matrix-docker-ansible-deploy/docs/configuring-playbook-prometheus-grafana.md

Enabling metrics and graphs for your Matrix server (optional)

It can be useful to have some (visual) insight into the performance of your homeserver.

You can enable this with the following settings in your configuration file (inventory/host_vars/matrix.<your-domain>/vars.yml):

Remember to add stats.<your-domain> to DNS as described in Configuring DNS before running the playbook.

prometheus_enabled: true

# You can remove this, if unnecessary.
prometheus_node_exporter_enabled: true

# You can remove this, if unnecessary.
prometheus_postgres_exporter_enabled: true

# You can remove this, if unnecessary.
matrix_prometheus_nginxlog_exporter_enabled: true

grafana_enabled: true

grafana_anonymous_access: false

# This has no relation to your Matrix user id. It can be any username you'd like.
# Changing the username subsequently won't work.
grafana_default_admin_user: "some_username_chosen_by_you"

# Changing the password subsequently won't work.
grafana_default_admin_password: "some_strong_password_chosen_by_you"

By default, a Grafana web user-interface will be available at https://stats.<your-domain>.

The retention policy of Prometheus metrics is 15 days by default. Older data gets deleted automatically.

What does it do?

Name	Description
prometheus_enabled	Prometheus is a time series database. It holds all the data we're going to talk about.
prometheus_node_exporter_enabled	Node Exporter is an addon of sorts to Prometheus that collects generic system information such as CPU, memory, filesystem, and even system temperatures
prometheus_postgres_exporter_enabled	Postgres Exporter is an addon of sorts to expose Postgres database metrics to Prometheus.
matrix_prometheus_nginxlog_exporter_enabled	NGINX Log Exporter is an addon of sorts to expose NGINX logs to Prometheus.
grafana_enabled	Grafana is the visual component. It shows (on the stats.<your-domain> subdomain) the dashboards with the graphs that we're interested in
grafana_anonymous_access	By default you need to log in to see graphs. If you want to publicly share your graphs (e.g. when asking for help in #synapse:matrix.org) you'll want to enable this option.
grafana_default_admin_user grafana_default_admin_password	By default Grafana creates a user with admin as the username and password. If you feel this is insecure and you want to change it beforehand, you can do that here

Security and privacy

Metrics and resulting graphs can contain a lot of information. This includes system specs but also usage patterns. This applies especially to small personal/family scale homeservers. Someone might be able to figure out when you wake up and go to sleep by looking at the graphs over time. Think about this before enabling anonymous access. And you should really not forget to change your Grafana password.

Most of our docker containers run with limited system access, but the prometheus-node-exporter has access to the host network stack and (readonly) root filesystem. This is required to report on them. If you don't like that, you can set prometheus_node_exporter_enabled: false (which is actually the default). You will still get Synapse metrics with this container disabled. Both of the dashboards will always be enabled, so you can still look at historical data after disabling either source.

Collecting metrics to an external Prometheus server

If the integrated Prometheus server is enabled (prometheus_enabled: true), metrics are collected by it from each service via communication that happens over the container network. Each service does not need to expose its metrics "publicly".

When you'd like to collect metrics from an external Prometheus server, you need to expose service metrics outside of the container network.

The playbook provides a single endpoint (https://matrix.DOMAIN/metrics/*), under which various services may expose their metrics (e.g. /metrics/node-exporter, /metrics/postgres-exporter, /metrics/hookshot, etc). To enable this /metrics/* feature, use matrix_nginx_proxy_proxy_matrix_metrics_enabled. To protect access using Basic Authentication, see matrix_nginx_proxy_proxy_matrix_metrics_basic_auth_enabled below.

The following variables may be of interest:

