Only try to configure our DB if it's defined

roles/matrix/tasks/main.yml

@@ -38,6 +38,7 @@
             login_host: "{{ matrix_db_hostname }}"
             login_user: "{{ psql_ansible_user }}"
             login_password: "{{ psql_ansible_password }}"
+      when: matrix_db_hostname is defined
     - name: Set up Apache
       block:
         - name: Template out config

roles/pleroma/tasks/main.yml

@@ -50,6 +50,7 @@
             - citext
             - pg_trgm
             - uuid-ossp
+      when: pleroma_db_hostname is defined
     - name: Set up Apache
       block:
         - name: Enable modules