diff --git a/defaults/main.yml b/defaults/main.yml
index 6657aca..9507c49 100644
--- a/defaults/main.yml
+++ b/defaults/main.yml
@@ -21,6 +21,7 @@ matrix_dependencies:
   - tk-devel
   - redhat-rpm-config
   - python-virtualenv
+  - python36-devel
   - libffi-devel
   - openssl-devel
 
diff --git a/tasks/prepare.yml b/tasks/prepare.yml
index bb7541f..186ea61 100644
--- a/tasks/prepare.yml
+++ b/tasks/prepare.yml
@@ -58,3 +58,4 @@
       no_log: True
       when: matrix_postgres_user is defined
   delegate_to: "{{ matrix_postgres_server }}"
+  when: matrix_postgres_enabled