Fix /dev populating during image building

It turns out that /dev has got broken links during image building.
This leads to fail of installing tricky packages such as dkms.

Having /dev/fd -> /proc/self/fd totally resolves that issue.

Change-Id: I72865f2b2adcb431d959fa2a73b51d9abad5914b
Closes-Bug: #1485565

fuel_agent/manager.py

@@ -652,6 +652,8 @@ class Manager(object):
             utils.makedirs_if_not_exists(proc_path)
             fu.mount_bind(chroot, '/proc')
 
+            bu.populate_basic_dev(chroot)
+
             LOG.debug('Installing packages using apt-get: %s',
                       ' '.join(packages))
             bu.run_apt_get(chroot, packages=packages,

fuel_agent/tests/test_build_utils.py

@@ -471,6 +471,16 @@ class BuildUtilsTestCase(unittest2.TestCase):
                       'fake_force_ipv4')]
         self.assertEqual(expected_join_calls, mock_path.join.call_args_list)
 
+    @mock.patch.object(bu.utils, 'execute')
+    def test_populate_basic_dev(self, mock_execute):
+        bu.populate_basic_dev('fake_chroot')
+        expected_execute_calls = [
+            mock.call('chroot', 'fake_chroot', 'rm', '-fr', '/dev/fd'),
+            mock.call('chroot', 'fake_chroot', 'ln', '-s', '/proc/self/fd',
+                      '/dev/fd'),
+        ]
+        self.assertEqual(expected_execute_calls, mock_execute.call_args_list)
+
     @mock.patch('gzip.open')
     @mock.patch.object(os, 'remove')
     def test_containerize_gzip(self, mock_remove, mock_gzip):

fuel_agent/tests/test_manager.py

@@ -872,6 +872,7 @@ class TestImageBuild(unittest2.TestCase):
             mock.call('tune2fs', '-O', 'has_journal', '/dev/loop0')],
             mock_utils.execute.call_args_list)
         mock_fu.mount_bind.assert_called_once_with('/tmp/imgdir', '/proc')
+        mock_bu.populate_basic_dev.assert_called_once_with('/tmp/imgdir')
         mock_bu.run_apt_get.assert_called_once_with(
             '/tmp/imgdir', packages=['fakepackage1', 'fakepackage2'],
             attempts=CONF.fetch_packages_attempts)

fuel_agent/utils/build.py

@@ -258,6 +258,14 @@ def get_free_loop_device(loop_device_major_number=7,
     raise errors.NoFreeLoopDevices('Free loop device not found')
 
 
+def populate_basic_dev(chroot):
+    """Populates /dev with basic files, links, device nodes."""
+    # prevent failures related with /dev/fd/62
+    utils.execute('chroot', chroot, 'rm', '-fr', '/dev/fd')
+    utils.execute('chroot', chroot,
+                  'ln', '-s', '/proc/self/fd', '/dev/fd')
+
+
 def create_sparse_tmp_file(dir, suffix, size=8192):
     """Creates sparse file.