diff --git a/Dockerfile b/Dockerfile
index a15ddc9..a823cda 100755
--- a/Dockerfile
+++ b/Dockerfile
@@ -44,12 +44,13 @@
     curl \
     iptables \
     iputils-ping \
-    sudo
+    sudo \
+    vim
 
 # install containernet (using its Ansible playbook)
-# Attention: Containernet installation fixed to specific commit. Change to update to latest Containernet version.
-RUN git clone https://github.com/containernet/containernet.git && \
-    (cd containernet && git checkout 6fcee82e192c8c0e6447650d6f512842185529ee)
+#RUN git clone https://github.com/containernet/containernet.git && \
+#    (cd containernet && git checkout 6fcee82e192c8c0e6447650d6f512842185529ee)
+RUN git clone https://github.com/containernet/containernet.git
 WORKDIR /containernet/ansible
 RUN ansible-playbook -i "localhost," -c local --skip-tags "notindocker" install.yml
 
diff --git a/ansible/install.yml b/ansible/install.yml
index 0ee1e44..4cf9be7 100755
--- a/ansible/install.yml
+++ b/ansible/install.yml
@@ -63,7 +63,7 @@
      pip: name=oslo.config state=latest
 
    - name: install pytest
-     pip: name=pytest state=latest
+     pip: name=pytest version=4.6.4
 
    - name: install Flask
      pip: name=Flask state=latest
diff --git a/setup.py b/setup.py
index 7442fda..ef1f0fe 100755
--- a/setup.py
+++ b/setup.py
@@ -47,7 +47,7 @@
           'six>=1.9',
           'ryu',
           'oslo.config',
-          'pytest',
+          'pytest<=4.6.4',
           'Flask',
           'flask_restful',
           'docker==2.0.2',
@@ -70,5 +70,5 @@
           ],
       },
       setup_requires=['pytest-runner'],
-      tests_require=['pytest', 'more-itertools<=5.0.0'],
+      tests_require=['pytest<=4.6.4', 'more-itertools<=5.0.0'],
       )