diff --git a/lib/vagrant/environment.rb b/lib/vagrant/environment.rb
index 8189b3337..cf37ffeb4 100644
--- a/lib/vagrant/environment.rb
+++ b/lib/vagrant/environment.rb
@@ -390,6 +390,7 @@ module Vagrant
         # reset to false so we don't think we have a lock when we
         # actually don't.
         @locks.delete(name)
+        @logger.info("Released process lock: #{name}")
       end
 
       # Clean up the lock file, this requires another lock
diff --git a/lib/vagrant/ui.rb b/lib/vagrant/ui.rb
index 08af9913d..3ec7821e2 100644
--- a/lib/vagrant/ui.rb
+++ b/lib/vagrant/ui.rb
@@ -296,8 +296,13 @@ module Vagrant
         target = @prefix
         target = opts[:target] if opts.has_key?(:target)
 
+        # Get the lines. The first default is because if the message
+        # is an empty string, then we want to still use the empty string.
+        lines = [message]
+        lines = message.split("\n") if message != ""
+
         # Otherwise, make sure to prefix every line properly
-        message.split("\n").map do |line|
+        lines.map do |line|
           "#{prefix}#{target}: #{line}"
         end.join("\n")
       end
diff --git a/plugins/providers/docker/action.rb b/plugins/providers/docker/action.rb
index f6faddaee..64f80186d 100644
--- a/plugins/providers/docker/action.rb
+++ b/plugins/providers/docker/action.rb
@@ -4,6 +4,32 @@ module VagrantPlugins
       # Include the built-in modules so we can use them as top-level things.
       include Vagrant::Action::Builtin
 
+      # This action starts another container just like the real one running
+      # but only for the purpose of running a single command rather than
+      # to exist long-running.
+      def self.action_run_command
+        Vagrant::Action::Builder.new.tap do |b|
+          b.use ConfigValidate
+
+          b.use Call, IsState, :host_state_unknown do |env, b2|
+            if env[:result]
+              raise "Invalid usage"
+            end
+          end
+
+          b.use Call, IsState, :not_created do |env, b2|
+            if env[:result]
+              b2.use Message,
+                I18n.t("docker_provider.messages.not_created_original")
+              next
+            else
+            end
+          end
+
+          b.use action_start
+        end
+      end
+
       # This action brings the "machine" up from nothing, including creating the
       # container, configuring metadata, and booting.
       def self.action_up
@@ -198,16 +224,18 @@ module VagrantPlugins
       def self.action_start
         Vagrant::Action::Builder.new.tap do |b|
           b.use Call, IsState, :running do |env, b2|
-            # If the container is running, then our work here is done, exit
-            next if env[:result]
+            # If the container is running and we're doing a run, we're done
+            next if env[:result] && env[:machine_action] != :run_command
 
-            b2.use Call, HasSSH do |env2, b3|
-              if env2[:result]
-                b3.use Provision
-              else
-                b3.use Message,
-                  I18n.t("docker_provider.messages.provision_no_ssh"),
-                  post: true
+            if env[:machine_action] != :run_command
+              b2.use Call, HasSSH do |env2, b3|
+                if env2[:result]
+                  b3.use Provision
+                else
+                  b3.use Message,
+                    I18n.t("docker_provider.messages.provision_no_ssh"),
+                    post: true
+                end
               end
             end
 
@@ -224,7 +252,7 @@ module VagrantPlugins
             b2.use PrepareNFSSettings
             b2.use Build
 
-            # If the VM is NOT created yet, then do some setup steps
+            # If the container is NOT created yet, then do some setup steps
             # necessary for creating it.
             b2.use Call, IsState, :not_created do |env2, b3|
               if env2[:result]
@@ -240,12 +268,18 @@ module VagrantPlugins
               end
             end
 
-            b2.use Start
-            b2.use WaitForRunning
+            # If we're doing a one-off command, then we create
+            if env[:machine_action] == :run_command
+              b2.use SyncedFolders
+              b2.use Create
+            else
+              b2.use Start
+              b2.use WaitForRunning
 
