end
```

When `vagrant up --provider=docker` is run, this will bring up the
image `foo/bar`.

This is useful for extra components of your application that it might
depend on: databases, queues, etc. Typically, the primary application
you are working on is built with a Dockerfile, or via a container with
SSH.

## Dockerfiles

Vagrant can also automatically build and run images based on a local
Dockerfile. This is useful for iterating on an application locally
that is built into an image later. An example is shown below:

```ruby
Vagrant.configure("2") do |config|
  config.vm.provider "docker" do |d|
    d.build_dir = "."
  end
end
```

The above configuration will look for a `Dockerfile` in the same
directory as the Vagrantfile. When `vagrant up --provider=docker` is run, Vagrant
automatically builds that Dockerfile and starts a container
based on that Dockerfile.

The Dockerfile is rebuilt when `vagrant reload` is called.

## Synced Folders and Networking

When using Docker, Vagrant automatically converts synced folders
and networking options into Docker volumes and forwarded ports.
You do not have to use the Docker-specific configurations to do this.
This helps keep your Vagrantfile similar to how it has always looked.

The Docker provider does not support specifying options for `owner` or `group`
on folders synced with a docker container.

### Volume Consistency

Docker's [volume consistency](https://docs.docker.com/v17.09/engine/admin/volumes/bind-mounts/) setting can be specified using the `docker_consistency` option when defining a synced folder. This can
[greatly improve performance on macOS](https://docs.docker.com/docker-for-mac/osxfs-caching). An example is shown using the `cached` and `delegated` settings:

```ruby
config.vm.synced_folder "/host/dir1", "/guest/dir1", docker_consistency: "cached"
config.vm.synced_folder "/host/dir2", "/guest/dir2", docker_consistency: "delegated"
```

## Host VM

If the system cannot run Linux containers natively, Vagrant automatically spins
up a "host VM" to run Docker. This allows your Docker-based Vagrant environments
to remain portable, without inconsistencies depending on the platform they are
running on.

Vagrant will spin up a single instance of a host VM and run multiple
containers on this one VM. This means that with the Docker provider,
you only have the overhead of one virtual machine, and only if it is
absolutely necessary.

By default, the host VM Vagrant spins up is
[backed by boot2docker](https://github.com/hashicorp/vagrant/blob/master/plugins/providers/docker/hostmachine/Vagrantfile),
because it launches quickly and uses little resources. But the host VM
can be customized to point to _any_ Vagrantfile. This allows the host VM
to more closely match production by running a VM running Ubuntu, RHEL,
etc. It can run any operating system supported by Vagrant.

-> **Synced folder note:** Vagrant will attempt to use the
"best" synced folder implementation it can. For boot2docker, this is
often rsync. In this case, make sure you have rsync installed on your
host machine. Vagrant will give you a human-friendly error message if
it is not.

An example of changing the host VM is shown below. Remember that this
is optional, and Vagrant will spin up a default host VM if it is not
specified:

```ruby
Vagrant.configure("2") do |config|
  config.vm.provider "docker" do |d|
    d.vagrant_vagrantfile = "../path/to/Vagrantfile"
  end
end
```

The host VM will be spun up at the first `vagrant up` where the provider
is Docker. To control this host VM, use the
[global-status command](/docs/cli/global-status.html)
along with global control.
