diff --git a/.gitignore b/.gitignore
index 3388eb148..f8cf0afc4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,6 +4,8 @@
 build/
 dist/
 
+AUTHORS
+ChangeLog
 GTAGS
 GRTAGS
 GPATH
diff --git a/ryu/hooks.py b/ryu/hooks.py
index d7a2a8ddf..9f3db6694 100644
--- a/ryu/hooks.py
+++ b/ryu/hooks.py
@@ -15,27 +15,10 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-import os
 import sys
-from setuptools.command import easy_install
 from ryu import version
 
 
-# Global variables in this module doesn't work as we expect
-# because, during the setup procedure, this module seems to be
-# copied (as a file) and can be loaded multiple times.
-# We save them into __main__ module instead.
-def _main_module():
-    return sys.modules['__main__']
-
-
-def save_orig():
-    """Save original easy_install.get_script_args.
-    This is necessary because pbr's setup_hook is sometimes called
-    before ours."""
-    _main_module()._orig_get_script_args = easy_install.get_script_args
-
-
 def setup_hook(config):
     """Filter config parsed from a setup.cfg to inject our defaults."""
     metadata = config['metadata']
@@ -46,19 +29,8 @@ def setup_hook(config):
 
     metadata['version'] = str(version)
 
-    # pbr's setup_hook replaces easy_install.get_script_args with
-    # their own version, override_get_script_args, prefering simpler
-    # scripts which are not aware of multi-version.
-    # prevent that by doing the opposite.  it's a horrible hack
-    # but we are in patching wars already...
     from pbr import packaging
 
-    def my_get_script_args(*args, **kwargs):
-        return _main_module()._orig_get_script_args(*args, **kwargs)
-
-    packaging.override_get_script_args = my_get_script_args
-    easy_install.get_script_args = my_get_script_args
-
     # another hack to allow setup from tarball.
     orig_get_version = packaging.get_version
 
diff --git a/setup.py b/setup.py
index fee79eb1a..77d87885a 100644
--- a/setup.py
+++ b/setup.py
@@ -15,10 +15,8 @@
 # limitations under the License.
 
 import setuptools
-import ryu.hooks
 
 
-ryu.hooks.save_orig()
 setuptools.setup(name='ryu',
                  setup_requires=['pbr'],
                  pbr=True)
diff --git a/tools/pip-requires b/tools/pip-requires
index 714cb3a63..e668c1900 100644
--- a/tools/pip-requires
+++ b/tools/pip-requires
@@ -1,8 +1,6 @@
 -r ../pip-requirements.txt
-# NOTE: OpenStack avoids some versions of eventlet, because of the
-# following issue.
-# https://github.com/eventlet/eventlet/issues/401
-eventlet==0.31.1
+eventlet>=0.41.0
+dnspython>=2.8.0
 msgpack>=0.4.0  # RPC library, BGP speaker(net_cntl)
 netaddr
 oslo.config>=2.5.0