The Discourse Prometheus plugin is the official Prometheus exporter for Discourse, allowing users to collect and expose metrics via the /metrics endpoint. It tracks various data points such as page load times, error rates, Ruby object space, V8 memory, and Sidekiq job durations. Metrics are aggregated across all unicorn processes and can be visualized in Grafana using a provided dashboard. The plugin supports configuring trusted IPs via the prometheus_trusted_ip_allowlist_regex setting, which can be set in app.yml. Users have raised questions about its behavior in Kubernetes environments, where it aggregates metrics from multiple pods, and its performance, with some reporting issues like 404 errors in Grafana. One user resolved their issue by referencing a related Meta discussion.
Scheduled Job Queue and Sidekiq job durations and executions.
To see a full list of metrics available, install the plugin and visit SITENAME/metrics as an admin.
Out of the box we allow the metrics route to admins and private ips.
Discourse Prometheus is smart enough to aggregate data for all forked unicorn processes and present it as cohesive metrics on a single endpoint. We use it internally to keep track of our sites.
Sample dashboard at:
Discourse global setting called prometheus_trusted_ip_allowlist_regex (env: DISCOURSE_PROMETHEUS_TRUSTED_IP_ALLOWLIST_REGEX) is allowing to set Prometheus’s trusted IP addresses. The setting accepts regular expression to set advanced IP ranges. This is useful in a case when Prometheus IP address is dynamic.
I’m currently managing discourse on Kubernetes, running on multiple app and sidekiq pods. I have a couple of questions regarding the plugin:
Does the plugin aggregate metrics from all the app pods? I’m assuming it does aggregate metrics for unicorn processes running on a single instance/pod.
Not sure what’s happening but this integration is not working anymore. I couldn’t get the dashboard in grafana to display anything… the /metrics does return something but anything beyond that does not really work
Many errors like the one below
Started GET "/metrics/api/v1/label/instance/values?limit=40000&start=1760980620&end=1760982480&match%5B%5D=discourse_page_views" for 16.63.57.20 at 2025-10-20 17:47:07 +0000
Started GET "/metrics/api/v1/label/job/values?limit=40000&start=1760980620&end=1760982480&match%5B%5D=discourse_page_views%7B%7D" for 16.63.57.20 at 2025-10-20 17:47:07 +0000
Rendered layout layouts/no_ember.html.erb (Duration: 21.1ms | GC: 0.0ms)
Rendered layout layouts/no_ember.html.erb (Duration: 26.0ms | GC: 0.0ms)
Started POST "/metrics/api/v1/query_range" for 16.63.57.20 at 2025-10-20 17:47:07 +0000
Started POST "/metrics/api/v1/query_range" for 16.63.57.20 at 2025-10-20 17:47:07 +0000
Started POST "/metrics/api/v1/query_range" for 16.63.57.20 at 2025-10-20 17:47:07 +0000
Started POST "/metrics/api/v1/query_range" for 16.63.57.20 at 2025-10-20 17:47:07 +0000
Started POST "/metrics/api/v1/query_range" for 16.63.57.20 at 2025-10-20 17:47:07 +0000
Rendered layout layouts/no_ember.html.erb (Duration: 19.8ms | GC: 0.0ms)
Rendered layout layouts/no_ember.html.erb (Duration: 28.2ms | GC: 0.0ms)
Rendered layout layouts/no_ember.html.erb (Duration: 34.6ms | GC: 0.0ms)
Rendered layout layouts/no_ember.html.erb (Duration: 44.4ms | GC: 0.0ms)
Rendered layout layouts/no_ember.html.erb (Duration: 41.7ms | GC: 0.0ms)
Started POST "/metrics/api/v1/query_range" for 16.63.57.20 at 2025-10-20 17:47:07 +0000
Started POST "/metrics/api/v1/query_range" for 16.63.57.20 at 2025-10-20 17:47:08 +0000
Started POST "/metrics/api/v1/query_range" for 16.63.57.20 at 2025-10-20 17:47:08 +0000
Started POST "/metrics/api/v1/query_range" for 16.63.57.20 at 2025-10-20 17:47:08 +0000
Rendered layout layouts/no_ember.html.erb (Duration: 23.6ms | GC: 0.0ms)
Rendered layout layouts/no_ember.html.erb (Duration: 24.9ms | GC: 0.0ms)
Rendered layout layouts/no_ember.html.erb (Duration: 19.9ms | GC: 0.0ms)
Rendered layout layouts/no_ember.html.erb (Duration: 21.6ms | GC: 0.0ms)
Started GET "/metrics/api/v1/label/job/values?limit=40000&start=1760980620&end=1760982480&match%5B%5D=discourse_page_views%7B%7D" for 16.63.57.20 at 2025-10-20 17:47:37 +0000
Started GET "/metrics/api/v1/label/instance/values?limit=40000&start=1760980620&end=1760982480&match%5B%5D=discourse_page_views" for 16.63.57.20 at 2025-10-20 17:47:37 +0000
Rendered layout layouts/no_ember.html.erb (Duration: 19.5ms | GC: 0.0ms)
Rendered layout layouts/no_ember.html.erb (Duration: 20.9ms | GC: 0.0ms)
Started POST "/metrics/api/v1/query_range" for 16.63.57.20 at 2025-10-20 17:47:37 +0000
Started POST "/metrics/api/v1/query_range" for 16.63.57.20 at 2025-10-20 17:47:37 +0000
Started POST "/metrics/api/v1/query_range" for 16.63.57.20 at 2025-10-20 17:47:37 +0000
Started POST "/metrics/api/v1/query_range" for 16.63.57.20 at 2025-10-20 17:47:37 +0000
Started POST "/metrics/api/v1/query_range" for 16.63.57.20 at 2025-10-20 17:47:37 +0000
Rendered layout layouts/no_ember.html.erb (Duration: 22.4ms | GC: 0.0ms)
Rendered layout layouts/no_ember.html.erb (Duration: 22.0ms | GC: 0.0ms)
Rendered layout layouts/no_ember.html.erb (Duration: 40.0ms | GC: 0.0ms)
Rendered layout layouts/no_ember.html.erb (Duration: 37.0ms | GC: 0.0ms)
Rendered layout layouts/no_ember.html.erb (Duration: 24.8ms | GC: 1.6ms)
