This allows you to reinstall minos on a cluster if needed

No need for serial.
Clean out the venv and the pip cache since it might all have troubles.

playbooks/edx-east/minos.yml

@@ -2,9 +2,6 @@
   hosts: all
   become: True
   gather_facts: True
-  vars:
-    serial_count: 1
-  serial: "{{ serial_count }}"
   roles:
-    - aws
+    - common_vars
     - minos

playbooks/roles/minos/tasks/main.yml

@@ -79,6 +79,23 @@
     force: yes
     mode: "0600"
 
+- name: Clear pip cache
+  file:
+    path: "/root/.cache/pip"
+    state: absent
+
+- name: Clear virtualenv
+  file:
+    path: "{{ minos_app_dir }}/venvs/"
+    state: absent
+
+- name: recreate virtualenv
+  file:
+    path: "{{ minos_app_dir }}/venvs/"
+    state: directory
+    owner: "minos"
+    group: "{{ common_web_group }}"
+
 - name: Install python custom-requirements
   pip:
     name: "{{ item }}"