Merge remote-tracking branch 'upstream/master' into use-update-runner-service

* upstream/master: (488 commits)
  Remove duplicate CHANGELOG.md entries for 8.16.5
  Update CHANGELOG.md for 8.14.9
  Update CHANGELOG.md for 8.15.6
  #27631: Add missing top-area div to activity header page
  Update CHANGELOG.md for 8.16.5
  Update CHANGELOG.md for 8.16.5
  Update CHANGELOG.md for 8.16.5
  Fix yarn lock and package.json mismatch caused by MR 9133
  sync yarn.lock with recent changes to package.json
  Add changelog
  Fix z index bugs
  Add Links to Branches in Calendar Activity
  SidekiqStatus need to be qualified in some cases
  Replace static fixture for behaviors/requires_input_spec.js (!9162)
  API: Consolidate /projects endpoint
  Add MySQL info in install requirements
  Fix timezone on issue boards due date
  Use Gitlab::Database.with_connection_pool from !9192
  Disconnect the pool after done
  Use threads directly, introduce pool later:
  ...

1 files changed, 33 insertions, 0 deletions

diff --git a/doc/administration/monitoring/prometheus/redis_exporter.md b/doc/administration/monitoring/prometheus/redis_exporter.md
new file mode 100644
index 00000000000..d54d409dbb6
--- /dev/null
+++ b/doc/administration/monitoring/prometheus/redis_exporter.md
@@ -0,0 +1,33 @@
+# Redis exporter
+
+>**Note:**
+Available since [Omnibus GitLab 8.17][1118]. For installations from source
+you'll have to install and configure it yourself.
+
+The [Redis exporter] allows you to measure various [Redis] metrics. For more
+information on what's exported [read the upstream documentation][redis-exp].
+
+To enable the Redis exporter:
+
+1. [Enable Prometheus](index.md#configuring-prometheus)
+1. Edit `/etc/gitlab/gitlab.rb`
+1. Add or find and uncomment the following line, making sure it's set to `true`:
+
+    ```ruby
+    redis_exporter['enable'] = true
+    ```
+
+1. Save the file and [reconfigure GitLab][reconfigure] for the changes to
+   take effect
+
+Prometheus will now automatically begin collecting performance data from
+the Redis exporter exposed under `localhost:9121`.
+
+[← Back to the main Prometheus page](index.md)
+
+[1118]: https://gitlab.com/gitlab-org/omnibus-gitlab/merge_requests/1118
+[redis]: https://redis.io
+[redis exporter]: https://github.com/oliver006/redis_exporter
+[redis-exp]: https://github.com/oliver006/redis_exporter/blob/master/README.md#whats-exported
+[prometheus]: https://prometheus.io
+[reconfigure]: ../../restart_gitlab.md#omnibus-gitlab-reconfigure