-            b2.use Call, HasSSH do |env2, b3|
-              if env2[:result]
-                b3.use WaitForCommunicator
+              b2.use Call, HasSSH do |env2, b3|
+                if env2[:result]
+                  b3.use WaitForCommunicator
+                end
               end
             end
           end
diff --git a/plugins/providers/docker/action/create.rb b/plugins/providers/docker/action/create.rb
index 031573e52..67ab35e6d 100644
--- a/plugins/providers/docker/action/create.rb
+++ b/plugins/providers/docker/action/create.rb
@@ -15,9 +15,27 @@ module VagrantPlugins
 
           params = create_params
 
+          # If we're running a single command, we modify the params a bit
+          if env[:machine_action] == :run_command
+            # Use the command that is given to us
+            params[:cmd] = env[:run_command]
+
+            # Don't detach, we want to watch the command run
+            params[:detach] = false
+
+            # No ports should be shared to the host
+            params[:ports] = []
+
+            # We link to our original container
+            # TODO
+          end
+
           env[:ui].output(I18n.t("docker_provider.creating"))
           env[:ui].detail("  Name: #{params[:name]}")
           env[:ui].detail(" Image: #{params[:image]}")
+          if params[:cmd]
+            env[:ui].detail("   Cmd: #{params[:cmd].join(" ")}")
+          end
           params[:volumes].each do |volume|
             env[:ui].detail("Volume: #{volume}")
           end
@@ -28,12 +46,23 @@ module VagrantPlugins
             env[:ui].detail("  Link: #{name}:#{other}")
           end
 
-          cid = @driver.create(params)
+          if env[:machine_action] != :run_command
+            # For regular "ups" create it and get the CID
+            cid = @driver.create(params)
+            env[:ui].detail(" \n"+I18n.t(
+              "docker_provider.created", id: cid[0...16]))
+            @machine.id = cid
+          elsif params[:detach]
+            env[:ui].detail(" \n"+I18n.t("docker_provider.running_detached"))
+          else
+            # For run commands, we run it and stream back the output
+            env[:ui].detail(" \n"+I18n.t("docker_provider.running")+"\n ")
+            @driver.create(params) do |type, data|
+              env[:ui].detail(data)
+            end
+          end
 
-          env[:ui].detail(" \n"+I18n.t(
-            "docker_provider.created", id: cid[0...16]))
-          @machine.id = cid
-          @app.call(env)
+            @app.call(env)
         end
 
         def create_params
@@ -55,7 +84,9 @@ module VagrantPlugins
 
           {
             cmd:        @provider_config.cmd,
+            detach:     true,
             env:        @provider_config.env,
+            expose:     @provider_config.expose,
             extra_args: @provider_config.create_args,
             hostname:   @machine_config.vm.hostname,
             image:      image,
diff --git a/plugins/providers/docker/command/run.rb b/plugins/providers/docker/command/run.rb
new file mode 100644
index 000000000..dee9f01ce
--- /dev/null
+++ b/plugins/providers/docker/command/run.rb
@@ -0,0 +1,70 @@
+module VagrantPlugins
+  module DockerProvider
+    module Command
+      class Run < Vagrant.plugin("2", :command)
+        def self.synopsis
+          "run a one-off command in the context of a container"
+        end
+
+        def execute
+          options = {}
+          options[:detach] = false
+
+          opts = OptionParser.new do |o|
+            o.banner = "Usage: vagrant docker-run [command...]"
+            o.separator ""
+            o.separator "Options:"
+            o.separator ""
+
+            o.on("--[no-]detach", "Run in the background") do |d|
+              options[:detach] = d
+            end
+          end
+
+          # Parse out the extra args to send to SSH, which is everything
+          # after the "--"
+          split_index = @argv.index("--")
+          if !split_index
+            @env.ui.error(I18n.t("docker_provider.run_command_required"))
+            return 1
+          end
+
+          command = @argv.drop(split_index + 1)
+          @argv   = @argv.take(split_index)
+
+          # Parse the options
+          argv = parse_options(opts)
+          return if !argv
+
+          any_success = false
+          with_target_vms(argv) do |machine|
+            if machine.provider_name != :docker
+              machine.ui.output(I18n.t("docker_provider.not_docker_provider"))
+              next
+            end
+
+            state = machine.state
+            if state == :host_state_unknown
+              machine.ui.output(I18n.t("docker_provider.logs_host_state_unknown"))
+              next
+            elsif state == :not_created
+              machine.ui.output(I18n.t("docker_provider.not_created_skip"))
+              next
+            end
+
+            # At least one was run!
+            any_success = true
+
+            # Run it!
+            machine.action(
+              :run_command,
+              run_command: command,
+              run_detach: options[:detach])
+          end
+
+          return any_success ? 0 : 1
+        end
+      end
+    end
+  end
+end
diff --git a/plugins/providers/docker/config.rb b/plugins/providers/docker/config.rb
index d156b2143..27b6713cb 100644
--- a/plugins/providers/docker/config.rb
+++ b/plugins/providers/docker/config.rb
@@ -22,6 +22,12 @@ module VagrantPlugins
       # @return [Hash]
       attr_accessor :env
 
