Add support for configuring rootfs path

References #30

lib/vagrant-lxc/action/create.rb

@@ -6,7 +6,9 @@ def call(env)
           base_name = env[:root_path].basename.to_s
           base_name.gsub!(/[^-a-z0-9_]/i, "")
 
-          machine_id         = env[:machine].provider.container.create(base_name, env[:machine].box.metadata)
+          target_rootfs_path = env[:machine].provider_config.target_rootfs_path
+
+          machine_id         = env[:machine].provider.container.create(base_name, target_rootfs_path, env[:machine].box.metadata)
           env[:machine].id   = machine_id
           env[:just_created] = true
           @app.call env

lib/vagrant-lxc/config.rb

@@ -6,8 +6,15 @@ class Config < Vagrant.plugin("2", :config)
       # @return [Array]
       attr_reader :start_opts
 
+      # Base directory to store container's rootfs
+      #
+      # Defaults to nil, which means it will be stored wherever the lxc template
+      # tells it to be stored
+      attr_accessor :target_rootfs_path
+
       def initialize
-        @start_opts  = []
+        @start_opts         = []
+        @target_rootfs_path = nil
       end
     end
   end

lib/vagrant-lxc/container.rb

@@ -36,10 +36,10 @@ def base_path
       end
 
       def rootfs_path
-        Pathname.new("#{base_path}/rootfs")
+        Pathname.new(base_path.join('config').read.match(/^lxc\.rootfs\s+=\s+(.+)$/)[1])
       end
 
-      def create(base_name, metadata = {})
+      def create(base_name, target_rootfs_path, metadata = {})
         @logger.debug('Creating container using lxc-create...')
 
         @name      = "#{base_name}-#{SecureRandom.hex(6)}"
@@ -50,7 +50,7 @@ def create(base_name, metadata = {})
         )
 
         @cli.name = @name
-        @cli.create(metadata.fetch('template-name'), meta_opts)
+        @cli.create(metadata.fetch('template-name'), target_rootfs_path, meta_opts)
 
         @name
       end

lib/vagrant-lxc/container/cli.rb

@@ -31,15 +31,18 @@ def state
           end
         end
 
-        def create(template, template_opts = {})
+        def create(template, target_rootfs_path, template_opts = {})
           extra = template_opts.to_a.flatten
           extra.unshift '--' unless extra.empty?
 
+          rootfs_args = target_rootfs_path ?
+            ['-B', 'dir', '--dir', target_rootfs_path] :
+            []
+
           run :create,
-              # lxc-create options
               '--template', template,
               '--name',     @name,
-              *extra
+              *(rootfs_args + extra)
         end
 
         def destroy

spec/unit/container/cli_spec.rb

@@ -33,19 +33,31 @@
     subject { described_class.new(name) }
 
     before do
-      subject.stub(:run)
-      subject.create(template, template_args)
+      subject.stub(:run) { |*args| @run_args = args }
+      subject.create(template, rootfs, template_args)
     end
 
-    it 'issues a lxc-create with provided template, container name and hash of arguments' do
-      subject.should have_received(:run).with(
-        :create,
-        '--template', template,
-        '--name',     name,
-        '--',
-        '--extra-param', 'param',
-        '--other',       'value'
-      )
+    context 'when no rootfs is passed' do
+      let(:rootfs) { nil }
+
+      it 'issues a lxc-create with provided template, container name and hash of arguments' do
+        subject.should have_received(:run).with(
+          :create,
+          '--template', template,
+          '--name',     name,
+          '--',
+          '--extra-param', 'param',
+          '--other',       'value'
+        )
+      end
+    end
+
+    context 'when the rootfs is passed' do
+      let(:rootfs) { 'rootfs_path' }
+
+      it 'issues a lxc-create with the right rootfs arguments' do
+        @run_args.join(' ').should =~ /-B dir --dir #{rootfs}/
+      end
     end
   end
 

spec/unit/container_spec.rb

@@ -37,20 +37,22 @@
     let(:suffix)          { 'random-suffix' }
     let(:template_name)   { 'template-name' }
     let(:rootfs_cache)    { '/path/to/cache' }
+    let(:target_rootfs)   { '/path/to/rootfs' }
     let(:public_key_path) { Vagrant.source_root.join('keys', 'vagrant.pub').expand_path.to_s }
     let(:cli)             { fire_double('Vagrant::LXC::Container::CLI', :create => true, :name= => true) }
 
     subject { described_class.new(name, cli) }
 
     before do
       SecureRandom.stub(hex: suffix)
-      subject.create base_name, 'template-name' => template_name, 'rootfs-cache-path' => rootfs_cache, 'template-opts' => { '--foo' => 'bar'}
+      subject.create base_name, target_rootfs, 'template-name' => template_name, 'rootfs-cache-path' => rootfs_cache, 'template-opts' => { '--foo' => 'bar'}
     end
 
     it 'creates container with the right arguments' do
       cli.should have_received(:name=).with("#{base_name}-#{suffix}")
       cli.should have_received(:create).with(
         template_name,
+        target_rootfs,
         '--auth-key' => public_key_path,
         '--cache'    => rootfs_cache,
         '--foo'      => 'bar'