Name	Description
matrix_nginx_proxy_proxy_matrix_metrics_enabled	Set this to true to enable metrics exposure for various services on https://matrix.DOMAIN/metrics/*. Refer to the individual matrix_SERVICE_metrics_proxying_enabled variables below for exposing metrics for each individual service.
matrix_nginx_proxy_proxy_matrix_metrics_basic_auth_enabled	Set this to true to protect all https://matrix.DOMAIN/metrics/* endpoints with Basic Authentication (see the other variables below for supplying the actual credentials). When enabled, all endpoints beneath /metrics will be protected with the same credentials
matrix_nginx_proxy_proxy_matrix_metrics_basic_auth_username	Set this to the Basic Authentication username you'd like to protect /metrics/* with. You also need to set matrix_nginx_proxy_proxy_matrix_metrics_basic_auth_password. If one username/password pair is not enough, you can leave the username and password variables unset and use matrix_nginx_proxy_proxy_matrix_metrics_basic_auth_raw_content instead
matrix_nginx_proxy_proxy_matrix_metrics_basic_auth_password	Set this to the Basic Authentication password you'd like to protect /metrics/* with
matrix_nginx_proxy_proxy_matrix_metrics_basic_auth_raw_content	Set this to the Basic Authentication credentials (raw htpasswd file content) used to protect /metrics/*. This htpasswd-file needs to be generated with the htpasswd tool and can include multiple username/password pairs. If you only need one credential, use matrix_nginx_proxy_proxy_matrix_metrics_basic_auth_username and matrix_nginx_proxy_proxy_matrix_metrics_basic_auth_password instead.
matrix_synapse_metrics_enabled	Set this to true to make Synapse expose metrics (locally, on the container network)
matrix_synapse_metrics_proxying_enabled	Set this to true to expose Synapse's metrics on https://matrix.DOMAIN/metrics/synapse/main-process and https://matrix.DOMAIN/metrics/synapse/worker/TYPE-ID (only takes effect if matrix_nginx_proxy_proxy_matrix_metrics_enabled: true). Read below if you're running a Synapse worker setup (matrix_synapse_workers_enabled: true).
prometheus_node_exporter_enabled	Set this to true to enable the node (general system stats) exporter (locally, on the container network)
matrix_prometheus_services_proxy_connect_prometheus_node_exporter_metrics_proxying_enabled	Set this to true to expose the node (general system stats) metrics on https://matrix.DOMAIN/metrics/node-exporter (only takes effect if matrix_nginx_proxy_proxy_matrix_metrics_enabled: true)
prometheus_postgres_exporter_enabled	Set this to true to enable the Postgres exporter (locally, on the container network)
matrix_prometheus_nginxlog_exporter_enabled	Set this to true to enable the NGINX Log exporter (locally, on the container network)
matrix_prometheus_services_proxy_connect_prometheus_postgres_exporter_metrics_proxying_enabled	Set this to true to expose the Postgres exporter metrics on https://matrix.DOMAIN/metrics/postgres-exporter (only takes effect if matrix_nginx_proxy_proxy_matrix_metrics_enabled: true)
matrix_bridge_hookshot_metrics_enabled	Set this to true to make Hookshot expose metrics (locally, on the container network)
matrix_bridge_hookshot_metrics_proxying_enabled	Set this to true to expose the Hookshot metrics on https://matrix.DOMAIN/metrics/hookshot (only takes effect if matrix_nginx_proxy_proxy_matrix_metrics_enabled: true)
matrix_SERVICE_metrics_proxying_enabled	Various other services/roles may provide similar _metrics_enabled and _metrics_proxying_enabled variables for exposing their metrics. Refer to each role for details. Only takes effect if matrix_nginx_proxy_proxy_matrix_metrics_enabled: true
matrix_nginx_proxy_proxy_matrix_metrics_additional_user_location_configuration_blocks	Add nginx location blocks to this list if you'd like to expose additional exporters manually (see below)

Example for how to make use of matrix_nginx_proxy_proxy_matrix_metrics_additional_user_location_configuration_blocks for exposing additional metrics locations:

matrix_nginx_proxy_proxy_matrix_metrics_additional_user_location_configuration_blocks:
  - 'location /metrics/another-service {
  resolver 127.0.0.11 valid=5s;
  proxy_pass http://matrix-another-service:9100/metrics;
  }'

Using matrix_nginx_proxy_proxy_matrix_metrics_additional_user_location_configuration_blocks only takes effect if matrix_nginx_proxy_proxy_matrix_metrics_enabled: true (see above).

Note : The playbook will hash the basic_auth password for you on setup. Thus, you need to give the plain-text version of the password as a variable.

Collecting Synapse worker metrics to an external Prometheus server

If you are using workers (matrix_synapse_workers_enabled: true) and have enabled matrix_synapse_metrics_proxying_enabled as described above, the playbook will also automatically expose all Synapse worker threads' metrics to https://matrix.DOMAIN/metrics/synapse/worker/ID, where ID corresponds to the worker id as exemplified in matrix_synapse_workers_enabled_list.

The playbook also generates an exemplary config file (/matrix/synapse/external_prometheus.yml.template) with all the correct paths which you can copy to your Prometheus server and adapt to your needs. Make sure to edit the specified password_file path and contents and path to your synapse-v2.rules. It will look a bit like this:

scrape_configs:
  - job_name: 'synapse'
    metrics_path: /metrics/synapse/main-process
    scheme: https
    basic_auth:
      username: prometheus
      password_file: /etc/prometheus/password.pwd
    static_configs:
      - targets: ['matrix.DOMAIN:443']
        labels:
          job: "master"
          index: 1
  - job_name: 'matrix-synapse-synapse-worker-generic-worker-0'
    metrics_path: /metrics/synapse/worker/generic-worker-0
    scheme: https
    basic_auth:
      username: prometheus
      password_file: /etc/prometheus/password.pwd
    static_configs:
      - targets: ['matrix.DOMAIN:443']
        labels:
          job: "generic_worker"
          index: 18111

More information

• Understanding Synapse Performance Issues Through Grafana Graphs at the Synapse Github Wiki
• The Prometheus scraping rules (we use v2)
• The Synapse Grafana dashboard
• The Node Exporter dashboard (for generic non-synapse performance graphs)