+      # Ports to expose from the container but not to the host machine.
+      # This is useful for links.
+      #
+      # @return [Array<Integer>]
+      attr_accessor :expose
+
       # Force using a proxy VM, even on Linux hosts.
       #
       # @return [Boolean]
@@ -71,6 +77,7 @@ module VagrantPlugins
         @cmd        = UNSET_VALUE
         @create_args = []
         @env        = {}
+        @expose     = []
         @force_host_vm = UNSET_VALUE
         @has_ssh    = UNSET_VALUE
         @image      = UNSET_VALUE
@@ -108,6 +115,10 @@ module VagrantPlugins
           env.merge!(other.env) if other.env
           result.env = env
 
+          expose = self.expose.dup
+          expose += other.expose
+          result.instance_variable_set(:@expose, expose)
+
           links = _links.dup
           links += other._links
           result.instance_variable_set(:@links, links)
@@ -127,6 +138,8 @@ module VagrantPlugins
         @remains_running = true if @remains_running == UNSET_VALUE
         @vagrant_machine = nil if @vagrant_machine == UNSET_VALUE
         @vagrant_vagrantfile = nil if @vagrant_vagrantfile == UNSET_VALUE
+
+        @expose.uniq!
       end
 
       def validate(machine)
diff --git a/plugins/providers/docker/driver.rb b/plugins/providers/docker/driver.rb
index 415b40aaf..aa43ca91b 100644
--- a/plugins/providers/docker/driver.rb
+++ b/plugins/providers/docker/driver.rb
@@ -25,7 +25,7 @@ module VagrantPlugins
         match[1]
       end
 
-      def create(params)
+      def create(params, &block)
         image   = params.fetch(:image)
         links   = params.fetch(:links)
         ports   = Array(params[:ports])
@@ -33,9 +33,12 @@ module VagrantPlugins
         name    = params.fetch(:name)
         cmd     = Array(params.fetch(:cmd))
         env     = params.fetch(:env)
+        expose  = Array(params[:expose])
 
-        run_cmd = %W(docker run --name #{name} -d)
+        run_cmd = %W(docker run --name #{name})
+        run_cmd << "-d" if params[:detach]
         run_cmd += env.map { |k,v| ['-e', "#{k}=#{v}"] }
+        run_cmd += expose.map { |p| ['--expose', "#{p}"] }
         run_cmd += links.map { |k, v| ['--link', "#{k}:#{v}"] }
         run_cmd += ports.map { |p| ['-p', p.to_s] }
         run_cmd += volumes.map { |v| ['-v', v.to_s] }
@@ -44,7 +47,7 @@ module VagrantPlugins
         run_cmd += params[:extra_args] if params[:extra_args]
         run_cmd += [image, cmd]
 
-        execute(*run_cmd.flatten).chomp
+        execute(*run_cmd.flatten, &block).chomp
       end
 
       def state(cid)
diff --git a/plugins/providers/docker/executor/vagrant.rb b/plugins/providers/docker/executor/vagrant.rb
index 046686c62..85f274614 100644
--- a/plugins/providers/docker/executor/vagrant.rb
+++ b/plugins/providers/docker/executor/vagrant.rb
@@ -20,7 +20,7 @@ module VagrantPlugins
           # We have to do this because boot2docker outputs a login shell
           # boot2docker version that we get otherwise and messes up output.
           start_fence = "========== VAGRANT DOCKER BEGIN =========="
-          ssh_cmd     = "echo \"#{start_fence}\"; #{cmd}"
+          ssh_cmd     = "echo -n \"#{start_fence}\"; #{cmd}"
 
           stderr = ""
           stdout = ""
@@ -42,8 +42,8 @@ module VagrantPlugins
 
                 # We're now fenced, send all the data through
                 if block
-                  block.call(:stdout, stdout)
-                  block.call(:stderr, stderr)
+                  block.call(:stdout, stdout) if stdout != ""
+                  block.call(:stderr, stderr) if stderr != ""
                 end
               end
             else
diff --git a/plugins/providers/docker/plugin.rb b/plugins/providers/docker/plugin.rb
index 1073f15e8..b6988661b 100644
--- a/plugins/providers/docker/plugin.rb
+++ b/plugins/providers/docker/plugin.rb
@@ -28,6 +28,12 @@ module VagrantPlugins
         Command::Logs
       end
 
