provisioners/docker: config to disablize -d flag

CHANGELOG.md

@@ -37,6 +37,7 @@ IMPROVEMENTS:
   - provisioners/chef-solo: New config `synced_folder_type` replaces the
     `nfs` option. This can be used to set the synced folders the provisioner
     needs to any type. [GH-2709]
+  - provisioners/docker: Can start a container without daemonization.
   - provisioners/puppet: New config `synced_folder_type` replaces the
     `nfs` option. This can be used to set the synced folders the provisioner
     needs to any type. [GH-2709]

plugins/provisioners/docker/client.rb

@@ -75,7 +75,8 @@ module VagrantPlugins
       end
 
       def create_container(config)
-        args = "-cidfile=#{config[:cidfile]} -d "
+        args = "-cidfile=#{config[:cidfile]} "
+        args << "-d " if config[:daemonize]
         args << config[:args] if config[:args]
         @machine.communicate.sudo %[
           rm -f #{config[:cidfile]}

plugins/provisioners/docker/config.rb

@@ -32,6 +32,7 @@ module VagrantPlugins
       def run(name, **options)
         params = options.dup
         params[:image] ||= name
+        params[:daemonize] = true if !params.has_key?(:daemonize)
 
         # TODO: Validate provided parameters before assignment
         @containers[name.to_s] = params

test/unit/plugins/provisioners/docker/config_test.rb

@@ -40,6 +40,32 @@ describe VagrantPlugins::Docker::Config do
     end
   end
 
+  describe "#run" do
+    it "runs the given image" do
+      subject.run("foo")
+
+      subject.finalize!
+      expect(subject.containers).to eql({
+        "foo" => {
+          daemonize: true,
+          image: "foo",
+        }
+      })
+    end
+
+    it "can not daemonize" do
+      subject.run("foo", daemonize: false)
+
+      subject.finalize!
+      expect(subject.containers).to eql({
+        "foo" => {
+          daemonize: false,
+          image: "foo",
+        }
+      })
+    end
+  end
+
   describe "#version" do
     it "defaults to latest" do
       subject.finalize!

website/docs/source/v2/provisioning/docker.html.md

@@ -132,6 +132,9 @@ to the name, the `run` method accepts a set of options, all optional:
 * `args` (string) - Extra arguments for [`docker run`](http://docs.docker.io/en/latest/commandline/cli/#run)
   on the command line. These are raw arguments that are passed directly to Docker.
 
+* `daemonize` (boolean) - If true, the "-d" flag is given to `docker run` to
+  daemonize the containers. By default this is true.
+
 For example, here is how you would configure Docker to run a container
 with the Vagrant shared directory mounted inside of it: