Replace matrix-prometheus with an external Prometheus role

CHANGELOG.md

@@ -1,3 +1,22 @@
+# 2023-03-21
+
+## The matrix-prometheus role lives independently now
+
+**TLDR**: the `matrix-prometheus` role is now included from the [ansible-role-prometheus](https://github.com/mother-of-all-self-hosting/ansible-role-prometheus) repository, part of the [MASH playbook](https://github.com/mother-of-all-self-hosting/mash-playbook). Some variables have been renamed. All functionality remains intact.
+
+The `matrix-prometheus` role has been relocated in its own repository, part of the [MASH playbook](https://github.com/mother-of-all-self-hosting/mash-playbook) project - an Ansible playbook for self-hosting [a growing list of FOSS software](https://github.com/mother-of-all-self-hosting/mash-playbook/blob/main/docs/supported-services.md). If hosting a Prometheus stack on the Matrix server itself did not stand right with you or you always wanted to host most stuff, you can now use this new playbook to do so.
+
+Extracting the Prometheus role out of this Matrix playbook required huge internal refactoring to the way the Prometheus configuration (scraping jobs) is generated. If you notice any breakage after upgrading, let us know.
+
+You need to **update you roles** (`just roles` or `make roles`) regardless of whether you're using Prometheus or not.
+
+If you're making use of Prometheus via this playbook, you will need to update variable references in your `vars.yml` file:
+
+  - `matrix_prometheus_docker_image_` -> `matrix_prometheus_container_image_`
+  - `matrix_prometheus_` -> `prometheus_`
+  - some other internal variables have changed, but the playbook will tell you about them
+
+
 # 2023-03-12
 
 ## synapse-auto-compressor support
@@ -830,7 +849,7 @@ See our [Setting up the ntfy push notifications server](docs/configuring-playboo
 
 **If you are using the [Hookshot bridge](docs/configuring-playbook-bridge-hookshot.md)**, you may find that:
 1. **Metrics may not be enabled by default anymore**:
-  - If Prometheus is enabled (`matrix_prometheus_enabled: true`), then Hookshot metrics will be enabled automatically (`matrix_hookshot_metrics_enabled: true`). These metrics will be collected from the local (in-container) Prometheus over the container network.
+  - If Prometheus is enabled (`prometheus_enabled: true`), then Hookshot metrics will be enabled automatically (`matrix_hookshot_metrics_enabled: true`). These metrics will be collected from the local (in-container) Prometheus over the container network.
   - **If Prometheus is not enabled** (you are either not using Prometheus or are using an external one), **Hookshot metrics will not be enabled by default anymore**. Feel free to enable them by setting `matrix_hookshot_metrics_enabled: true`. Also, see below.
 2. When metrics are meant to be **consumed by an external Prometheus server**, `matrix_hookshot_metrics_proxying_enabled` needs to be set to `true`, so that metrics would be exposed (proxied) "publicly" on `https://matrix.DOMAIN/metrics/hookshot`. To make use of this, you'll also need to enable the new `https://matrix.DOMAIN/metrics/*` endpoints mentioned above, using `matrix_nginx_proxy_proxy_matrix_metrics_enabled`. Learn more in our [Collecting metrics to an external Prometheus server](docs/configuring-playbook-prometheus-grafana.md#collecting-metrics-to-an-external-prometheus-server) documentation.
 3. **We've changed the URL we're exposing Hookshot metrics at** for external Prometheus servers. Until now, you were advised to consume Hookshot metrics from `https://stats.DOMAIN/hookshot/metrics` (working in conjunction with `matrix_nginx_proxy_proxy_synapse_metrics`). From now on, **this no longer works**. As described above, you need to start consuming metrics from `https://matrix.DOMAIN/metrics/hookshot`.