+      command("docker-run", primary: false) do
+        require_relative "command/run"
+        init!
+        Command::Run
+      end
+
       communicator(:docker_hostvm) do
         require_relative "communicator"
         init!
diff --git a/plugins/providers/virtualbox/provider.rb b/plugins/providers/virtualbox/provider.rb
index a52c07fb3..70adf34ef 100644
--- a/plugins/providers/virtualbox/provider.rb
+++ b/plugins/providers/virtualbox/provider.rb
@@ -56,9 +56,8 @@ module VagrantPlugins
 
       # Returns the SSH info for accessing the VirtualBox VM.
       def ssh_info
-        # If the VM is not created then we cannot possibly SSH into it, so
-        # we return nil.
-        return nil if state.id == :not_created
+        # If the VM is not running that we can't possibly SSH into it
+        return nil if state.id != :running
 
         # Return what we know. The host is always "127.0.0.1" because
         # VirtualBox VMs are always local. The port we try to discover
diff --git a/templates/locales/providers_docker.yml b/templates/locales/providers_docker.yml
index b4e27565f..3652d2c97 100644
--- a/templates/locales/providers_docker.yml
+++ b/templates/locales/providers_docker.yml
@@ -37,6 +37,18 @@ en:
       Container not created. Skipping.
     not_docker_provider: |-
       Not backed by Docker provider. Skipping.
+    run_command_required: |-
+      `vagrant docker-run` requires a command to execute. This command
+      must be specified after a `--` in the command line. This is used
+      to separate possible machine names and options from the actual
+      command to execute. An example is shown below:
+
+        vagrant docker-run web -- rails new .
+
+    running: |-
+      Container is starting. Output will stream in below...
+    running_detached: |-
+      Container is started detached.
     ssh_through_host_vm: |-
       SSH will be proxied through the Docker virtual machine since we're
       not running Docker natively. This is just a notice, and not an error.
@@ -52,6 +64,9 @@ en:
         Deleting the container...
       not_created: |-
         The container hasn't been created yet.
+      not_created_original: |-
+        The original container hasn't been created yet. Run `vagrant up`
+        for this machine first.
       not_running: |-
         The container is not currently running.
       provision_no_ssh: |-
diff --git a/test/unit/plugins/providers/docker/config_spec.rb b/test/unit/plugins/providers/docker/config_spec.rb
index cb316238d..c93bf2c89 100644
--- a/test/unit/plugins/providers/docker/config_spec.rb
+++ b/test/unit/plugins/providers/docker/config_spec.rb
@@ -39,6 +39,7 @@ describe VagrantPlugins::DockerProvider::Config do
     before { subject.finalize! }
 
     its(:build_dir) { should be_nil }
+    its(:expose) { should eq([]) }
     its(:cmd) { should eq([]) }
     its(:env) { should eq({}) }
     its(:force_host_vm) { should be_false }
@@ -82,6 +83,20 @@ describe VagrantPlugins::DockerProvider::Config do
     end
   end
 
+  describe "#expose" do
+    before do
+      valid_defaults
+    end
+
+    it "uniqs the ports" do
+      subject.expose = [1, 1, 4, 5]
+      subject.finalize!
+      assert_valid
+
+      expect(subject.expose).to eq([1, 4, 5])
+    end
+  end
+
   describe "#image" do
     it "should be valid if set" do
       subject.image = "foo"
@@ -166,6 +181,16 @@ describe VagrantPlugins::DockerProvider::Config do
       end
     end
 
+    context "exposed ports" do
+      it "merges the exposed ports" do
+        one.expose << 1234
+        two.expose = [42, 54]
+
+        expect(subject.expose).to eq([
+          1234, 42, 54])
+      end
+    end
+
     context "links" do
       it "should merge the links" do
         one.link "foo"