Pin the pip version to 7.1.2

latest pip 8.0 can not override the system installed package

Closes-Bug: #1536023
Change-Id: Ida07fc9e2e8aaffb3caaffce75ec4cbf8a4994e8

docker/kolla-ansible/Dockerfile.j2

@@ -33,9 +33,15 @@ RUN apt-get -y --no-install-recommends install \
 
 {% endif %}
 
+# TODO(jeffrey4l): Pin the pip to the 7.1.2. version. latest pip
+# (now 8.0) can not install the package when conflict with the
+# system. The best solution should use the virtualenv for
+# isolation or following bug is fixed:
+# https://github.com/pypa/pip/pull/3389
 RUN curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py \
     && python get-pip.py \
     && rm get-pip.py \
+    && pip install pip==7.1.2 \
     && pip --no-cache-dir install --upgrade wheel \
     && pip --no-cache-dir install \
         MySQL-python \

docker/openstack-base/Dockerfile.j2

@@ -105,13 +105,20 @@ RUN apt-get install -y --no-install-recommends \
     {% endif %}
 
 ADD openstack-base-archive /openstack-base-source
+# TODO(jeffrey4l): Pin the pip to the 7.1.2. version. latest pip
+# (now 8.0) can not install the package when conflict with the
+# system. The best solution should use the virtualenv for
+# isolation or following bug is fixed:
+# https://github.com/pypa/pip/pull/3389
 RUN ln -s openstack-base-source/* /requirements \
     && mkdir /var/lib/kolla \
     && curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py \
     && python get-pip.py \
     && rm get-pip.py \
+    && pip install pip==7.1.2 \
     && pip --no-cache-dir install -U virtualenv \
     && virtualenv --system-site-packages /var/lib/kolla/venv \
+    && /var/lib/kolla/venv/bin/pip --no-cache-dir install pip==7.1.2 \
     && /var/lib/kolla/venv/bin/pip --no-cache-dir install --upgrade -c requirements/upper-constraints.txt \
         jinja2 \
         kazoo \