Merge branch '212882-add-cpu-mem-charts' into 'master'

Add charts showing CPU and memory usage to self monitoring default dashboard

See merge request gitlab-org/gitlab!33532

changelogs/unreleased/212882-add-cpu-mem-charts.yml

+---
+title: Add CPU, memory usage charts to self monitoring default dashboard
+merge_request: 33532
+author:
+type: changed

config/prometheus/self_monitoring_default.yml

 dashboard: 'Default dashboard'
 priority: 1
 panel_groups:
+
+- group: 'Resource usage'
+  panels:
+  - title: "Memory usage"
+    type: "line-chart"
+    y_label: "% memory used"
+    metrics:
+    - id: node_memory_usage_percentage
+      query_range: '(1 - (node_memory_MemAvailable_bytes or node_memory_MemFree_bytes + node_memory_Buffers_bytes + node_memory_Cached_bytes + node_memory_Slab_bytes) / node_memory_MemTotal_bytes) * 100'
+      unit: "%"
+      label: instance
+
+  - title: "CPU usage"
+    type: "line-chart"
+    y_label: "% CPU used"
+    metrics:
+    - id: node_cpu_usage_percentage
+      query_range: '(avg without (mode,cpu) (1 - irate(node_cpu_seconds_total{mode="idle"}[5m]))) * 100'
+      unit: "%"
+      label: instance
+
 - group: Web Service
   panels:
     - title: Web Service - Error Ratio

doc/administration/monitoring/gitlab_self_monitoring_project/index.md

@@ -21,10 +21,12 @@ All administrators at the time of creation of the project and group will be adde
 as maintainers of the group and project, and as an admin, you'll be able to add new
 members to the group in order to give them maintainer access to the project.
 
-This project is used to self monitor your GitLab instance. Metrics are not yet
-fully integrated, and the dashboard does not aggregate any data on Omnibus installations. GitLab plans
-to provide integrated self-monitoring metrics in a future release. You can
-currently use the project to configure your own [custom metrics](../../../user/project/integrations/prometheus.md#adding-custom-metrics) using
+This project is used to self monitor your GitLab instance. The metrics dashboard
+of the project shows some basic resource usage charts, such as CPU and memory usage
+of each server in [Omnibus GitLab](https://docs.gitlab.com/omnibus/) installations.
+
+You can also use the project to configure your own
+[custom metrics](../../../user/project/integrations/prometheus.md#adding-custom-metrics) using
 metrics exposed by the [GitLab exporter](../prometheus/gitlab_metrics.md#metrics-available).
 
 ## Creating the self monitoring project