Update docs for Prometheus: move other relevant instructions

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

docs/configuring-playbook-prometheus-grafana.md

@@ -84,11 +84,12 @@ matrix_prometheus_nginxlog_exporter_docker_image: path/to/docker/image:tag
 
 ### Extending the configuration
 
-There are some additional things you may wish to configure about Prometheus.
+There are some additional things you may wish to configure about Prometheus and its add-on.
 
 Take a look at:
 
 - [Prometheus role](https://github.com/mother-of-all-self-hosting/ansible-role-prometheus)'s [`defaults/main.yml`](https://github.com/mother-of-all-self-hosting/ansible-role-prometheus/blob/main/defaults/main.yml) for some variables that you can customize via your `vars.yml` file. You can override settings (even those that don't have dedicated playbook variables) using the `prometheus_configuration_extension_yaml` variable
+- `roles/custom/matrix-prometheus-nginxlog-exporter/defaults/main.yml` for some variables that you can customize via your `vars.yml` file
 
 ## Adjusting the playbook configuration — Grafana
 
@@ -208,6 +209,7 @@ As with all other services, you can find the logs in [systemd-journald](https://
 - `journalctl -fu matrix-prometheus` for Prometheus
 - `journalctl -fu matrix-prometheus-node-exporter` for Node Exporter
 - `journalctl -fu matrix-prometheus-postgres-exporter` for PostgreSQL Server Exporter
+- `journalctl -fu matrix-prometheus-nginxlog-exporter` for prometheus-nginxlog-exporter
 - `journalctl -fu matrix-grafana` for Grafana
 
 ## More information

docs/configuring-playbook-prometheus-nginxlog.md

@@ -25,14 +25,6 @@ When using an external Prometheus server, you'll need to expose metrics publicly
 
 For password-protection, use or (`matrix_prometheus_nginxlog_exporter_container_labels_metrics_middleware_basic_auth_enabled` and `matrix_prometheus_nginxlog_exporter_container_labels_metrics_middleware_basic_auth_users`).
 
-### Extending the configuration
-
-There are some additional things you may wish to configure about the component.
-
-Take a look at:
-
-- `roles/custom/matrix-prometheus-nginxlog-exporter/defaults/main.yml` for some variables that you can customize via your `vars.yml` file
-
 ## Installing
 
 After configuring the playbook, run it with [playbook tags](playbook-tags.md) as below:
@@ -45,7 +37,3 @@ ansible-playbook -i inventory/hosts setup.yml --tags=setup-all,start
 The shortcut commands with the [`just` program](just.md) are also available: `just install-all` or `just setup-all`
 
 `just install-all` is useful for maintaining your setup quickly ([2x-5x faster](../CHANGELOG.md#2x-5x-performance-improvements-in-playbook-runtime) than `just setup-all`) when its components remain unchanged. If you adjust your `vars.yml` to remove other components, you'd need to run `just setup-all`, or these components will still remain installed. Note these shortcuts run the `ensure-matrix-users-created` tag too.
-
-## Troubleshooting
-
-As with all other services, you can find the logs in [systemd-journald](https://www.freedesktop.org/software/systemd/man/systemd-journald.service.html) by logging in to the server with SSH and running `journalctl -fu matrix-prometheus-nginxlog-exporter`.