matrix-docker-ansible-deploy/roles/matrix-prometheus-node-exporter/tasks/validate_config.yml

---

- name: Fail if Synapse metrics or Prometheus Node Exporter not enabled
  fail:
    msg: >
      You need to enable `matrix_synapse_metrics_enabled` and/or `matrix_prometheus_node_exporter_enabled` for Prometheus grab metrics.
  when: "not matrix_synapse_metrics_enabled and not matrix_prometheus_node_exporter_enabled"