Add matrix_prometheus_container_network/matrix_prometheus_container_additional_networks

roles/custom/matrix-prometheus/tasks/validate_config.yml

@@ -5,3 +5,11 @@
     msg: >
       You need to enable `matrix_prometheus_scraper_synapse_enabled` and/or `matrix_prometheus_scraper_node_enabled` for Prometheus grab metrics.
   when: "not matrix_prometheus_scraper_synapse_enabled and not matrix_prometheus_scraper_node_enabled"
+
+- name: Fail if required Prometheus settings not defined
+  ansible.builtin.fail:
+    msg: >
+      You need to define a required configuration setting (`{{ item }}`).
+  when: "vars[item] == ''"
+  with_items:
+    - matrix_prometheus_container_network