diff --git a/devstack/plugin.sh b/devstack/plugin.sh
index 1118c9f9c..435cd6733 100644
--- a/devstack/plugin.sh
+++ b/devstack/plugin.sh
@@ -335,9 +335,9 @@ function install_zeromq {
     if is_fedora; then
         install_package zeromq
     elif is_ubuntu; then
-        install_package libzmq1
+        install_package libzmq3-dev
     elif is_suse; then
-        install_package libzmq1
+        install_package libzmq3-dev
     fi
     # Necessary directory for socket location.
     sudo mkdir -p /var/run/openstack
diff --git a/devstack/redis_driver b/devstack/redis_driver
index aad77d861..aed6a7e1b 100644
--- a/devstack/redis_driver
+++ b/devstack/redis_driver
@@ -11,7 +11,6 @@
 # - nb_db_driver_configure
 
 REDIS_VERSION=3.0.6
-RUBY_VERSION=2.3
 
 function _redis_env {
     # REMOTE_DB_* initialized after sourcing
@@ -74,15 +73,7 @@ function nb_db_driver_install_server {
                 _configure_redis
             fi
 
-            mkdir -p $DEST/ruby
-            if [ ! -f "$DEST/ruby/ruby-$RUBY_VERSION.0.tar.gz" ]; then
-                wget https://cache.ruby-lang.org/pub/ruby/$RUBY_VERSION/ruby-$RUBY_VERSION.0.tar.gz -O $DEST/ruby/ruby-$RUBY_VERSION.0.tar.gz
-            fi
-            tar xzvf $DEST/ruby/ruby-$RUBY_VERSION.0.tar.gz -C $DEST/ruby
-            cd $DEST/ruby/ruby-$RUBY_VERSION.0
-            sudo ./configure
-            sudo make
-            sudo make install
+            install_package -y ruby
 
             if ! sudo gem list redis | grep -q redis; then
                 sudo gem source -a $DF_RUBY_SOURCE_ADD
diff --git a/dragonflow/switch/drivers/ovs/df_ovs_driver.py b/dragonflow/switch/drivers/ovs/df_ovs_driver.py
index 6a5534fd3..0f1f2b9db 100644
--- a/dragonflow/switch/drivers/ovs/df_ovs_driver.py
+++ b/dragonflow/switch/drivers/ovs/df_ovs_driver.py
@@ -42,6 +42,13 @@ class DfOvsDriver(df_switch_driver.DfSwitchDriver):
     def initialize(self, db_change_callback, neutron_notifier):
         super(DfOvsDriver, self).initialize(db_change_callback,
                                             neutron_notifier)
+        self._initialize_app()
+        # The OfctlService is needed to support the 'get_flows' method
+        self._initialize_service()
+
+    def _initialize_app(self):
+        if self.open_flow_app:
+            self.app_mgr.uninstantiate(self.open_flow_app.name)
         self.open_flow_app = self.app_mgr.instantiate(
             os_ken_base_app.OsKenDFAdapter,
             nb_api=self.nb_api,
@@ -49,7 +56,10 @@ class DfOvsDriver(df_switch_driver.DfSwitchDriver):
             neutron_server_notifier=self.neutron_notifier,
             db_change_callback=self.db_change_callback
         )
-        # The OfctlService is needed to support the 'get_flows' method
+
+    def _initialize_service(self):
+        if self.open_flow_service:
+            self.app_mgr.uninstantiate(self.open_flow_service.name)
         self.open_flow_service = self.app_mgr.instantiate(
             of_service.OfctlService)
 
diff --git a/dragonflow/tests/fullstack/apps/test_l2.py b/dragonflow/tests/fullstack/apps/test_l2.py
index dc3141a80..740a31302 100644
--- a/dragonflow/tests/fullstack/apps/test_l2.py
+++ b/dragonflow/tests/fullstack/apps/test_l2.py
@@ -10,6 +10,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import testtools
 import time
 
 from neutron.agent.common import utils
@@ -225,6 +226,7 @@ class TestNeighborAdvertiser(test_base.DFTestBase):
                        'net.ipv6.conf.default.router_solicitations={}'.
                        format(self.router_solicit_conf)], run_as_root=True)
 
+    @testtools.skip('bug/1820977')
     def test_simple_response(self):
         """
         2 ports on 1 subnet. 1 port asks for MAC of other.