Allow disabling usage ping in `gitlab.yml`

Setting `usage_ping_enabled` to false in `gitlab.yml`:

1. Disables the usage ping, regardless of the value stored in the database.
2. Prevents the usage ping from being enabled through the admin panel. It can
   only be enabled by either removing the line from `gitlab.yml` and configuring
   through the admin panel, or setting it to true in `gitlab.yml`.

1 files changed, 18 insertions, 0 deletions

diff --git a/doc/user/admin_area/settings/usage_statistics.md b/doc/user/admin_area/settings/usage_statistics.md
index 733e70ca9bf..6198d4864fa 100644
--- a/doc/user/admin_area/settings/usage_statistics.md
+++ b/doc/user/admin_area/settings/usage_statistics.md
@@ -89,6 +89,24 @@ By default, usage ping is opt-out. If you want to deactivate this feature, go to
 the Settings page of your administration panel and uncheck the Usage ping
 checkbox.
 
+To disable the usage ping and prevent it from being configured from the
+administration panel, Omnibus installs can set the following in
+[`gitlab.rb`](https://docs.gitlab.com/omnibus/settings/configuration.html#configuration-options):
+
+```ruby
+gitlab_rails['usage_ping_enabled'] = false
+```
+
+And source installs can set the following in `gitlab.yml`:
+
+```yaml
+production: &base
+  # ...
+  gitlab:
+    # ...
+    usage_ping_enabled: false
+```
+
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