Installs EPEL repository, sometimes required for python2-pip

postgresql/tasks/packages.yml

 ---
 
+- name: Install EPEL repository
+  yum:
+    conf_file: '/etc/yum.conf'
+    name:
+      - epel-release
+    state: present
+    update_cache: yes
+  when: (ansible_facts['distribution'] == "CentOS" and ansible_facts['distribution_major_version'] == "7" and use_external_epel)
+
 - name: Install ancillary packages for CentOS 7
   yum:
     conf_file: '/etc/yum.conf'